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Surface Chemistry:
03:00pm - 06:40pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 2
Steven Tait, Organizer; Andrew Teplyakov, Organizer; Lorena Tribe, Organizer; Esther Frederick, Presider; Oliva Primera, Presider
Division: [COLL] Division of Colloid & Surface Chemistry
Session Type: Oral - Virtual
Division/Committee: [COLL] Division of Colloid & Surface Chemistry

This symposium will consist of oral presentations on new advances in surface chemistry, including reactions at surfaces, chemisorption, adsorption/desorption, deposition and growth, kinetics of surface processes, surface structure, nanomaterials at surfaces, advances in surface analysis, manipulation of surface structure and chemistry, self-assembly at surfaces, and other topics related to surface chemistry. These sessions will include interdisciplinary topics relevant to fundamental surface chemistry, as well as to a range of chemical and materials applications.

Thursday
3643263 - Tracing the defect of the metal oxide surfaces by small probing molecule and IR spectra OnDemand
03:00pm - 03:20pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 2
Division: [COLL] Division of Colloid & Surface Chemistry
Session Type: Oral - Virtual
The surface defects play fundamental role in the physical and chemical properties of metal oxide surface. Based on the p-polarized infrared reflection absorption spectroscopy (IRRAS) and small probing molecules, we have traced the distribution of defect-induced polarons on the reduced TiO2(110) surface, a long-standing controversy for transition metal oxides (Figure 1a). By dosing the NO molecules, two IR absorption bands have been observed at 1751 and 1626 cm-1 (Figure 1b), respectively, which have never been reported on rutile-TiO2(110) surfaces before. DFT calculations indicate that the NO molecules are adsorbed at the bridge oxygen vacancy (Vo) and Ti5c sites, respectively. It is noteworthy that both sites possess excess electrons, i.e. the polarons, from the reduced TiO2. The adsorption of CO also supports the presence of polaron states, which is in good agreement with the microscopy results. In the case of single crystal CoO(001) surface, an superstructure with large periodic lattices (3√2×3√2) has been detected by low energy electron diffraction (Figure 1c). The relation between the superstructure and the Vo has been verified by the vibrational frequency fingerprint of CO probing molecules characterized by the IRRAS. A weak band at 2191 cm-1 first occurs from the low CO exposure of 0.01 L (Figure 1d). On the other hand, if the CoO(001) surface is first exposed to O2 and then to CO, the 2191 cm-1 band no longer appears (Figure 1e). Such results demonstrate that the superstructure is related to the Vo of the CoO surface. Our results suggest that the probing molecule in conjunction with the IR spectra is a promising approach to study the defects of crystal surfaces.

Thursday
3651209 - Area-selective atomic layer deposition templated by atomic precision fabrication
03:20pm - 03:40pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 2
Division: [COLL] Division of Colloid & Surface Chemistry
Session Type: Oral - Virtual
Atomic precision advanced manufacturing (APAM) leverages the chemical contrast created by selectively desorbing a hydrogen or halogen resist to expose highly reactive dangling bond patterns on silicon. The high reactivity of these dangling bonds allows selective deposition of molecular precursors into de-passivated regions at scales ranging from atoms to microns, but the high reactivity of these dangling bonds also limited the use of APAM-patterned surfaces to ultra-high vacuum (UHV) environments. Recently, bromine and iodine were shown to passivate the dangling bonds on APAM-patterned H-Si to provide ambient stability on the order of hours. While historically used to fabricate donor-based quantum devices, the chemical contrast produced by the APAM process can now also be leveraged in area-selective atomic layer deposition (AS-ALD) processes. The recently demonstrated H/halogen co-patterned surface can be removed from UHV and integrated with ALD processing tools for selective film growth templated by the APAM pattern. This is similar to techniques used in AS-ALD and bias mode atomic force microscope (AFM) nanolithography which leverages differences in surface chemistry, such as oxide versus hydrogen, to template growth. In this work, we demonstrate AS-ALD templated on Si utilizing APAM co-patterning methods. This points to a generalizable path for templating growth of materials by combining state-of-the-art atomic-precision fabrication capabilities with traditional ALD processes.
Thursday
Polyoxometalates (POMs) containing localized spins have potential as molecular qubits for quantum computing applications. POMs may accommodate magnetic atoms such as V in their structures, resulting in novel molecules with promising magneto/electro-optical properties. However, for practical applications, molecular qubits need to be prepared in optically-addressable arrays which imposes unavoidable interactions with underlying supports and adjacent POMs. In particular, spin-lattice (phonon) coupling is an influential decoherence mechanism that remains insufficiently understood for supported molecular qubits.
Herein, we synthesized POMs containing different numbers of V atoms and transferred them into the gas phase using electrospray ionization. Ion soft landing, a versatile surface modification technique, was used to deliver mass-selected POMs with predetermined V-composition to different self-assembled monolayer surfaces (SAMs) with controlled coverage. Conventional alkylthiol (HSAM), hydrophobic perfluorinated alkylthiol (FSAM), and hydrophilic carboxylic-acid (COOH-SAM) surfaces on gold were selected as well-defined model supports with which to characterize POM-substrate and POM-POM interactions. Infrared reflection absorption spectroscopy (IRRAS), scattering-type scanning near-field optical microscopy (s-SNOM), and density functional (DFT) theoretical calculations provide insight into the vibrational modes of supported POMs, how they are influenced by V-doping, and how they are perturbed by interaction with the HSAM, FSAM, and COOH-SAM surfaces. Spatially-resolved s-SNOM results also reveal the VPOM distribution on the SAM supports and the effect of surface coverage on the POM-SAM and POM-POM interactions. The electronic properties of the bare POMs are determined by negative ion photoelectron spectroscopy (NIPES) and cyclic voltammetry (CV), while the supported POMs are investigated by electrostatic force microscopy (EFM) and scanning Kelvin probe microscopy (KPFM). Our results provide fundamental insight into how POM-support and POM-POM interactions influence the vibrations of supported molecular qubits, which is central to increasing their coherence times for eventual applications.

Thursday
3658389 - Why are polymorphs of acenequinones on Ag(111) so different?
04:00pm - 04:20pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 2
Division: [COLL] Division of Colloid & Surface Chemistry
Session Type: Oral - Virtual
The drive towards miniaturization and nanotechnology requires understanding and controlling surface polymorphism at a molecular level. Which polymorph forms depends on intricate interaction mechanisms.

In this collaboration between theory and experiment, we present a thorough study of the mechanisms behind the surprisingly diverse experimental surface polymorphs of the homologous series of acenequinones on Ag(111).[1] Using the SAMPLE approach[2], which combines coarse graining, density functional theory and machine learning, allows predicting the energetically most favorable polymorphs.

Analyzing these polymorphs reveals three important driving forces: i) molecule- substrate interactions favor specific adsorption geometries; ii) molecule-molecule interactions favor the formation of densely packed structures; and iii) steric hindrance in part inhibits otherwise beneficial molecular arrangements.

Thursday
N-Heterocyclic Carbenes (NHCs) are prone to form strong chemical bonds to surfaces, thanks to their pronounced electron-donor character, which enables their use in surface functionalization for various applications, from gas sensing to optoelectronics and (photo)catalysis. At the state of the art, the adsorption of carbene molecules has mostly been studied on gold, with few works being dedicated to other substrates such as copper. In the present work, we go beyond by depositing and characterizing NHCs on three different substrates: Cu(100), clean Cu(111) and Cu(111) covered by a thin CuxO oxide layer. The characterization is performed by means of Scanning Tunnelling Microscopy (STM) and Density Functional Theory Calculations (DFT).
An intriguing feature is observed upon adsorption of a model NHC, 1,3-bis(2,6- diisopropylphenyl)imidazol-2-ylidene (IPr-NHC) on Cu(100) and Cu(111): on Cu(100) the molecules do not display well-ordered structures until the coverage is high enough to form small closed-packed patches. On Cu(111) well defined structures appear already at low coverages. This fact is related to the different diffusion barriers found for IPr-NHC on the two substrates. Two diffusion mechanisms are possible, one requiring the extraction of a surface Cu atom, forming a ballbot species, and another one based on adsorption/readsorption diffusion. For both mechanisms, the calculated diffusion barrier is lower on Cu(111) than on Cu(100). Although the long-range arrangements on both substrates are different, the molecule-molecule distance for the ordered structures is the same: 1.2 nm. This is related to the fact that IPr-NHC adsorbs in upright configuration on both Cu(100) and Cu(111), leading to equivalent intermolecular interactions.
On CuxO/Cu(111), the molecules bind strongly to oxygen atoms from the oxide layer, which governs the formation of the molecular layer. In this respect, a series of simulations has been performed highlighting the role of the NHC’s side substituents, spanning from isopropylphenyl, to phenyl, methyl and hydrogen. The steric hindrance induced by the side substituents influences both the chemical bond of the carbene centre to the surface and the non-specific dispersive interactions to the substrate.

Thursday
Intermission
04:40pm - 04:40pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 2
Division: [COLL] Division of Colloid & Surface Chemistry
Session Type: Oral - Virtual

