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Excellence in Graduate Polymer Research: Polymers for Electronic Applications, Conducting Polymers, Stimuli-Responsive
02:00pm - 06:00pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 14 (Marriott Marquis San Diego Marina)
Dr. H.N. Cheng, Organizer; Christine Coltrain, Organizer; Christopher Ellison, Organizer, Presider; Timothy Long, Organizer; Emily Wilts, Organizer, Presider
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person
Division/Committee: [POLY] Division of Polymer Chemistry
Tuesday
3641229 - Molecular design approach towards elastic and multifunctional polymer electronics
02:00pm - 02:25pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 14 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person
Next-generation wearable electronics require enhanced mechanical robustness and device complexity. Besides previously reported softness and stretchability, desired merits for practical use include elasticity, solvent resistance, facile patternability and high charge carrier mobility. Here, we show a molecular design concept that simultaneously achieves all these targeted properties in both polymeric semiconductors and dielectrics, without compromising electrical performance. This is enabled by covalently-embedded in-situ rubber matrix (iRUM) formation through good mixing of iRUM precursors with polymer electronic materials, and finely-controlled composite film morphology built on azide crosslinking chemistry which leverages different reactivities with C–H and C=C bonds. The high covalent crosslinking density results in both superior elasticity and solvent resistance. When applied in stretchable transistors, the iRUM-semiconductor film retained its mobility after stretching to 100% strain, and exhibited record-high mobility retention of 1 cm2 V-1 s-1 after 1000 stretching-releasing cycles at 50% strain. The cycling life was stably extended to 5000 cycles, five times longer than all reported semiconductors. Furthermore, we fabricated elastic transistors via consecutively photo-patterning of the dielectric and semiconducting layers, demonstrating the compatibility of the developed materials with solution-processed multilayer device manufacturing. The iRUM strategy is also promising for mass production when considering the cost-effectiveness and scalability of precursors as well as the reduced cost of expensive active materials resulting from the high content of iRUM precursors (~50%-75%). The highly accessible and reactive double bonds in iRUM films further provide unique opportunities for pre- and/or post-modification and interfacial engineering through chemical functionalization. This iRUM represents a molecular-level design approach for the transition from soft/stretchable to elastic and multifunctional skin-inspired electronics.

Tuesday
3648301 - Electron transport in redox-active polypeptides
02:25pm - 02:50pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 14 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person
Within a few decades, lithium-ion batteries have revolutionized technologies facilitating the development of new portable devices and electric vehicles. However, this rapid technology growth has exceeded the mining ability of lithium, cobalt and other mineral ore resources. To reduce this reliance on strategic elements, organic-based electroactive materials such as poly(TEMPO methacrylate), which has a nitroxide radical that can reversibly store energy through a reduction/oxidation mechanism, have received considerable attention. In this talk, a metal-free all-polypeptide-based battery is demonstrated, in which viologens and nitroxide radicals are incorporated as redox-active groups along polypeptide backbones to function as anode and cathode materials, respectively. The resulting battery had an initial capacity of 37.8 mAhg-1 (85% of the theoretical capacity) and a maximum cell voltage of 1.6 V. The redox-active polypeptides were stable during battery operation and could be subsequently degraded on-demand in acidic conditions. With proof of operational stability and on-demand degradation, the structure-electron transfer relationship for the viologen-based polypeptides is investigated. Three viologen-based polypeptides with varying linker spacing are studied using both experimental and computational methods. Experimentally, the heterogeneous and homogeneous electron transfer rates are evaluated with electrochemical methods including cyclic voltammetry and chronoamperometry. Computationally, the diffusion of the viologen group is determined from trajectory analysis for the three polypeptides and related to their experimentally observed charge-transport behavior. Finally, the electron transfer kinetics impact on battery performance is elucidated with half-cell batteries and varying rates of charge-discharge.
a) The diffusion cooperative electron transfer for the viologen pendant groups in a thin film. b) The three viologen-based polypeptides with varying linker spacing.

a) The diffusion cooperative electron transfer for the viologen pendant groups in a thin film. b) The three viologen-based polypeptides with varying linker spacing.