Thursday
3661680 - Carbon particulate adsorption to aqueous – air interfaces and their effects on model biological membrane structure and organization
04:40pm - 05:00pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 2
Division: [COLL] Division of Colloid & Surface Chemistry
Session Type: Oral - Virtual
Although freshly emitted black carbon aerosols are constituted largely of hydrophobic carbon particulates (CPs), oxidation and prolonged exposure to other aerosol constituents renders BC particulates more hydrophilic and soluble in aqueous solution. BC aerosols change the structural, elastic, and dynamic properties of biological membranes, but the mechanism(s) responsible for these effects remain poorly characterized. To quantify surface activity of soluble and insoluble CPs and their effects on lipid monolayers, a suite of surface specific linear and nonlinear optical methods and thermodynamic analyses were used to measure how CPs alter lipid monolayer organization, orientation, and compressibility at aqueous – air interfaces. Insoluble CPs remain physisorbed to aqueous surfaces, but surface tension data show that soluble CPs are also surface active with a limiting surface excess of 155 Å2/molecule. CP surface activity also manifests in 2nd order nonlinear optical measurements. Data from surface specific vibrational sum frequency generation experiments show that interactions between soluble CPs and lipid monolayers at the aqueous – air interface condense lipid monolayers, with high variability observed at lower CP concentrations. Soluble CPs increase lipid acyl chain ordering in 55Å2/molecule DPPC films at both very low CP concentrations and CP concentrations above 5 mg/ml. Such behavior is consistent with soluble CP aggregates occupying area at the aqueous – air interface, effectively compressing DPPC domains. Spectroscopic ellipsometry (SE) measurements reveal that these behaviors also affect the optical properties of a biological film with the most pronounced effects observed with low soluble CP concentrations.
Thursday
3655763 - Efficient inactivation of SARS-CoV-2 and killing of bacteria using transparent silver oxide coating
05:00pm - 05:20pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 2
Division: [COLL] Division of Colloid & Surface Chemistry
Session Type: Oral - Virtual
The COVID-19 pandemic caused a huge surge in morbidity and mortality. Although the primary transmission mode of this disease is through the inhalation of droplets contaminated with the SARS-CoV-2 virus, transmission through the contaminated objects (fomites) also occurs and is accountable for 25% of diseased cases. Fomite transmission is also responsible for the spread of a number of pathogenic bacteria such as Pseudomonas aeruginosa (P. aeruginosa), Staphylococcus aureus (S. aureus) and MRSA. Antimicrobial coatings and surfaces can limit the fomite transmission route by inactivating the virus or killing the bacteria in a shorter time than on an uncoated surface, thereby reducing the time period in which an object remains contaminated. In this work, we designed and fabricated a silver oxide surface coating capable of significantly reducing the load of viable microbes on surfaces. First, we synthesized Ag2O microparticles and then we bound them to glass substrate using a variant of Stöber sol-gel process. We tested the coated surfaces with two different Ag2O loadings by placing contaminated suspension droplets on the surface. The infectivity of SARS-CoV-2 virus was tested on African Green Monkey Cells (Vero E6) and the survival of P. aeruginosa, S. aureus and MRSA were each tested by colony forming unit. Comparing the coated to uncoated surfaces, the titer of SARS-CoV-2 was reduced by 99.8% and the number of bacteria was reduced by >99.9% on average after one hour on Ag2O coated surfaces. The second important property of the coating is that we have shown that it is transparent, and that the transmission of light is approximately uniform across the visible spectrum, meaning that it does not distort color. The combination of strong antimicrobial activity and transparency means that this coating can be applied to cell phone touch screens and checkout facilities to limit the transmission of microbes.
Thursday
3655183 - Insights into adsorption of humic substances on various graphitic carbon nitride
05:20pm - 05:40pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 2
Division: [COLL] Division of Colloid & Surface Chemistry
Session Type: Oral - Virtual
More recently, graphitic carbon nitride (CN) has been widely applied in the photodegradation of organic pollutants. However, there are no studies focusing on its adsorption, which has been recognized as the critical steps of photocatalysis. Moreover, ubiquitous humic substances (HSs) in natural water and wastewaters can inevitably interact with CNs, disturbing the photocatalysis of target pollutants. Herein, HSs [i.e. humic acid (HA) and fulvic acid (FA)] adsorption on CNs derived from four typical precursors was investigated. Interestingly, CN derived from urea exhibited the great adsorption capacity for HSs, attributed to porosity and high surface area; the maximum adsorption determined by the Langmuir model reached 73.24 and 51.62 mgC/g for HA and FA, respectively, showing great promises for HSs elimination. HSs adsorption on CNs was mainly regulated by electrostatic interactions, π-conjugation, hydrogen bonding, and surface complexation (see Figure 1). Particularly, given the heterogeneity of HSs, the strongly competitive adsorption was observed between HSs components; HSs components with high aromaticity showed great adsorption affinity. In addition, HSs adsorption on CNs under the solution chemistry widely used for CNs-photocatalysis was also proven. These results revealed that HSs macromolecules definitely competed for active sites, interfering the adsorption of other pollutants for further photodegradation. These findings provide valuable insights into HSs adsorption and pose great challenges to the practical applications of CNs photocatalysts.
<b>Figure 1 </b>Schematic of multiple adsorption mechanisms between CNs and HSs

Figure 1 Schematic of multiple adsorption mechanisms between CNs and HSs


Thursday
3658782 - Substrate-induced charge transfer influencing multilayer growth: Insights from DFT and machine learning
05:40pm - 06:00pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 2
Division: [COLL] Division of Colloid & Surface Chemistry
Session Type: Oral - Virtual
Organic thin films exhibit a large structural variability, and many of their properties depend strongly on molecular arrangement. Which polymorph a thin film forms depends on a variety of factors, including the fabrication conditions and the properties of the substrate on which the film grows. Predicting which structure a thin film will assume on a substrate is impossible through traditional first-principle modeling alone, because of the combinatorial explosion in the number of possible polymorphs. Employing smart-data machine learning, we can now perform extensive layer-by-layer structure searches at organic/inorganic interfaces on the basis of only a few hundred first-principles calculations. Here, we use this method to study the first two layers of benzoquinone on two different substrates, Ag(111) and graphene, identifying the energetically most favorable structures on both substrates and studying their electronic properties. Our results indicate that for the first layer, similar structures are favorable on both substrates, while for the second layer we find different structures. Interestingly, graphene favors one, while Ag favors the other. We explain this switch in stability as an effect of the interplay between the different interlayer electronic coupling of the two structures and the different charge transfer on the two substrates.
Thursday
3641794 - Dual-loop active learning method to study the hydrophobicity of chemically heterogeneous surfaces OnDemand
06:00pm - 06:20pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 2
Division: [COLL] Division of Colloid & Surface Chemistry
Session Type: Oral - Virtual
The hydrophobicity of a material is a key property that drives numerous synthetic and biological processes in aqueous systems. While hydrophobicity can be quantified experimentally and predicted computationally for small molecules and larger, chemically uniform surfaces, predicting the hydrophobicity of chemically heterogeneous surfaces – surfaces with polar and nonpolar groups spatially arranged in different patterns on nanometer length scales – remains an outstanding challenge. While classical approaches consider additive effects of various chemical groups on the hydrophobicity based on their area coverage, these relations often fail to capture nonadditive contributions to the hydrophobicity of such surfaces that depend on the chemical identities and spatial patterns of polar and nonpolar groups. Computational methods like traditional molecular dynamics (MD) simulations and enhanced sampling techniques have made progress in understanding the effect of chemical heterogeneity on hydrophobicity. However, two major challenges in using computational approaches to explore the hydrophobicity of chemically heterogeneous surfaces are the large sampling times required for enhanced sampling techniques and the vast number of possible spatial patterns and combinations of polar/nonpolar groups possible in even small molecular systems.
In this work, we develop an active learning framework that utilizes MD simulations, enhanced sampling, and a convolutional neural network to predict the hydration free energy (a thermodynamic descriptor of hydrophobicity) for nearly 200,000 chemically heterogeneous self-assembled monolayers (SAMs). Analysis of this data set reveals that SAMs with distinct polar groups exhibit substantial variations in hydrophobicity as a function of their composition and patterning, but the clustering of nonpolar groups is a common signature of highly hydrophobic patterns. Further MD analysis relates such clustering to the perturbation of interfacial water structure. These results provide new insight into the influence of chemical heterogeneity on hydrophobicity via quantitative analysis of a large set of surfaces, enabled by the active learning approach.

Thursday
3659310 - Pressure driven flow of ionic liquid through asymmetrically charged contraction-expansion microfluidic device
06:20pm - 06:40pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 2
Division: [COLL] Division of Colloid & Surface Chemistry
Session Type: Oral - Virtual
The pressure-driven flow of ionic liquid through an asymmetrically charged rectangular microchannel has been investigated numerically using the finite element method. The mathematical model equations such as the Poisson and Navier-Stokes in conjunction with Nernst-Planck equations have been solved to obtain the electrical potential, charge, pressure, and induced electric fields for the following dimensionless conditions: inverse Debye length K = 2, top wall charge density ST = 8, charge density ratio (Sr = SB/ST) as 0 – 2 and Reynolds and Schmidt numbers (Re = 0.01, Sc = 1000). The current results have been compared with the literature for the limiting conditions and found to have good agreement with them. It is found that the asymmetry of the surface charge at the two walls of the microfluidic device plays a significant role in the development of flow fields. The higher asymmetry of surface charge increases the electroviscous effects in microfluidic device flow. The electroviscous correction factor (Y=ΔP/ΔP0) increases by 17% for Sr in the range of 0 to 2 at fixed K. The present results provide useful guidelines which may help in the design and engineering of the microfluidic devices.
Schematic representation of the flow and geometrical arrangements

Schematic representation of the flow and geometrical arrangements

Distribution of dimensionless (a) total electrical potential, (b) excess charge, and (c) pressure for S<sub>r</sub> = 0, 1, 2 at S<sub>T</sub> = 8 and K = 2

Distribution of dimensionless (a) total electrical potential, (b) excess charge, and (c) pressure for Sr = 0, 1, 2 at ST = 8 and K = 2


Emerging Science and Technologies of Bio-Based Nanomaterials: Self-Assembly of Bio-based Nanomaterials and Assembly of Nanomaterials and Polyelectrolytes
03:00pm - 06:40pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 5
Liangbing Hu, Organizer; Feng Jiang, Organizer, Presider; Silvia Vignolini, Organizer, Presider; Lars Wagberg, Organizer, Presider; Tian Li, Presider
Division: [CELL] Division of Cellulose and Renewable Materials
Session Type: Oral - Virtual
Division/Committee: [CELL] Division of Cellulose and Renewable Materials

With increasing understanding of the surface chemistry, structural design, and chemical/physical modification of bio-based nanomaterials (such as nano-cellulose, nano-chitin, nano-lignin, and nano-wood), emerging applications of these bio-based nanomaterials have been realized in many different fields. For example, bio-based nanomaterials have been found to possess unique physical, mechanical, optical, magnetic, piezoelectric, and charge properties that benefit energy harvesting and conversion. Such intrinsic properties can be further boosted by incorporating hierarchical structural design (such as self-assembly, sol-gel synthesis, ice-templating, and 3D printing) to introduce macro/meso/micro-porosities. Advanced applications of these bio-base nanomaterials in emerging fields of energy harvesting, energy storage, thermal regulating, sensors, and catalysts have attracted tremendous interests in global research communities. The aim of this symposium is to explore emerging science and technologies in structural design and advanced applications in emerging fields of bio-based nanomaterials.

Thursday
Introductory Remarks
03:00pm - 03:05pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 5
Division: [CELL] Division of Cellulose and Renewable Materials
Session Type: Oral - Virtual

Thursday
3649271 - Investigating the adsorption of charged nanolatexes onto cellulose model surfaces
03:05pm - 03:30pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 5
Division: [CELL] Division of Cellulose and Renewable Materials
Session Type: Oral - Virtual
Colloidal particles dispersed in water, so-called nanolatexes, have been used in both research and industry for decades. Hitherto, they are mainly produced via emulsion polymerization, where surface active agents, i.e. surfactants, are used for the stabilization of the hydrophobic core. However, the lack of covalent bonding between the surfactant and the hydrophobic polymer can lead to unfavorable effects such as the migration of the former. Nowadays, controlled radical polymerization techniques have also been employed for the synthesis of the aforementioned colloids. Specifically, reversible addition−fragmentation chain-transfer (RAFT)-mediated polymerization-induced self-assembly (PISA) in water has exhibited great versatility on the final chemistry and properties of the nanolatexes. Therefore, they can act as model systems, since the final properties can be tuned on-demand. Previously in our group, charged nanolatexes have been successfully used in the compatibilization of cellulose and cellulose nanofibrils (CNF) in coating and composite applications. However, there is a lack of an in-depth understanding of the key parameters that dominate their adsorption on these layers. In this work, charged nanolatexes synthesized through RAFT-mediated PISA with varying surface charge density and dimensions were adsorbed onto cellulose model surfaces (Fig. 1). Their adsorption was monitored by stagnation point absorption reflectometry (SPAR) and quartz crystal microbalance with dissipation (QCM-D).
Figure 1: Schematic representation (not to scale) of the adsorbed nanolatexes onto cellulose.