Tuesday
3649576 - Illuminating the rigid amorphous fraction of semiconducting polymers, and its pivotal influence on Optoelectronic Performance
02:50pm - 03:15pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 14 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person
Nearly all semicrystalline polymers possess two types of amorphous domains, the mobile amorphous fraction (MAF) and the rigid amorphous fraction (RAF), which exhibit distinct glass transition phenomena and govern material performance. Yet, for semiconducting polymers, there is little information about the morphological landscape surrounding these transitions at device relevant thickness and hence their identity and the role they play in device performance is obscured and of great debate. Here, we not only elucidated the identity of these transitions (backbone Tg and RAF Tg) but also the mechanism by which they control material performance in four representative semiconducting polymers (P3HT, DPPT-C8C10, N2200, and PFFBT-4T). This was first achieved through temperature dependent in-situ ellipsometry, whereby, the thermal expansion, optical profile, and conformation were all assessed. The contribution of RAF to the thermal expansion was observed to be 20% for P3HT and 75% for the remaining high-performance polymers. This was attributed to their high rigidity and paracrystalline disorder which promote crystalline-amorphous connectivity associated with RAF. The conformation and optoelectronic behavior were further assessed utilizing temperature dependent DFT simulation, GIWAXS, solid-state NMR, and OFET charge mobility, thus providing the 1st holistic picture of the influence of RAF on the performance of semiconducting polymers. Our work demonstrates that the RAF is a critical component governing polymer connectivity and subsequently optoelectronic and mechanical behavior.

Tuesday
3650352 - Impact of Interfacial Chemistry on electrochemical performance of composite magnetite electrodes
03:15pm - 03:40pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 14 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person
To meet the world’s increasingly diverse demand for energy storage, rational design of battery systems with specific performance characteristics are crucial in a wide-array of industries from automobiles to consumer electronics, among others. In this study, we used magnetite (Fe3O4) as a model active material to show how surface modification of the active material with different molecular entities of varying ionic/electronic conductivities changed the local surface chemical environment of the particles to greatly affect the electrochemical performance of the battery. We show that direct covalent attachment of poly [3-(4-carboxypropyl)thiophene] (PPBT) —a mixed ion conductor— creates a mat-like network stemming from the particle that creates anodes with enhanced lithium insertion kinetics and lithium transport processes integral in high discharge applications. These electrodes exhibit low charge transfer resistances, excellent charge capacity retention at 0.3 C, and robust charge capabilities/specific capacities. The simple attachment strategy relies on a Fischer Esterification scheme that attaches a carboxylic acid side chain of the polymer to the native hydroxide layer of the active material, thereby being applicable to the wide array of conversion-type electrodes that contain a hydroxide layer. This work contributes to the growing toolset of chemical techniques to modify active materials to create battery systems with specific performance characteristics and explores how the chemical properties of different small molecules and polymers affect the efficiency of capping agents.

Tuesday
Intermission
03:40pm - 04:10pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 14 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person

Tuesday
3656093 - Measurement of salt concentration and morphology gradients in block copolymer electrolytes using in situ Small-angle X-ray scattering
04:10pm - 04:35pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 14 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person
Solid block copolymer electrolytes with lithium salt are promising materials which could enable practical batteries with highly energy-dense lithium metal anodes. These materials phase separate into ion-conductive domains, enabling ion transport, and mechanically-rigid domains, which enhance safety. The morphology, size, and orientation of these domains can significantly impact the performance of the electrolyte, and can depend on both time and position as a gradient in salt concentration develops during application of an electric potential.

We have established a setup to obtain highly spatially- and temporally-resolved small-angle x-ray scattering (SAXS) data during in situ cycling of an electrochemical cell with lithium electrodes. We recently performed these experiments on an asymmetric polystyrene-b-poly(ethylene oxide) (SEO) electrolyte with a poly(ethylene oxide) (PEO) molecular weight of 22,400 g/mol and a polystyrene molecular weight of 4,000 g/mol, which phase separates into a majority-PEO morphology with spheres and/or cylinders—depending on salt concentration—of polystyrene. In these experiments, we have implemented equipment modifications which allow us to use x-ray transmission to directly measure salt concentration. This marks the first direct measurement of salt concentration gradients in situ in these systems, which allows us to validate theoretical predictions and better explain morphological and electrochemical behavior. Our scattering data indicates both asymmetry in domain expansion and contraction and changes between spheres and cylinders of polystyrene due to the strain of non-equilibrium changing salt concentrations; quantifying this strain allows us to gain new information about the behavior of block copolymer electrolytes in action and the mechanisms of their failure. This informs the systematic design of the next generation of solid electrolyte materials.

Tuesday
3652770 - Photo-responsive hydrogel with a coupled chemo-mechano-electro response for rewritable shape-morphing and phototunable circuitry
04:35pm - 05:00pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 14 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person
Nature creatures constantly evolving shapes and properties to realize various functions and adapt to the environment. Hydrogels as a biocompatible, highly deformable, and versatile stimuli responsiveness have the potential to mimic the adaptiveness of creatures. Traditional stimuli-responsive hydrogel usually possesses a pre-set mechano- or electro- responsiveness during fabrication. The lack of tunability and reconfigurability of those stimuli-responsive hydrogels limit their application where multifunctionality is appreciated.
In this work, a general scheme of shape and conductivity reconfigurable hydrogel with chemo-mechano-electro responsiveness using photo-ionizable molecules is proposed. Two molecules that can form a reactive ion couple upon light activation are incorporated into one hydrogel. The reaction between the ion couples not only locks the photo-ionizable molecules in the activated states but also improves the photo efficiency by drives the reversible reaction forward. Through the coordination between these two molecules, the new photo-responsive gel can decouple the photopatterning process with the morphing process meanwhile memorize the conductivity state even if the light pattern is removed. Partial conversion of the photo-ionizable molecules can be achieved by control light exposure, making it possible to continuously tunable swelling and conductivity property. Taking advantage of the reaction reversibility, the photo-responsive molecules can be recovered from the activated state with a recovery stimulus. Then the hydrogel can be rewritten into a new shape or create new conductive paths with another light pattern. Based on the proposed general scheme, a specific example is given by incorporating the triphenylmethane leucohydroxide and o-nitrobenzaldehyde molecules into a polyacrylamide hydrogel. The re-programmable morphing and the reconfigurable conductivity with precise gradient control are demonstrated.

Tuesday
Panel Discussion
05:00pm - 06:00pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 14 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person