Figure 1: Schematic representation (not to scale) of the adsorbed nanolatexes onto cellulose.


Thursday
3657569 - Withdrawn
03:30pm - 03:55pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 5
Division: [CELL] Division of Cellulose and Renewable Materials
Session Type: Oral - Virtual

Thursday
3653973 - Withdrawn
03:55pm - 04:20pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 5
Session Type: Oral - Virtual

Thursday
3658153 - Surface-modified cellulose nanofibrils for composite and coating applications
04:20pm - 04:45pm USA / Canada - Pacific - March 24, 2022 | Location: Zoom Room 5
Division: [CELL] Division of Cellulose and Renewable Materials
Session Type: Oral - Virtual
In light of the urgency to design novel functional materials derived from renewable and sustainable resources, cellulose has attracted significant interest over the last decades as a high value biopolymer displaying potential as reinforcing element. Located in the plant cell wall, cellulose provides high mechanical strength combined with excellent performance in terms of flexibility. Cellulose-based materials with dimensions in the nanoscale have been developed, resulting in unique features linked to the isolation of highly ordered domains and a large surface area. Within the family of nanocelluloses, cellulose nanofibrils with high aspect ratio (CNFs) have proven to be promising bio-based reinforcing nanofillers for polymeric composites. However, given the hydrophilic nature of native cellulose, surface modification is essential to ensure compatibilization in hydrophobic matrices (such as the polymers commonly employed for industrial applications).
Aiming to address this challenge, various strategies for modifying the CNF surface in aqueous dispersion are explored in the present project. Atom Transfer Radical Polymerization (ATRP) is used as a tool for grafting hydrophobic polymer brushes from the CNF surface, as well as synthesizing copolymers with tailored structure and amphiphilic properties designed to electrostatically adsorb onto negatively charged CNFs and subsequently disperse them within a hydrophobic matrix. The interaction of the compatibilizing agents with the nanofibrils, as well as with the matrix, is investigated and optimized targeting specific composite and coating applications. The dispersion in the resin formulation is enhanced, allowing for the full exploitation of the nanomaterial’s reinforcing properties.

Thursday
3659146 - Nanocellulose as a glyconanomaterial platform towards bacterial capture and anti-adhesion
04:20pm - 04:45pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 5
Division: [CELL] Division of Cellulose and Renewable Materials
Session Type: Oral - Virtual
Cellulose nanofibrils (CNFs) derived from renewable resources are suitable for being a biocompatible polyvalent glyconanomaterial platform. The nanofibrils have low cytotoxicity toward human cells and tissues, and the prevalent hydroxyl or carboxylate groups on the CNFs enable the nanofibrils to be easily functionalized. In this study, carboxylated CNFs were rendered bioactive via one-step functionalization with mannopyranoside (CNFs-mannose) for control of bacterial pathogenesis. The recognition affinity of the bioactive surfaces towards fimbriated Escherichia coli (E. coli) was assessed using genetically engineered strain (FimH+) as well as wild-type (WT) MG1655 bacteria. The CNFs-mannose nanofibrils were capable of capturing E. coli from liquid suspensions, as demonstrated either by the nanofibril clusters or by the cellulose filter papers impregnated with CNFs-mannose. More importantly, CNFs-mannose efficiently inhibits adhesion of both FimH+ and WT E. coli to mannosylated surfaces even at a very low concentration, resulting in over 95% reduction of bacterial adhesion. The findings highlight the potential of cellulose nanofibrils as a biocompatible polyvalent nanoscale scaffold and exemplify sugar grafted nanofibrils as novel and effective tools in control of bacterial pathogenesis, bacterial removal as well as in many other applications.
Thursday
Intermission
04:45pm - 04:55pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 5
Division: [CELL] Division of Cellulose and Renewable Materials
Session Type: Oral - Virtual

Thursday
3653773 - Molecular mechanisms behind aging of cellulosic materials
04:55pm - 05:20pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 5
Division: [CELL] Division of Cellulose and Renewable Materials
Session Type: Oral - Virtual
While cellulose nanofibrils (CNF) have gained huge attention in recent years due to its wide potential and application in many fields of materials science, there is still a lack of understanding of the fundamental interactions between the fibrils under different conditions both in the wet state and in the dry state. These interactions are naturally of a much higher significance in the CNF-based materials, compared to macroscopic fibres, due to the high specific surface area of the CNF. This is indeed true for the hornification of cellulose-rich materials upon drying and the development of an understanding of the molecular mechanisms of irreversible changes in cellulose is naturally of relevance to any process where wetting and drying is a central step, but also in the making of functionalized cellulose-based materials.

The objective of the present work is to identify the interactions responsible for cellulose fibril aggregation upon drying and heating, also known as hornification.

In the present work we have executed extensive studies of irreversible joining of cellulose-rich surfaces by subjecting films of CNF and cellulose-based hydrogel beads to heat treatments for different times at different temperatures and measuring their re-swelling properties. The initial results indicate that the ageing can be described as a third order reaction for CNF in ionized form, but the molecular reactions behind this behaviour can naturally not be deduced form these measurements. It has also been observed that films from cellulose fibrils with different chemical composition, for example hemicellulose-rich CNF, show very different ageing kinetics.
Interestingly, an increase of up to approximately 36% in the reswelling degree of the model CNF films was observed after leaving them immersed in water for over a year. If a chemical reaction is neglected as the cause of the cellulose aggregation, it would suggest that the joining of cellulose-rich surfaces may be viewed as a kinetically locked state.

These swelling studies have also been combined with molecular and supra-molecular structural characterizations such as CP/MAS 13C-NMR and SAXS/WAXS on the differently aged model surfaces of cellulose to understand the link between structural changes and molecular interactions between these surfaces. Furthermore, differently treated films have been subjected to spectroscopic analysis, specifically multivariate FTIR, to analyse if any chemical changes can be established.

Thursday
3659188 - How does the nanostructure develops during assembly of nanocellulose filaments? OnDemand
05:20pm - 05:45pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 5
Division: [CELL] Division of Cellulose and Renewable Materials
Session Type: Oral - Virtual
Hydrodynamic assembly in flow channels can be used to assemble strong and stiff filaments from cellulose nanofibrils (CNF). In this process, flows in millimeter sized channels are used to first shape a low concentration CNF dispersion (3 g/l) into a thread, and then initiate a disp-gel transition to create a continuous gel thread that can be picked up and dried. One of the most important factors determining the properties of the final dry filament is the alignment and entanglement of the fibrils in the final filament. This structure is a combined result of the initial shaping by the flows followed by further structure development due to shrinkage during drying. We have combined experiments and simulations to obtain a complete understanding of how the nanostructure develops during the first stage of the assembly process. The flows are measured by Optical Coherence Tomograpy and modelled by computational fluid dynamics, and the fibril structure (in particular orientation) is measured by small angle X-ray scattering and modelled by a Smoluchowski equation using the calculated flow fields as an input. It is shown that excellent agreement between simulations and experiments can be obtained for both the flow and the fibril alignment if the polydispersity (in terms of fibril length) of the CNF is accounted for. The resulting model can be used to investigate and understand the full, 3D orientation state of the fibrils. Of particular interest are aspects such that variations over the thread cross section and the relative orientation between fibrils. The model reveals several key aspects of assembly of high performance filaments. A few examples are (i) where maximum alignment can be expected to occur (and thus, where one should aim to lock the fibril alignment via the disp/gel transition), (ii) how the fibril structure varies over the cross section for different operating conditions and (iii) how individual fibrils can be expected to be oriented relative to each other. The last point determines the initial stage for interfibrillar interactions during drying, and is therefore an important step between in-situ structure measurements and in-silico fibril interaction studies.
Thursday
3662112 - Marangoni flow manipulated concentric assembly of cellulose nanocrystals
05:45pm - 06:10pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 5
Division: [CELL] Division of Cellulose and Renewable Materials
Session Type: Oral - Virtual
Tunable assembly of Cellulose nanocrystals (CNCs) is important for a variety of emerging applications in optics, sensing and security. Most exploited assembly and optical property of CNCs are cholesteric assembly and corresponding circular dichroism (CD). However, it still remains challenge to obtain homogenous and high resolution cholesteric assembly. Distinct assembly and optical property of CNCs are highly demanded for advanced photonic materials with novel functions. Herein, we demonstrate a facile and programmable approach for assembling CNCs into a novel concentric alignment utilizing capillary flow and Marangoni effect, which is in strike contrast to conventional cholesteric assembly. The novel concentric assembly, as quantitatively evidenced by polarized synchrotron radiation FTIR imaging, demonstrates Maltese cross optical pattern with good uniformity and high resolution. Furthermore, this Maltese cross can be readily regulated to “on/off” states by temperature. By combining with 3D inkjet technology, a functional binary system composed of “on”/“off” CNCs optical patterns with high spatial resolution, fast printing speed, good repeatability and precisely controllable optical property is established for information encryption and decryption. This concentric assembly of CNCs and corresponding tunable optical property emerge as a promising candidate for information security, anticounterfeiting technology and advanced optics.
Figure. (a) Schematic illumination of concentric assembly of modified cellulose nanocrystals (M-CNCs). (b) Maltese cross optical property of concentric assembled M-CNCs films with low and high spatial resolution under linear polarized light. (c) Orientation analysis of M-CNCs from polarized synchrotron radiation FTIR imaging.

Figure. (a) Schematic illumination of concentric assembly of modified cellulose nanocrystals (M-CNCs). (b) Maltese cross optical property of concentric assembled M-CNCs films with low and high spatial resolution under linear polarized light. (c) Orientation analysis of M-CNCs from polarized synchrotron radiation FTIR imaging.