Translational Polymer Research:
02:00pm - 06:00pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 15 (Marriott Marquis San Diego Marina)
Timothy Long, Organizer, Presider; Carmen Scholz, Organizer
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Hybrid
Division/Committee: [POLY] Division of Polymer Chemistry
Tuesday
3661007 - Science from the laboratory to the Marketplace
02:00pm - 02:30pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 15 (Marriott Marquis San Diego Marina)
Audrey Sherman, Presenter
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Hybrid
This talk will present showcase reasons to being broad based in multiple disciplines ranging from chemical synthesis and engineering processing to even art/creativity- as it relates to the industrial application of these skill sets to create new to the world ideas, concepts, and products. As a graduate of Augsburg College with a degree in both sciences and arts, I will convey real life situations where differing aspects of polymer science were used and were then combined with the communication and creativity skills from other scientific disciplines and skill sets. I plan to demonstrate how these kinds of wide-ranging fields can come together in industry and can result in real life materials and products for people to enjoy. A few examples will be the creation of a pure Silicone Diamino Precursor, as well as a product example of where this unique Raw material was deployed for the customer. Going from the Gram scale to the Ton scale. Then I will jump into a unique Chemical Crosslinking solution that has a wide application for both solvent based and 100% solids based processing.
Tuesday
3658802 - Convergent, translational research to improve human health
02:30pm - 03:00pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 15 (Marriott Marquis San Diego Marina)
Joseph DeSimone, Presenter
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Hybrid
This lecture will describe polymer-based nano- / micro-fabrication and 3D printing technologies that we have invented and employed to advance human health innovations. In 2004 we invented Particle Replication in Non-wetting Templates (PRINT), an imprint lithography-based nano- and micro-particle fabrication process affording precise and independent control over particle parameters (e.g. size, shape, composition, charge). PRINT led to the launch of Liquidia Technologies (NASDAQ: LQDA) and opened new research paths, including to elucidate the influence of specific particle parameters in biological systems, and to reveal insights to inform the design of vaccines and targeted therapeutics. In 2015, we reported the invention of Continuous Liquid Interface Production (CLIP), which overcame major limitations in polymer 3D printing—slowness, a very limited range of materials, and an inability to create parts with the mechanical and thermal properties needed for widespread, durable utility. CLIP is now transforming how products are manufactured in numerous industries. In medicine, for example, to help address shortages, CLIP enabled a new nasopharyngeal swab for COVID-19 testing to go from concept to market in just 20 days, followed by a 400-patient clinical trial at Stanford. Vast opportunities also exist to pursue next-generation medical devices and prostheses. Using CLIP, our current pursuits include software treatment planning for digital therapeutic devices in pediatric medicine, as well as single-digit micron resolution printing to advance microneedle designs as a potent vaccine delivery platform. Our impact on human health relies on our ability to enable a convergent research program to take shape that allows for new connections to be made among traditionally disparate disciplines and concepts, and to maintain a consistent focus on the translational potential of our advances.

Tuesday
3650177 - Celsion’s approach to translating its research into the market
03:00pm - 03:30pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 15 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Hybrid
Celsion is a publicly-held immuno-oncology company with technology assets in immunotherapy and vaccines. Celsion’s approach to translating its research into the market can be divided into at least three stages: demonstrate the proof-of-concept of an investigational product in an appropriate animal model, transition the product into early human clinical trials, and continuing through late-stage development leading up to a pivotal registrational study. Depending upon the product and the collaborative environment the late-stage development and FDA filing for market approval could be achieved with a partner. Since Celsion does not have sales and marketing capabilities it relies on a partner for post-approval marketing campaign and distribution.

To ensure sufficient product availability for the market Celsion’s model is to establish a reliable and redundant supply chain to fully characterize the manufacturing process and product specification during clinical development.

Due to the novelty of its therapeutic approaches and the fact that it targets diseases of unmet clinical need, Celsion anticipates sufficient outside interest in partnering in the late-stage development of its drug portfolio.

Tuesday
3653081 - Entrepreneurial polymer chemistry
03:30pm - 04:00pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 15 (Marriott Marquis San Diego Marina)
Craig Hawker, Presenter
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Hybrid
Key lessons in successfully navigating the transition from benchtop research to a commercially successful product will be illustrated through recent success stories in polymer-based pharmaceuticals and personal care products. The important of developing a broad patent portfolio, high-throughput research and the power of the internet for by-passing traditional competitive roadblocks to market penetration will be highlighted.

Tuesday
Intermission
04:00pm - 04:30pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 15 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Hybrid

Tuesday
3639076 - Simplifying ATRP toolbox for preparation of new materials
04:30pm - 05:00pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 15 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Hybrid
Atom transfer radical polymerization (ATRP) is a versatile controlled radical polymerization procedure employed to prepare block, gradient, graft, star, brush and branched functional copolymers applied as various new advanced functional nanostructured materials Some examples of commercial applications of ATRP in chemical companies will be presented.
Tuesday
3655765 - Depolymerizable polyaldehydes: Challenges in commercializing metastable materials
05:00pm - 05:30pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 15 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Hybrid
Polyaldehydes have great potential as sustainable plastics that can be chemically recycled back to their high-value monomers, a capability made possible through their favorable polymerization thermodynamics. Although this class of materials was studied in the 1960s-70s, commercial applications were not found due to their instability at room temperature and tendency to depolymerize. The means to room temperature stability has recently been found and current research has been focused on taking advantage of their ability to rapidly depolymerize. The focus of the commercialization efforts has been on semiconductor manufacturing processes and bulk plastic recycling. The commercial interest in these research efforts has led to the formation of a startup company, Polymer Solutions Inc. Polymer Solutions currently holds exclusive licenses on a family of patents and patent applications covering materials, their manufacturing, and use. This talk will discuss the science behind Polymer Solutions’ technology and discuss some of the challenges faced in advancing this technology from fundamental research through company formation, customer discovery, and exploring potential markets.

Tuesday
3655644 - Anti-adhesive bioresorbable elastomer-coated composite hernia mesh that reduce intraperitoneal adhesions
05:30pm - 06:00pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 15 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Hybrid
Intraperitoneal adhesions are a major complication arising from abdominal repair surgeries including hernia repair procedures. To prevent intraperitoneal adhesions an anti-adhesive mesh barrier should supress protein fouling and fibrosis, have mechanical properties that mimic the abdominal wall, and degrade after tissue incorporation. Herein, we report the fabrication of a composite mesh using a macroporous monofilament polypropylene mesh and a degradable elastomer coating designed to meet the requirements of this clinical application. The degradable elastomer was synthesized using an organo-base catalyzed thiol-yne addition strategy that affords independent control of degradation rate and mechanical properties. Stoichiometric control of a succinate-based dithiol incorporation into the elastomer determines the degradation timeline in vivo. The elastomeric barrier was further enhanced by the covalent tethering of antifouling zwitterionic molecules to it. Mechanical testing demonstrated the elastomer-coating on the polypropylene mesh does not exhibit micro-fractures, cracks or mechanical delamination under cyclic fatigue testing of peak abdominal loads (50 N/cm). Quartz crystal microbalance measurements showed zwitterionic functionalized elastomer exhibited reduced fibrinogen adsorption by 73% in vitro when compared to unfunctionalized control. We evaluated the composite mesh in a rabbit abdominal hernia adhesion model over 3 months, where the zwitterionic composite mesh was successful in preventing adhesions in this robust pre-clinical model. The resulting composite mesh will reduce complications related to abdominal repair through dampened fouling, reduced inflammation, and appropriate degradation rate.

Undergraduate Research in Polymer Science:
02:00pm - 06:00pm USA / Canada - Pacific - March 22, 2022 | Location: Marriott Grand Ballroom: Section 1 (Marriott Marquis San Diego Marina)
Heather Broadhead, Organizer, Presider; Sarah Morgan, Organizer, Presider; Sergei Nazarenko, Organizer, Presider
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person
Division/Committee: [POLY] Division of Polymer Chemistry
Tuesday
3659101 - Investigating the antimicrobial properties of activated carbon and the effect of polymer hydrogels through the utilization of bacterial, viral, and parasitic microorganisms OnDemand
02:00pm - 02:20pm USA / Canada - Pacific - March 22, 2022 | Location: Marriott Grand Ballroom: Section 1 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person
Activated carbon (AC) has long been utilized in biomedical applications due to its innate antimicrobial characteristics. However, little is understood about the mechanism of action that allows AC to prohibit the propagation of different pathogen species. To further ascertain these characteristics and how they affect the propagation of pathogens, procedures were designed with bacterial, viral, and parasitic agents which were utilized in conjunction with hydrogels to examine the efficacy of AC. The developed procedures analyzed AC’s ability to limit or prohibit the propagation of pathogens both with and without the presence of hydrogels through qualitative and quantitative measurements. These studies were conducted employing coconut-based AC and Polycarbophil or Carbopol 974P hydrogels which, when introduced to bacterial, viral, and parasitic agents, limited their activity. Experiments evaluated a series of bacterial dilutions with E. coli and S. aureus, bacteriophage (viral) dilutions with T1 and Φ11 bacteriophages, and Euglena Gracilis (parasite) dilutions using the AC and hydrogels listed above. Results were compared and examined through graphical analysis. When treated with AC, it was observed that all studied pathogens had a significant reduction of activity and propagation overall and that the presence of the hydrogel did not impede the antimicrobial characteristics of AC at certain concentrations. However, until the surface chemistry, porosity, and electrostatic interaction of the AC are determined, it can only be assumed that it interacts with the pathogens through adsorption.