Thursday
3639355 - Tough PLA nanocomposites reinforced with cellulose nanofibrils using interface-engineered bridging and its application to CNFs aerogel template OnDemand
06:10pm - 06:35pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 5
Division: [CELL] Division of Cellulose and Renewable Materials
Session Type: Oral - Virtual
The conventional petroleum-derived plastics are not naturally degraded in a relatively short time and, therefore, cause growing accumulation of solid waste in the earth for decades or centuries causing serious environmental issues. Polylactic acid (PLA) has attracted extensive interests as one of the most ideal candidates to substitute petroleum-based plastics due to its sustainable properties such as biodegradability and non-toxicity. The major challenge to realize the commercial PLA-based product is attributed to its inherent brittleness. Here, we fabricate cellulose nanofibrils (CNFs)-reinforced PLA nanocomposites using a swelling-based particle adsorption (SPA) method which enables the CNFs to adsorb onto the PLA particles forming a core-shell structure. Compared to the neat PLA, the PLA/CNF composite films exhibit increased thermal stability, and mechanical toughness through an interfacial reaction between the CNFs and PLA matrix improving the inherent brittleness of PLA. We further apply this system to fabricate a CNFs aerogel by removing PLA matrix inside the resulting composite films. The CNFs aerogel exhibits superior mechanical properties due to the framework where the CNFs are interconnected throughout the CNFs networks. We provide the fabrication methods of CNF-based “green” bio-nanocomposites and CNFs aerogels with high mechanical performance, which facilitates their usage promising commercial prospects.
Thursday
Concluding Remarks
06:35pm - 06:40pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 5
Division: [CELL] Division of Cellulose and Renewable Materials
Session Type: Oral - Virtual

Virtual Graduate Students Symposium in Asia-Pacific Region on Current Environmental Issues:
05:00pm - 09:00pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Hongguang Guo, Organizer, Presider; Dr. Chun Zhao, Organizer, Presider; Chunxiao Zheng, Organizer
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual
Division/Committee: [ENVR] Division of Environmental Chemistry

This virtual symposium is initiated and co-organized by Southwestern China Chapter. The graduate students in Asia-Pacific region are welcome to showcase their most recent research on Environmental Chemistry and gain experience as oral speakers at an international setting. We will try to arrange all the presentations during day time in the region. The symposium will cover all aspects of Environmental Chemistry and in particular will focus on Water and Waste Water Treatment, Advanced Oxidation Processes, Emerging Contaminants and Environmental Nanotechnology.

Thursday
3637703 - Interpreting the impact of oil and gas surface return fluids (SRF) on soils using sequential extraction in Eddy and Lea Counties
05:00pm - 05:10pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Mary Adu-Gyamfi, Presenter
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual
Hydraulic fracturing (HF) is the injection of water, sand and chemicals into oil and gas reservoirs under high pressure to increase hydrocarbon production. The technology has caused a raise in production of oil and gas in the U.S. There is both environmental and human impact associated with this activity. But, research done so far, does not go far enough to identify all the potential risks involved. The extraction process for oil and gas generates more than 800 billion gallons of wastewater per year. This by-product contains salts and toxicants. The handling, disposal and treatment of the wastewater can accidentally or intentionally spill or leak onto soils. This research is aim at investigating the immediate and long-term impact of HF spills sobbed on soils using BCR sequential extraction method.

Sequential extraction techniques will be effectively employed to contaminated soil samples to provide information about the mobility and the availability of toxic metals such as Nickle, Chromium and Cadmium. The first step of the extraction will involve the exchangeable fraction using acetic acid to extract acid and water soluble metals. The second step will involve reducible-iron/manganese oxide using hydroxylammonium chloride to extract all the oxidizable metals. The third step will involve oxidizable-organic matter and sulfides with hydrogen peroxide to extract the remaining non-silica bound metals. The information obtained from this process will be used to further understand the possible risk and impact of the metals to humans and to the environment.

Thursday
3656124 - Specifically and visually detect aqueous Cr(III)-organic complexes based on cationic surfactant-modified Au nanoprobe
05:10pm - 05:20pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Ningyi Chen, Presenter; Bingcai Pan, Presenter
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual
Colorimetric detection of trace toxic metals in water based on gold nanoparticles (AuNPs) has been well demonstrated. However, almost all the available assays focus on free metal ions instead of metal-organic complexes, which are ubiquitous in real waters and more challenging for decontamination. Therefore, the specific analysis of metal-organic complexes has become an essential prerequisite for propelling the application of gold nanoparticles form laboratory study to real contaminated environment. In this study, we developed a novel colorimetric nanoprobe strategy for complexed Cr(III) species based on the analyte-induced aggregation of gold nanoparticles (AuNPs), as coated by a cationic surfactant tributylhexadecylphosphonium bromide (THPB) instead of traditional carboxyl modifiers. At alkaline pHs (pH=11), the unique hydrolysis and extremely slow decomplexation of Cr(III) is believed to form the specific interaction between Cr(III)-citrate and THPB-AuNPs and thereafter enhance the NPs aggregation, as verified by XPS, UV-Vis and Zeta potential. Such detection system could be realized via both naked eye and/or UV-Vis spectroscopy with the detection limit of 8.0 and 0.29 μM respectively, much lower than the total Cr toxic level regulated by Chinese environmental protection agency (EPA) (1.5 mg/L, ~30 μM). The proposed detection system also exhibits high selectivity against various interfering substances including free ions, small organic molecules and other metal-citrate complexes. Also, the THPB-AuNPs could be stored at room temperature for 30 days with the constant detection performance. Moreover, the quantitative detection of Cr(III)-organic complexes with the background of various real water samples agreed well with that based on ICP-AES, making it an attractive alternative for on-site detection of authentic samples containing Cr(III)-organic species.
Schematic illustration of colorimetric detection of Cr(III)-citrate based on THPB-mediated AuNPs

Schematic illustration of colorimetric detection of Cr(III)-citrate based on THPB-mediated AuNPs


Thursday
3655319 - Structure of bacterial communities in the upper layers of seasonally frozen soils on the Tibetan Plateau and the driving environmental factors OnDemand
05:20pm - 05:30pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
xiaojie wang, Presenter
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual
While soil microbes are most abundant and active in the top 10 cm layer, microbes in the soils below this layer also play important roles in many biogeochemical processes, which has not received much attention. This study investigated the variations in the diversity and composition of bacterial communities, especially the aerobic, facultative anaerobic, and anaerobic bacteria, in the upper layers of seasonally frozen soils on the Tibetan Plateau, and explored their driving environmental factors. A total of 135 soil samples were collected from the soils at depths of 0-10, 10-20, and 20-30 cm at 15 sites, and the diversity and composition of bacterial communities in them were identified by high-throughput 16S ribosomal RNA gene sequencing. Bacterial community diversity changed significantly with soil depth in the Nyang River basin (p < 0.001), while no obvious changes were found in the Lhasa River basin. The composition of bacterial communities exhibited small variations in different soil layers (p > 0.05), with Proteobacteria, Acidobacteria, Actinobacteria, and Chloroflexi (in decreasing order) being the dominant phyla, Alphaproteobacteria, Actinobacteria, and Gammaproteobacteria (in decreasing order) being the dominant classes, and norank_c__Subgroup_6_norank, Sphingomonas, and RB41 (in decreasing order) being the dominant genera. The absolute abundance of the dominant aerobic bacteria decreased with soil depth, while the dominant facultative anaerobic and anaerobic bacteria did not show such trend. The composition of bacterial communities was significantly affected by edaphic factors and biotic attribute. Structural equation modeling revealed that climatic factors, including mean annual temperature and mean annual precipitation, had direct and indirect impact on the diversity and composition of soil bacterial communities through shaping soil pH and vegetation. These results provide insights on the diversity and composition of bacterial communities in the upper layers of seasonally frozen soils on the Tibetan Plateau and the environmental factors that shaped such structure.
Thursday
3655616 - Novel PEI@CSH adsorbents derived from coal fly ash enabling efficient CO2 capture from coal-fired power plants
05:30pm - 05:40pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Fan Qu, Presenter; Feng Yan, Presenter; Heijin Chen
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual
The solid amine absorption is considered to be the most promising technology for post-combustion CO2 capture in coal-fired power plants, but it still has problems such as high support synthesis cost and easy occurrence of CO2-induced chemical deactivation. Herein, we proposed a new environmentally friendly method, a calcium silicate hydrate (CSH) support with a pore volume of 3.0 cm3 g-1 derived from coal fly ash (CFA) was synthesized by solution precipitation with the assistance of azeotropic distillation, and then the CO2 adsorbents were prepared by impregnating polyethylenimine (PEI) into the pores of CSH, which also realized the in-situ utilization of CFA while achieving CO2 emission reduction from coal-fired power plants. The adsorption capacity of the prepared 60%PEI@CSH-0.1 could reach 197.9 mg g-1 and exhibited good cycle stability of only 1.68% attenuation after 10 cycles under inert gas desorption conditions. Even under realistic desorption conditions (at 150°C under 100% CO2), there was still an adsorption capacity of 94.19 mg g-1 after 10 cycles, which showed obvious advantages compared with commercial SiO2 supports (67.06 mg g-1). It has been confirmed that the CSH support promoted the conversion of primary amines to secondary amines in PEI molecules, and effectively inhibited the inactivation caused by the formation of urea linkages. Therefore, the PEI@CSH adsorbents provides a promising low-cost and high-efficiency way for post-combustion CO2 capture.
Thursday
3646975 - Role of trade in India’s rising atmospheric mercury emissions
05:40pm - 05:50pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual
India is among the top global emitters of anthropogenic atmospheric mercury (Hg). Its Hg emissions have been projected to continue increasing in the coming years, contributing a greater share to global emissions. India’s rapid economic development and growing position in the global economy necessitates an assessment of how its Hg emissions are linked to domestic and global supply chains. Existing studies on India’s Hg emissions have focused on direct emissions from sources. However, several studies on China and the global context have emphasized the role of trade as a driver of Hg emissions. In this study, newly constructed national Hg emission inventories for four years (2004, 2007, 2011 and 2014) are linked to a global Environmentally-Extended Multi-Regional Input-Output model in order to identify the consumption-based and income-based drivers of emissions. India's Hg emissions increased from 84 tons in 2004 to 189 tons in 2014. Domestic final demand is found to be the dominant driver of India’s Hg emissions from the demand perspective, driving about 80-85% of the total. Similarly, from the supply perspective, domestic primary inputs are the dominant drivers, however, the share of foreign inputs causing India’s Hg emissions increased from 16% to 23% during 2004-2014. USA, China and UAE were found to be the top foreign consumption-based drivers, whereas top foreign income-based drivers include Saudi Arabia, Indonesia, Australia and China. Among economic sectors, the Construction sector is important as a demand-side driver, while sectors related to electricity, use of Hg containing dental amalgam and products, industrial activities, and trade are significant from both perspectives. Fossil fuel sectors are additionally important as supply-side drivers. We find that domestic supply chains must be prioritized for controlling India’s Hg emissions. Nevertheless, opportunities in international collaboration for capacity building and funds transfer must be promptly sought. These findings can guide global and national policies for demand- and supply-side management of India’s Hg emissions. They can assist in the successful implementation of the Minamata Convention on Mercury in India.
Thursday
3649188 - Wastewater surveillance for 168 pharmaceuticals and metabolites in a WWTP: Occurrence, temporal variations and feasibility of metabolic biomarkers for intake estimation
05:50pm - 06:00pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual
Wastewater-based epidemiology (WBE) has been widely applied to mining information about public health. Most of the WBE studies focused on illicit drugs and psychoactive compounds, and some researchers expanded WBE method to exposure or health level assessment. Proper biomarker selection is critical to get reliable substance consumption/intake estimation using WBE. This study measured a broad range of pharmaceuticals and metabolites in a wastewater treatment plant in Beijing, China and evaluated their suitability as consumption biomarkers. Wastewater sampling was conducted during a normal week and two holiday weeks to assess the impact of the holiday on population normalized daily mass loads (PNDL). 149 out of 168 pharmaceuticals and metabolites were detected, with 94 analytes being quantified in all sampling events. Digestive drug cimetidine and anabolic steroid trenbolone were only detected during holiday weeks. Population normalized daily load of some substances showed disparities between weekdays and weekends during the normal week. This study proposed a framework to diagnose whether a parent compound or its metabolite is suitable to apply for intake/prevalence rate estimation. It shows that not all the metabolites can be employed as biomarkers for back-calculation when in-sewer stability of these compounds is not clear, such as metoprolol acid and O-desmethyl venlafaxine. Public healthcare data for drug utilization were applied to validate the prevalence of average substance use in this study. WBE study illustrates the changes in drug use and population lifestyle that stem from holidays and commutes. In addition, it can provide data support for the selection of more suitable biomarkers in WBE studies.
Thursday
Discussion
06:00pm - 06:05pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual

Thursday
Intermission
06:05pm - 06:20pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual

Thursday
3657964 - Algae growth response to mixture of emerging organic contaminants
06:20pm - 06:30pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Jian Chen, Presenter
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual
Co-existing at trace concentrations in environments is the universal feature of emerging organic contaminants (EOCs), including pharmaceuticals and personal care products, pesticides, perfluorinated compounds. Although past efforts to understand the biota response to single EOCs have been considerable and well documented, their response to EOC mixture at environmentally relevant concentrations remain largely unknown. Here, we conducted 5720 observations to explore the response of population growth of two common algae along the gradient of EOC number (up to 100, 13 categories). We found that algal growth was simulated, inhibited or unaffected under single EOC treatments, but significantly inhibited under EOC mixture treatment and the inhibition increased with the number of EOCs. We developed a Bayesian-neural-network model to predict the algae growth rates as a function of the random EOC generated from a pool of the 100 EOCs. Both under different lab conditions and under ~111 U.S. natural lakes, we all observed a general concave-down relationship curve between EOC number and algae population growth, illustrating by a proposed “redundancy mechanism” within EOC interaction. Our findings highlighted the importance of management for EOC discharges and advance of green chemistry to ensure the sustainability of algae ecological services in the face of global EOC cocktails.
Thursday
3638000 - Algae biofilm mitigates the formation of microbe-derived dissolved organic nitrogen OnDemand
06:30pm - 06:40pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual
Conventional activated sludge systems are prone to produce microbe-derived dissolved organic nitrogen (mDON), which can readily induce harmful phytoplankton blooms after discharging with the effluent. Algae biofilm (AB) is an attractive substitution of activated sludge for its advantages in nutrient recovery. Here, we found that AB can attenuate the de novo formation of mDON by 83% compared with the sludge-based pre-denitrification process and consume sludge-derived mDON by at least 72%. AB reduced the amount of protein/amino sugar-like compounds and produced higher fractions of unsaturated hydrocarbon and lignin analogs, resulting in the low bioavailability of residual mDON. Genome-centric metagenomics revealed that cyanobacteria enabled the algal-bacterial symbiosis higher genetic potentials in mDON uptake, ammonification, and recycling, which could contribute to the mDON scavenging. Our findings demonstrate AB as a promising technology to reduce mDON discharges, which has implications for eutrophication control.
<b>Figure 1</b> The performance of the reactors in total dissolved nitrogen removal (a) and mDON (b) formation or removal. Molecular compositions of AB<sub>1</sub> vs. AS (c) and AB<sub>2</sub> vs. AS (d). The association of the microbial community and the nitrogen profile.

Figure 1 The performance of the reactors in total dissolved nitrogen removal (a) and mDON (b) formation or removal. Molecular compositions of AB1 vs. AS (c) and AB2 vs. AS (d). The association of the microbial community and the nitrogen profile.

<b>Figure 2</b> Comparisons of nitrogen acquisition and metabolism between algae biofilm (AB) and activated sludge (AS). The colors of the bar plots indicate the hosts of corresponding functional genes at the phylum level.

Figure 2 Comparisons of nitrogen acquisition and metabolism between algae biofilm (AB) and activated sludge (AS). The colors of the bar plots indicate the hosts of corresponding functional genes at the phylum level.


Thursday
3655293 - Sustainable micro-activation of dissolved oxygen driving pollutant conversion on Mo-enhanced zinc sulfide surface in natural conditions OnDemand
06:40pm - 06:50pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual
The activation of inert oxygen (O2) often consumes enormous amounts of energy and resources, which is a global challenge in the field of environmental remediation and fuel cells. Organic pollutants are abundant in electrons and promising as alternative donors. Here, we implement the sustainable micro-activation of dissolved oxygen (DO) by using the electrons and adsorption energy of pollutants through creating nonequilibrium micro-surface on nanoparticle-integrated molybdenum lattice-doped zinc sulfide composites (MZS-1). It is found that organic pollutants can be quickly removed by DO micro-activation in the MZS-1 system under natural conditions without any additional energy and electron donor. The turnover frequency (TOF, per Mo atom basis) is 5 orders of magnitude higher compared to homogeneous systems. Structural and electronic characterization technologies reveal the change in crystalline phase (Zn-S-Mo) and the activation of the π-electrons on six-membered rings of ZnS after Mo doping, which resulting in the formation of nonequilibrium micro-surface on MZS-1. It is the key for the strong interfacial interaction and directional electron transfer from pollutants to MZS-1 through delocalized π-π conjugation effect and from MZS-1 to DO via Zn-S-Mo, as demonstrated by electron paramagnetic resonance (EPR) techniques and density functional theory (DFT) calculations. This process achieves the efficient use of pollutants and the low-energy activation of O2 through the construction of nonequilibrium micro-surface, which shows new significance for water treatment.

Thursday
3659053 - Comparative analysis between full-scale A/A/O and A/O processes reveals the microbial roles in the transformation of dissolved organic matter
06:50pm - 07:00pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual
Understanding the degradation of dissolved organic matter (DOM) is vital for optimizing DOM control. However, the microbially mediated utilization and transformation of DOM in wastewater treatment plants remain poorly characterized. Here, microbes and the fate of DOM in full-scale anaerobic-anoxic-aerobic (A/A/O) and anaerobic-aerobic (A/O) processes were characterized using high-resolution mass spectrometry and genome-resolved metagenomics. Findings show distinct molecular compositions of effluent DOM between different processes, with more lignin- and tannins-like substances in A/O while more condensed aromatics-like compounds in A/A/O. In conjunction with the comparisons between A/A/O and A/O microbiomes, the properties (e.g., biodegradability) and compositions of DOM were found highly correlated to microbes. Furthermore, co-occurrence network analysis demonstrated that bacteria in different functional guilds showed different associations to specific DOM. Module hubs representing the keystone species in each functional guild were mainly affiliated with Bacteroidota, Chloroflexota, and Actinobacteriota. They were generalists in DOM transformation and responsible for the increased humification in the effluent. In contrast, microbial connectors were dominated by Gammaproteobacteria, Myxococcota, and Acidobacteriota. They were more specialized in DOM utilization and facilitated community-wide carbon cycling. This study highlights the different roles of microbes in DOM transformation and provides a fundamental for developing optimal DOM control strategies.
<b>Figure 1</b> The comparison of dissolved organic matter (DOM) composition between A/A/O and A/O

Figure 1 The comparison of dissolved organic matter (DOM) composition between A/A/O and A/O

<b>Figure 2</b> Co-occurrence network of metagenome-assembled genomes (MAGs) and dissolved organic matter (DOM)

Figure 2 Co-occurrence network of metagenome-assembled genomes (MAGs) and dissolved organic matter (DOM)


Thursday
3647393 - Transmission of plasmid across clinic and environment contributes to ARG propagation OnDemand
07:00pm - 07:10pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Dr. Xiaolong Wang, Presenter
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual
External environments represent a vast repository of antibiotic resistance and have been proposed as a reservoir of resistance genes available for exchange with clinical pathogens. However, plasmid, as one of the most important vectors of antibiotic resistance genes (ARGs), the predominant plasmidic ARGs propagation mechanisms across environment and clinic are not fully understood. Here, transmission of plasmid as well as plasmidic ARGs across environment and clinic were rigorously investigated by performing a genomic analysis of a large complete plasmid genome collection. Many more ARGs were enriched in clinically-relevant conjugative resistance plasmids compared with that isolated from environmental sources, which could be attributed to higher horizontal gene transfer (HGT) frequency of plasmidic ARGs in the clinic. Additionally, transmission of plasmidic ARGs across clinic and environment was also observed, exhibiting lower HGT frequency than that within clinic or environment. Among HGT events across environment and clinic, IS (insertion sequence), especially for IS26, was of importance to disseminate ARGs among clinically-relevant pathogens (i.e., Escherichia coli, Klebsiella pneumoniae, Salmonella typhimurium, etc.) between these ecological boundaries. Therefore, this study informs the One Health perspective to develop effective strategies that curtail plasmid-borne antibiotic resistance propagation.
Thursday
3648952 - Formation of dichlorine monoxide by free chlorine in high chloride-containing water
07:10pm - 07:20pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual
Dichlorine monoxide (Cl2O) is an overlooked but highly reactive free chlorine species that can degrade the recalcitrant organic pollutants in water. The on-site generation of Cl2O demands high energy and safety measures. The production of aqueous Cl2O in freshwater has been theoretically estimated to be at practically irrelevant free chlorine concentrations of a few hundred mgCl2/L. In this study, we reveal that several ppm levels of free chlorine in high chloride-containing solutions of no less than 0.20 M form significant concentrations of Cl2O and show remarkably high degradation rate constants towards a persistent micropollutant, carbamazepine (kCBZ). A new Cl2O formation mechanism is proposed, in which chloride transforms HOCl/ClO- to Cl2 and reacts with Cl2 to form polychloride monoanions to assist in the transformation of Cl2 to Cl2O in the presence of HOCl/ClO-. The generation of Cl2O increases by about 60 times with decreasing pHs from 7.50 to 4.33, mainly because of the increase in the Cl2 formation. Weak acid anions, i.e., phosphate and bicarbonate, are stronger nucleophiles which assists the hydrolysis of Cl2O, but their presence does not affect much of the Cl2O concentrations or kCBZ at near neutral pHs. The formed Cl2O reacts faster with aromatic pollutants connected to more electron-donating functional groups, i.e., hydroxyl > amine>methoxy >> carboxyl groups. The new Cl2O formation mechanism reveals the critical role of chloride in assisting the Cl2O formation, providing the possibility to make use of Cl2O to degrade recalcitrant organic pollutants in high chloride-containing wastewaters. It may also profoundly change our understanding of the speciation of different free chlorine species and their impacts on the DBP formation in high chloride-containing wastewaters.
Thursday
Discussion
07:20pm - 07:25pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual

Thursday
Intermission
07:25pm - 07:40pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual

Thursday
3640335 - Sequential and combined use of UV-LEDs irradiation and chlorine to disinfect waterborne fungal spores: Efficiency, mechanism and photoreactivation
07:40pm - 07:50pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual
Waterborne fungi have been recognized as an emerging environmental contaminant in recent years. In this work, sequential and combined applications of light-emitting diodes (UV-LEDs) with two wavelengths and chlorine (Cl2) were performed for fungal spores disinfection, the performance of LPUV (low pressure ultraviolet) and UV-LEDs was also compared. The results revealed that inactivation efficiency of fungal spores in the UV/Cl2 process was greatly enhanced compared to the sequential or individual processes, and an evident synergistic effect was observed. Take P. polonicum for example, pre-treatments by UV265 and UV280 (40 mJ/cm2) caused the log count reduction (LCR) of 1.05 log and 0.95 log, then the followed UV265/Cl2 and UV280/Cl2 at the same UV fluence caused additional LCR of 1.80 log and 2.00 log. The inactivation rates for Penicillium polonicum in the processes of UV265/Cl2, UV280/Cl2, UV265/280/Cl2 and LPUV/Cl2 was 0.142, 0.168, 0.174 and 0.106 cm2/mJ, respectively, which were all approximately 1.5-fold higher than that of UV alone. The synergistic effect of fungal spores inactivation by UV-LEDs/Cl2 and LPUV/Cl2 was due to the high level production of intracellular reactive oxygen species and the reaction of potential extracellular free radicals. Resistance of the tested fungal spores was as follows: Trichoderma harzianum < Penicillium polonicum < Aspergillus niger. In addition, the joint effect of DNA and other cellular damage resulted in the inhibition of photoreactivation of fungal spores inactivated by UV-LEDs/Cl2 and LPUV/Cl2. This study may provide reference for controlling the dissemination of waterborne fungi utilizing combined UV-LEDs and free chlorine processes.

Thursday
3648764 - Efficiency and mechanism of UV/chlorine process in the disinfection of Pseudomonas aeruginosa in drinking water
07:50pm - 08:00pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual
Disinfection is essential for the inactivation of pathogens and prevention of waterborne diseases in water treatment, particularly during the COVID-19 pandemic. Both UV irradiation and chlorination have been widely used for water and wastewater disinfection. However, there are some shortcomings, such as the occurrence of viable but nonculturable (VBNC) bacteria and the reactivation of bacteria when using UV or chlorination alone. Thus, the feasibility of the UV/chlorine combined process in drinking water disinfection was comprehensively assessed in this study and Pseudomonas aeruginosa was selected as the target microorganism. The inactivation of culturable bacteria were more than 5-log10 after UV, chlorination and UV/chlorine treatments. However, intact cells were detected at 103~104 cells/mL after UV and chlorination alone, whereas they were undetectable after UV/chlorine process due to the contribution of reactive chlorine species (Cl*, Cl2*–, ClO*). The metabolic activity after UV/chlorine combined process determined by single cell Raman spectroscopy was much lower than that after UV. The concentration of toxic opr gene in P. aeruginosa reduced by more than 99% after UV/chlorine combined process. More importantly, dark reactivation of bacteria was completely suppressed by UV/chlorine but not UV or chlorination. This study suggests that UV/chlorine combined process can completely inactivate bacteria and is promising for pathogen inactivation to overcome the limitations of UV and chlorination alone.
Thursday
3656279 - Novel Ti/CB@MXene anode for electrochemical oxidation of refractory 5-chloro-2-methyl-4-isothiazoline-3-ketone as a fungicide in brine of reverse osmosis OnDemand
08:00pm - 08:10pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Xiaomeng Shang, Presenter
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual
In this study, a novel Ti/Carbon Black (CB) @MXene anode used in electrochemical oxidation for water purfication was fabricated firstly, then this electrochemical oxidation technology was used to degrade 5-chloro-2-methyl-4-isothiazoline-3-ketone (CMIT) as a kind of fungicide in brine of reverse osmosis. According to XRD, SEM and electrochemical test (EIS, CV, LSV) characterization, this novel anode showed slippy surface, suggesting it is hard to be fouled. The high oxygen evolution potential, lower resistance and better electric conductivity made this anode exhibited higher current utilization than other regular anodes, due to less effect of the side reaction. The best mass ratio of Ti3C2Tx and CB was 1:1, because the combination showed highest oxygen evolution potential. The reaction parameters including current density and plate spacing were optimizied as 5.625 mA/cm2 and 1.0 cm, where the best CMIT degradation efficiency was 89.86% and energy consumption was 831.14 kW h/kg. This performance was better than DSA anode and similar with BDD. Importantly, when using Ti/CB@MXene anode, less active chlorine was formed than using DSA or BDD anode, so less chlorine by-products may be produced and has lower toxicity. By radical quenching experiment, the indirect oxidation dominated CMIT degradation as 99.69% and hydroxyl radical exposure is 2.69×10-9 mol/L s which was approximately 3762.24 fold higher than that of traditional Ti anode. According to LC-Q-TOF-MS analysis, three possible degradation pathways of CMIT were proposed, as below: the electron rich sulfur in S-N bond was oxidized to form sulfoxide structure, chlorine was replaced by hydroxyl radical, olefin double bond on the five-member heterocyclic ring was attacked by hydroxyl radical. The ecotoxicity of the intermediate products were evlauted by ECOSAR, electrochemical oxidation with this novel anode decreased the ecotoxicity. This novel Ti/CB@MXene anode showed better potential in electrochemical oxidation for refractory organics degradation in brine of reverse osmosis.
Thursday
3656226 - Research on the exposed surface and electron transfer medium of nanomaterials for enhanced sunlight photocatalytic water decomposition
08:10pm - 08:20pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Xue Ma, Presenter
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual
With high surface energy leading to high photocatalytic activity, there have been significant interests in maintaining a high surface energy of the photocatalyst by controlling its exposed facet. To demonstrate the effect of exposed facet on the performance of composite photocatalyst and understand the corresponding mechanism, we prepared Ag3PO4 with {111}, {110}, {100}, mixed exposed facets, and constructed corresponding Z-scheme Ag/ZnFe2O4-Ag-Ag3PO4 heterojunctions for photocatalytic H2O2 production. ZnFe2O4 and Ag3PO4 with different exposed facets were synthesized, while Z-scheme Ag/ZnFe2O4-Ag-Ag3PO4 composites were prepared using a photo-assisted isoelectric point method. The {111} facet of Ag3PO4, which has higher surface activity, better separation efficiency of photogenerated e and h+, and higher energy and activity of photogenerated electrons, exhibited the highest activity in H2O2 production under simulated sunlight. In addition, the transfer rate of photo-generated electrons is also a critical factor that determines the photocatalytic efficiency of Z-scheme photocatalystic systems. A novel Z-scheme g-C3N4-AQ-MoO3 photocatalyst with anthraquinone (AQ) as an e transfer channel for hydrogen production was proposed. The enhanced photocatalytic activity of the composite is due to the accelerated transfer of e in the form of charge inside AQ, which also suppresses the recombination of photo-generated e and h+. In addition, the reduction area is significantly increased by the exfoliation of g-C3N4 into thin layers. As a result of the synergistic effect of rapid e transfer and large reduction area, the Z-scheme g-C3N4-AQ-MoO3 has a high hydrogen production efficiency.
Thursday
3653878 - Photocatalytic transformation fate and toxicity of ciprofloxacin related to dissociation species OnDemand
08:20pm - 08:30pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Taobo Huang, Presenter
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual
The photodegradation kinetics, transformation products and degradation pathways of CIP with different dissociation species (cations, zwitterions and anions) were investigated in photocatalytic system. Based on DFT calculation, Fukui index interpreted the active sites of different CIP species, and potential energy surface further elucidated the reaction transition state evolution for the radical attack (hydroxyl radical). Zwitterionic form of CIP exhibited the highest pseudo-first order rate constant (0.2217 ± 0.0179 min-1) during photocatalytic degradation. Combining the analysis of high performance liquid chromatography-mass spectrometry and DFT calculation, cationic and anionic CIP mainly experienced the cyclodealkylation of piperazine, while zwitterionic CIP mainly experienced the defluorination and epoxidation of piperazine. Toxicity evaluation showed that most of the transformation intermediates/products decomposed by defluorinated and hydroxylated CIP had low risk to aquatic organisms.
Thursday
3643535 - Withdrawn
08:30pm - 08:40pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual

Thursday
Discussion
08:40pm - 08:45pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual

Thursday
Concluding Remarks
08:45pm - 09:00pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 10
Division: [ENVR] Division of Environmental Chemistry
Session Type: Oral - Virtual

Virtual Graduate Students Symposium in Asia-Pacific Region on Polymer Chemistry:
05:00pm - 09:00pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 11
Yanli Feng, Organizer, Presider; Jia Tang, Organizer, Presider; Chunxiao Zheng, Organizer
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Virtual
Division/Committee: [POLY] Division of Polymer Chemistry
Thursday
3653117 - Highly branched polymethacrylates prepared efficiently: Brancher-Directed topology and application performance
05:00pm - 05:15pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 11
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Virtual
Highly branched polymers are promising for various applications, due to their divergent three-dimensional globular structure and the large number of terminal functionalities. Atom transfer radical polymerization (ATRP) provides a powerful tool for the synthesis of polymers with almost perfect control over molecular weight and topology. A series of highly oil-soluble and branched polymethacrylates are synthesized efficiently via atom transfer radical copolymerization (ATRcP) of methacrylate with a small amount of divinyl brancher, focusing on the brancher effect on the polymer structure and its application performance as lubricant additives. Structural characterization and performance testing for these polymers as lubricant viscosity index improvers and pour point depressants are performed. The results indicate that branched polymers containing X-like crosslinkages exhibit good viscosity thickening capacity and excellent shear stability, while those with T-like crosslinkages are able to significantly decrease the pour point and cloud point of lubricant.

Thursday
3653475 - Hybrid olefin metathesis polymerization
05:15pm - 05:30pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 11
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Virtual
Olefin metathesis catalysts are well-known for their versatility of catalyzing different mechanisms including ring-opening metathesis, ring-closing metathesis, and cross-metathesis. The combination of different olefin metathesis reactions in a same polymerization affords the construction of complex but well-defined chain topologies and thus becomes an intriguing topic.
However, the mechanistic differences between olefin metathesis reactions can bring mutual influence between different mechanisms and the influence could be hardly described. The understanding of the mutual influence between different olefin metathesis mechanisms is therefore crucial for the design of olefin metathesis polymerization with different mechanisms. In the present work, we utilize the theory of binary polymerization to assess the mutual influence between olefin metathesis mechanisms. The mutual influence can be characterized quantitatively via kinetic simulations. The relationship between the mutual influence of different olefin metathesis mechanisms and the effect of various parameters such as structure of the monomer, solvent, concentrations, etc. are carefully studied and used for the construction of polymers with various topologies including linear polymer, ring polymer, hyperbranched polymer, and bottlebrush polymer. This work demonstrates how to study the mutual influence between different polymerization mechanisms using the theory of binary polymerization and reveals the potential of combining different mechanisms with mutual influence in a same polymerization reaction.

Thursday
3655332 - Convenient synthesis of multicompartment block copolymer nanoparticles
05:30pm - 05:45pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 11
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Virtual
ABC triblock copolymers can form many complex structures due to the polarity difference of each block. In this study, triblock copolymer multicompartement nanoparticles of poly(N,N-dimethylacrylamide)-block-poly(tert-butylacrylate)-block-poly(4-vinylpyridine) (PDMA-b-PtBA-b-P4VP) and poly(N,N-dimethylacrylamide)-block-poly(tert-butylacrylate)-block-polystyrene (PDMA-b-PtBA-b-PS) with multicompartement structure were synthesized RAFT polymerization under dispersed condition, e.g., combined emulsion/dispersion polymerization or emulsion polymerization. In these multicompartement nanoparticles, the PtBA block forms the main body of the particle, and the P4VP or PS block forms the dispersed microdomains on the particle surface, which are completely different from the traditional core-shell nanoparticles of block copolymers. The formation of these multicompartement nanoparticles can be attributed to (1) poor compatibility between the PtBA block and the P4VP or PS block (2) the novel synthesis which ensures the P4VP or PS block to be kept dispersed. It is found that the morphology of the multicompartment nanoparticles is firmly dependent on the degree of polymerization (DP) of the third block of P4VP or PS, and the size of the dispersed microdomains becomes larger with the increasing DP of the P4VP block. This study provides a convenient method for the synthesis of MCBNs.

Thursday
3655338 - Digital dendrimer: A novel type of digital polymer
05:45pm - 06:00pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 11
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Virtual
Digital polymers are applied for molecular data storage. Herein, a new conception of digital dendrimer is proposed, which possessing higher data storage capacity and novel properties based on maleimide motifs. For efficient data coding, a series of digital dendrimers are synthesized by divergent growth strategy via thiol-maleimide Michael coupling, which allows precise arrangements of the 0- and 1-bits in the uniform dendrimers. For reliable data decoding, a protocol for calculating the storage capacity of non-linear binary digital dendrimer is established based on data matrix barcode, generated by the tandem MS decoding. Furthermore, the generated data matrix barcode can be read by a common hand-held device to cater the applications such as item identification, traceability and anticouterfeiting purpose. Overall, this work demonstrates the high data storage capacity of a uniform digital dendrimer and uncovers novel applications for the digital polymers.

Thursday
3656023 - Controlled disassembling of elemental sulfur: A new approach to the precise synthesis of poly(disulfide)s OnDemand
06:00pm - 06:15pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 11
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Virtual
Elemental sulfur, as one of the additional products in petrochemical industry, can be directly used in the production of asphalt, sulfuric acid and other chemical products, but still causes a large surplus and the corresponding storage and transportation problems. Conversion of elemental sulfur into high value-added products, such as sulfur-containing polymers, is currently a solution to resource utilization of elemental sulfur. Poly(disulfide)s as one of the most important sulfur-containing polymers, are widely appealed in the areas of Li-S batteries, self-healing materials and vitrimers. Compared with the drawbacks of uncontrolled molecular weight and the distribution of the resultant polymers or the limited diversity of cyclic disulfide-containing monomers, we are to present a novel strategy for synthesizing poly(disulfide)s with well-defined structure by ring-opening copolymerization with high-efficiency by elemental sulfur and episulfides. In this context, overcomeing the drawbacks of the conventional method of preparing poly(disulfide), organic base MTBD (the abbreviation of 7-Methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene) is capable for transformation of elemental sulfur and a quaternary ammonium salt with a non-nucleophilicity anion(PPNSbF6) is efficient for facilitating the [MTBD]+–Sx disassembling into a [MTBD]+–S species, therefore give the disulfide linkage for further ring-opening of episulfides. So, we provide a fresh thinking of the mild and controllable reaction condition which suitable for a variety of monomers to produce poly(disulfide) with definite structure for the unique potential in lithium sulfur batteries, self-healing materials and heavy metal ion absorption.

Thursday
3656371 - Living polymerization of acrylates catalyzed by a thermal- and bench-stable organic borane/phosphine Lewis pair
06:15pm - 06:30pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 11
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Virtual
Lewis pair polymerization (LPP) has emerged as a powerful tool for the efficient polymerization of polar vinyl monomer owing to synergistic/cooperative monomer activation by both Lewis acid (LA) and Lewis base (LB) sites of Lewis pair (LP) catalyst. However, LP catalysts for controlled/living LPPs of polar vinyl monomers reported to date are all required metal LAs with high oxophilicity, which are not only highly sensitive to air/moisture and heating, but also would compromise of product performance and applications due to metal residue in final polymers. Here, we report the development of a robust LP organic catalyst based on tris(2,4-difluorophenyl)borane and triisobutylphosphine, which not only renders efficient and living LPP of acrylates for the first time at ambient or even industrially relevant temperature (60-80 oC), but also unprecedentedly allows the polymerization under an open-air condition. All polymerizations show quantitative initiation efficiencies (I* = 80~109.0%), producing the polymers with predicted number-average molecular weights (Mn up to 190.0 kg/mol) and unimodal narrow dispersity values (1.00~1.20). Taking advantage of living nature of this LPP, well-defined di-, tri-, and tetrablock acrylic copolymers have also been successfully synthesized via sequential monomer addition over a broad reaction temperature. The establishment of this robust organic LP demonstrates that it is possible to develop organic catalysis with thermal and air/moisture tolerance, precise controllability, and high catalytic efficiency via a rational design of the catalyst structure.
<b>Table of Contents</b>

Table of Contents


Thursday
3658040 - Controllable synthesis of sequence-regulated functional polymers based on renewable monomers
06:30pm - 06:45pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 11
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Virtual
The synthesis of sequence-regulated polymers remains a long-standing challenge in the field of polymer chemistry. Using living/controlled catalytic system, sequence-regulated polyester based thermoplastic elastomers (TPEs) and polar conjugated diene monomers based polymers with (AB)n sequence could be synthesized in controlled manner. Without the requirement of specific functionalized groups, TPEs consisting of poly(L-lactide) hard segments and poly(e-caprolactone)-co-p(d-valerolactone) soft segments are successfully synthesized with high stretchability (up to 2100%), strong tensile strength (up to 71.5 MPa), and super-toughness (445 MJ/m3) by simply adjusting microstructures of polymers. Systematic investigation reveals that the block-like, gradient microstructure not only improves ductility by providing flexible elastic network, but also enhances tensile strength through strain induced crystallization. In addition, Lewis pairs were applied for 1,4-selective polymerization of (E,E)-methyl sorbate (MS) and (E,E)-ethyl sorbate (ES). High catalytic activity and high initiation efficiency can be achieved, leading to the formation of PMS with 100% 1,4-selectivity, tunable molecular weight (Mw up to 333 kg/mol) and narrow MWD. Furthermore, simple chemical reactions can efficiently convert PMS to different polymers with strict (AB)n sequence structures, such as poly(propylene-alt-methyl acrylate), poly(propylene-alt-acrylic acid), poly(propylene-alt-allyl alcohol) and poly(ethylene-alt-2-butylene). Their material properties including thermal properties, surface properties and adhesion properties were investigated in details.

Thursday
3658641 - Osmosis-driven programmable soft actuator based on UCST&LCST janus hydrogel of P(MAA-co-DMAPS) OnDemand
06:45pm - 07:00pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 11
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Virtual
With the rapid development of artificial intelligence, more and more smart flexible materials have been applied to soft robots, and given these robots “senses” and “acts”. The most common option is stimulus-responsive hydrogel, especially thermo-responsive hydrogel featuring high water-content and excellent biocompatibility. However, low response rate and strong dependence on water environment enable them to be greatly limited in practical use for soft sensors and actuators. So we adopted poly(methacrylic acid-co-3-dimethyl (methacryloyloxyethyl) ammonium propanesulfonate) (PMAA-co-DMAPS) to construct a novel UCST&LCST Janus hydrogel for osmosis-driven programmable soft actuator. Particularly, PMAA-co-DMAPS copolymers with different monomer ratios display huge transition between upper critical solution temperature (UCST) and lower critical solution temperature (LCST). Once integrated into one, reverse thermo-responsive capability will contribute to increase response rate of the Janus hydrogel. And single material source also favor enhancement on inherent compatibility to realize internal water circulation. Within 45 minutes, the Janus hydrogel underwent a large bending angle of 960° from 385° to -575° as the ambient aqueous phase was heated up from 10 to 50 oC. The results of microscopic morphology and ion penetration testing showed that, heat can induce obvious transition of porosity and density, and then make water molecules exchanged through the bonding interface between the UCST and LCST side. It is anticipating to leave the Janus hydrogel from aqueous environment and broaden their applications.

Thursday
3642167 - Flexible bioelectronics for precise health management
07:00pm - 07:15pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 11
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Virtual
Flexible bioelectronics, integrated into a variety of accessories, seamlessly fitting to the skin, or even implanted in the living body, have been extensively researched and have made great progress in biomedical fields such as electronic skin, intelligent monitoring and human-machine interface. In particular, a significant interest of flexible bioelectronics lies in monitoring physiological signals, revealing timely information on the state of our body and further providing actionable feedback for disease treatment to sustain a healthy lifestyle. However, the device power source still faces the limitation of large size, rigidity and short working life. If wearable electronic devices can be attached to a living body to collect energy generated by low-frequency motion and directly drive a flexible smart biomedical device, the nonnegligible problem of the size, rigidity and working life can be solved.

Here, we present a novel symbiotic non-pharmacological therapy system through low-invasive electrical intervention methods, including a wearable hair regeneration device, an implantable weight loss device and a biodegradable tissue repair device, emphasizing their role in biomedical applications in vivo and problems in practical applications. The work of weight loss provides an efficient and low-invasive strategy, and the weight of the device-implanted rat group was reduced by ~40% compared with the control group. A closed-loop feedback regulation system through food intake, gastric motion, electrical neuromodulation and brain control was established. Meanwhile, in the experiments of hair regeneration and tissue repair, the non-pharmacological electrical stimulation can regulate secretion of multiple growth factors, promote cell proliferation, and ultimately achieve the efficient repair effect. In general, due to the non-pharmacological and low-invasive nature, the widespread application of symbiotic bioelectronics will effectively treat more diseases or symptoms.