Tuesday
3649031 - Polymer-nanoparticle hydrogels for prolonged release of GLP-1 biopharmaceuticals to improve diabetes treatment
02:20pm - 02:40pm USA / Canada - Pacific - March 22, 2022 | Location: Marriott Grand Ballroom: Section 1 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person
Globally, there are over 420 million people living with diabetes, who suffer from impaired regulation of hepatic glucose production, which eventually leads to β-cell failure. Current insulin treatments are highly burdensome, resulting in poor patient compliance, and can sometimes cause dangerous hypoglycemic events. In contrast, treatment strategies based on glucagon-like peptide-1 (GLP-1), an incretin hormone secreted from the intestinal L-cells, reduce the risk of hypoglycemia by stimulating insulin and decreasing glucagon secretion in a glucose-dependent manner. Unfortunately, current GLP-1 receptor agonists (GLP-1 RAs) must be administered either daily (Liraglutide) or weekly (Semaglutide), which results in significant patient burden and reduced patient compliance. For this purpose, we have developed a novel injectable hydrogel technology that forms through dynamic, supramolecular interactions between biodegradable nanoparticles and modified hydroxypropyl methylcellulose (HPMC) polymers. Our work aims to use this injectable depot technology as the foundation of a long-acting GLP-1 RA drug product providing 4-months of therapy per administration. Here, we exploit fatty acid moieties on Semaglutide to non-covalently embed the molecules within the hydrogel network during fabrication. We demonstrate the ability of hydrogel-based depot delivery to prolong the pharmacokinetics of Semaglutide in rat models and compare efficacy against repeated bolus dosing. We also evaluate the effect of network density, hydrophobicity of modifications to HPMC, and hydrophobic surface area of nanoparticles on cargo diffusivity and release kinetics, showing that they are highly tunable to accommodate the properties of the payload and the desired timing of its release. Overall, we anticipate this work will catalyze the development of a GLP-1 RA depot drug product for the management of diabetes by dramatically reducing the frequency of therapeutic interventions, significantly increasing patient quality of life and affording thus far unrealized therapeutic impact.

Tuesday
3654238 - Withdrawn
02:40pm - 03:00pm USA / Canada - Pacific - March 22, 2022 | Location: Marriott Grand Ballroom: Section 1 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person