Thursday
3645977 - Platinum-containing drug-based supramolecular polymer realizing self-tracking in tumor
07:15pm - 07:30pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 11
Chengfei Liu, Presenter
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Virtual
Supramolecular drug self-delivery systems involving active drugs as building blocks linked by supramolecular interactions have been well defined as an advanced chemotherapy strategy. However, the lack of real-time feedback on drug release at tumor sites inevitably leads to unsatisfactory therapeutic effects, owing to the lack of information regarding the administration of these drugs. In this work, we designed platinum-containing drug-based supramolecular polymer (PtSPD) based on the host-guest interactions of two functionalized drug molecules cisplatin and gemcitabine. Then, PtSPD further self-assembled into platinum-based supramolecular micelles (PtSMs) in aqueous solution. The obtained PtSMs could be timely monitored by computed tomography imaging, immediately reflecting the evolution of drug release and real-time treatment at the tumor site. The appropriate administration about drug dosage and injection interval (1.2 mg mL−1, 100 μL, once every 3 days) could be precisely defined according to the therapeutic feedback. Therefore, the Pt-based self-tracked PtSPD may offer new potential opportunities for application in the field of efficient synergistic chemotherapy.

Thursday
3649304 - Improving stability and oral bioavailability of Amphotericin B by prodrug approach and pH-sensitive nanocarrier-mediated drug delivery
07:30pm - 07:45pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 11
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Virtual
Background: Amphotericin B (AmB) is an effective anti-fungal and anti-leishmanial drug. But because of its unfavorable physicochemical properties, no commercial product is available for oral delivery to date. Novel drug-lipid conjugation would increase the drug’s solubility/permeability and reduce toxicity. Further, developing pH-sensitive liposomes would result in intestinal drug delivery.

Procedure: The AmB was first conjugated with tocopherol succinate (TOS) and further developed into liposomes by thin film hydration method. They were then coated with Eudragit S-100 to protect from harsh G.I. environment. The in vitro drug release studies were performed in simulated gastric fluid and simulated intestinal fluid. Ex-vivo intestinal permeability study was conducted on excised goat intestinal tissue. Further, the safety of the formulations was evaluated on Caco-2 cells and finally, the pharmacokinetic studies were carried out.

Results: The uncoated liposomes possessed particle size of about 147±19 nm and PDI value 0.387±0.01. Upon coating, the particle size was found to be much higher (428±23 nm). In vitro drug release study showed a significant retardation of drug release from AmB-TOS coated liposomes [(Fig. 1(B)]. The percentage cell viability of the coated liposomes was found to be >90% [(Fig. 1(C)]. The intestinal permeability of the conjugate was found to be the highest followed by those of coated liposomes and free drug [(Fig. 1(D)]. The pharmacokinetic study further revealed 2.41-, 2.35-and 1.5-folds increase in AUC, t1/2, and MRT as compared to free drug.

Conclusions: In nutshell, this system could be effectively explored for designing oral formulations of AmB.
<b>Fig. 1. </b>Characterization results of AmB, AmB-TOS, AmB-TOS liposomes (AmB-TOS-L) and AmB-TOS coated liposomes (AmB-TOS-CL). (A) TEM images of (I) AmB-TOS-L, and (II) AmB-TOS-CL, (B) drug release pattern, (C) % cell viability at varying concentrations, and (D) apparent permeability data of the different formulations.

Fig. 1. Characterization results of AmB, AmB-TOS, AmB-TOS liposomes (AmB-TOS-L) and AmB-TOS coated liposomes (AmB-TOS-CL). (A) TEM images of (I) AmB-TOS-L, and (II) AmB-TOS-CL, (B) drug release pattern, (C) % cell viability at varying concentrations, and (D) apparent permeability data of the different formulations.


Thursday
3655313 - Withdrawn
07:45pm - 08:00pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 11
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Virtual

Thursday
3658847 - Photoelectric-responsive liquid crystal elastomer for rapid, controllable, and reversible deformation OnDemand
08:00pm - 08:15pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 11
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Virtual
Liquid crystalline elastomers (LCEs) combine high anisotropy with good flexibility, and exhibits excellent stimuli-responsive capability and large shape transformations. Nowadays, LCEs have widely applied to soft robots, artificial muscle, smart coating and other emerging areas, owing to their outstanding performances. However, common stimulus (e.g. temperature and humidity) as switch or trigger, are slow and hard to control. Herein, a novel asymmetrically fluorine-substituted azobenzene dopant was designed and synthesized, and doped into the nematic liquid crystal matrix to construct photoelectric-responsive LCEs for precise control. Particularly, the rigid axis of the dopant does not fit with its polar axis, leading to negative dielectric anisotropy (Δε=-4.05). Naturally, the doped LCE also possesses good negative dielectric anisotropy (Δε=-1.49 at room temperature). As a direct current electric field with the field strength of 1 V/μm was applied, the obtained LCE flake bended 30° within 2 seconds. On the other hand, the LCE flake underwent rapid reversible deformation under ultraviolet and visible photoirradiation, which attributes to the photoisomerization of azobenzene group in the dopant molecules. Clearly, this dual-responsive LCE offers an outstanding and promising control strategy for smart soft matter.

Thursday
3661906 - Precise control of chain-walking polymerization: exclusive branch pattern, main-chain functionalization, block polymer OnDemand
08:15pm - 08:30pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 11
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Virtual
Late-transition metal chain-walking polymerization catalysts, because of their abilities to produce various branched polyethylenes (PE) from ethylene alone, were distinctively fascinating. Although numerous studies have been done so far, exploration of how to synthesize PE with desired and specific structure via chain-walking polymerization from ethylene is elusive.
In our works, we designed and synthesized a novel rigid chain-walking catalyst [Pd] that successfully produced ultra-highly branched PE with methyl branches (220 Me / 1000 C) exclusively from ethylene alone. However, higher temperature resulted in the decrease of not only branching degree but also selectivity of branches. In order to overcome it and fulfill superior control, we further synthesized a low-cost nickel (II) catalyst [Ni] that enabled the exclusive methyl branch pattern with an ultrahigh number (100 ~ 200 Me / 1000 C) over a particularly broad temperature range of 30 oC~ 90 oC that meets the industrial process.
Generally, due to the chain-walking process after polar monomer insertion, chain-end functionalization that polar group is at the chain-end of branches was the major result of copolymerization. Thus main-chain functionalization was hard to realize. In our works, we showed main-chain incorporation of polar monomer using [Pd], key to this strategy was the inverted regioselectivity of polar monomer insertion.
Block polymer is an important material in industry, in our works we demonstrated a one-pot reaction that produced block polymers with the sole feedstock of ethylene. Beyond temperature and pressure, we found a new and convenient additive to drastically switch the branching numbers in [Pd] promoted ethylene polymerization. Key features that a polar additive does not induce chain transfer (living mode, PDI < 1.10) readily enabled the preparation of diblock topologies. With polar monomer, functionalized block PE could be produced in the same way.

Thursday
3662210 - Polythioamides from multicomponent polymerizations of elemental sulfur, diynes, and aromatic diamines
08:30pm - 08:45pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 11
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Virtual
Sulfur-containing polymers are a group of fascinating materials and have attracted much attention recently, owing to their unique metal coordination ability, high refractive index, and rich redox chemistry, which have been applied in noble metal recovery, self-healing, optoelectronic devices, etc. However, the dominant factor restricting their development is the lack of efficient and economic synthetic methods. Multicomponent polymerizations (MCPs) have proved to be a powerful tool for rapidly converting simple monomers to complex polymer materials because of their great designability, structural diversity, simple procedure, and environmental benefit. Herein, we reported a series of multicomponent polymerizations of elemental sulfur, diynes, and aromatic diamines that achieve direct conversion from elemental sulfur to polythioamides. The MCPs went smoothly at 80 oC in dimethyl sulfoxide, which is also applicable to a range of different monomer structures, affording desired polymers with high yields (up to 97%) and high molecular weights (up to 58 400 g/mol). The resulting polymers are processable and enjoy high thermal stability, and their structures were carefully characterized through FT-IR, 1H, and 13C NMR. Inspired by the coordination between gold and thioamide moiety, the polythioamides were applied on the gold recovery from the e-waste, and exhibited efficient and selective removal performance, demonstrating a kind of promising excellent gold adsorbents.

Thursday
3662356 - Room temperature multicomponent polymerization of elemental sulfur, pyridyl-activated alkyne and aliphatic amines
08:45pm - 09:00pm USA / Canada - Pacific - March 24, 2022 | Location: Virtual 11
Lihui Zhang, Presenter; Sir Yang Hu, Presenter; Rongrong Hu, Presenter; Ben Zhong Tang, Presenter
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Virtual
The preparation of polythioamides through multicomponent polymerization involving elemental sulfur possesses several advantages such as simple procedure, wide monomer scope, catalyst free, and high atom economy. However, elevated temperature in previous work was indispensable on the synthesis of polythioamides. Herein, we designed highly active alkyne activated by electron-withdrawing unit to increase the reaction efficiency and reduce the polymerization temperature. Multicomponent polymerization of elemental sulfur, pyridyl-activated alkyne ,and aliphatic diamine was developed to afford different polythioamides with clear structures, high yield (98%) and high molecular weight (Mw = 35 400 g/mol) at room temperature without any catalyst. With the reaction temperature slightly increased to 40 °C, the molecular weight increased to 95 100 g/mol in high yield (98%), while the polythioamide with relatively low molecular weight (Mw = 59 100 g/mol) and yield (84%) synthesized from non-activated 1,3-diethynylbenzene required higher monomer concentration at higher temperature of 90 oC. Besides, with the introduction of pyridyl group into polymer backbone, the polythioamide obtained a higher enrichment efficiency with a lower mass ratio of polymer to mercury ions, owing to the coordination property of the pyridine group. Interestingly, the emission of both polythioamides and model compounds have blue shifts after being irradiated with 365 nm ultraviolet light for 30 minutes, which is a supplement and exploration on the luminescent property of the polythioamide systems.
TOC

TOC


Thursday
India Satellite Event - Pitch your Research: A Virtual Science Communication Competition
08:30pm - 02:30am USA / Canada - Pacific - March 24, 2022
Session Type: Poster - Virtual

An opportunity for Undergrad/Graduates/PhDs and Postdocs from India to present a bird’s eye view of their research to scientists, researchers, and science communicators, effectively explaining their research in three minutes. The competition aims at cultivating the presentation and science & research communication skills.

Compress your research project from a 20-minute presentation to 3 minutes.

Communicate your research using a single slide.

Publicize your research and yourself.

Compete to win a merit certificate and a gift card from ACS.

Who can participate

All presenters (Undergrad/Graduates/PhDs and Postdocs) from India who have registered for ACS Spring 2022 (In-person, hybrid, or virtual). Individual participation invites will be sent out via email with more details about the event and way to register for the event. Interested presenters can also reach out to us at acsindiasupport@acs.org.

Who can attend

All ACS Spring 2022 registrants are invited to add these events to their itinerary in the virtual meeting platform.