Tuesday
3657755 - Synthesis of glycopolymers and evaluation of their antibacterial properties
03:00pm - 03:20pm USA / Canada - Pacific - March 22, 2022 | Location: Marriott Grand Ballroom: Section 1 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person
Antibiotic resistance is a prevailing problem in the fight against pathogenic bacterial infections. New treatment methods are needed to combat worldwide morbidity, but the search for novel antibacterial drug candidates is a persistent challenge. Glycomaterials have potential in this application since many pathogens adhere to glycans present on cell surfaces to initiate infection. Additionally, antibiotic polymers have demonstrated less susceptibility to bacterial resistance, broad-spectrum antibacterial activity, and enhanced biocompatibility when compared to traditional small-molecule antibiotics. We have synthesized a series of glycopolymers with four pendant monosaccharides (galactose, glucose, N-acetyl-glucose, and mannose) via ring-opening metathesis polymerization (ROMP) and evaluated their antibacterial activity. Minimum inhibitory concentration (MIC) assays revealed that the mannose-functionalized glycopolymers had the highest antibacterial activity against Escherichia coli, with a MIC value of 1.25 mg L-1. Additionally, higher molecular weight polymers had improved antibacterial activity, possibly due to the cluster glycoside effect. These results suggest that certain glycomaterials have inherent antibacterial properties, which might be exploited to produce novel polymer antibiotics.

Tuesday
3661301 - Quantification of a nitric oxide releasing wound healing patch
03:20pm - 03:40pm USA / Canada - Pacific - March 22, 2022 | Location: Marriott Grand Ballroom: Section 1 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person
Nitric oxide (NO) is a vasodilator and can be used to increase blood flow to an area in need of tissue repair. Through the process of electrospinning, a patch was created to release NO which is composed of four layers. The patch consists of a layer of 9% (w/w) Tecophilic®(TP)/cellulose/ascorbic acid, two layers of TP/super absorbent polymer, and a layer of TP/Dowex-NO2. Based upon previous studies, the release of nitric oxide was found to be inconsistent. In collaboration with a neighboring university, a NOx analyzer was used to effectively quantify the patch. Based on the analysis, the most effective location of release was found to be the central quadrant of the patch. The amount of NO released decreased as the sample distance from the center increased. The use of additives to the patch was explored but produced mixed results.
Set up for the electrospinning to occur in order to create the wound healing patch

Set up for the electrospinning to occur in order to create the wound healing patch


Tuesday
3655774 - Investigating the antimicrobial properties of activated carbon against bacteria, viruses, and parasites in polymeric hydrogels OnDemand
03:40pm - 04:00pm USA / Canada - Pacific - March 22, 2022 | Location: Marriott Grand Ballroom: Section 1 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person
Polyelectrolyte crosspolymers are a type of polymeric hydrogels widely utilized in personal care products. While they possess the ideal properties of suspension, shear thinning rheology and biocompatibility, they are not antimicrobial and are often susceptible to fouling. It has been demonstrated, however, that activated carbon (AC) is effective in preventing the growth and/or mobility of various pathogens. These studies explore the effect of incorporating coconut-based AC into different polymeric hydrogels on its antimicrobial mechanism of action, which would increase the longevity of personal care products. Initially, Carbopol® and Noveon Polycarbophil® hydrogels were synthesized at concentrations ranging from 0.1 to 0.5% w/v and neutralized to a pH of 4.5 or 6.5. Then, bacterial, parasitic, and viral tests were performed to compare AC’s antimicrobial capability within the hydrogels to previous studies in solution. Bacterial tests with AC against E. coli and S. aureus showed a decrease in activity in solution, however, when AC was incorporated into the hydrogels there was no observed effect. In parasitic testing, AC limited mobility of Euglena gracilis in solution, however, within the hydrogel network, no change in mobility was observed. Previous work has shown that AC inhibits viral activity, however, due to time constraints and difficulty in identifying appropriate testing methods, viral testing was not performed with hydrogels in these studies. These tests are preliminary and need to be modified in the future to determine if hydrogels are a feasible delivery system for AC.

Tuesday
Intermission
04:00pm - 05:00pm USA / Canada - Pacific - March 22, 2022 | Location: Marriott Grand Ballroom: Section 1 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person

Tuesday
Panel Discussion
05:00pm - 06:00pm USA / Canada - Pacific - March 22, 2022 | Location: Marriott Grand Ballroom: Section 1 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person

From Staudinger Macromolecules to the Genome of Macromolecules: Synthesis and Modeling Macromolecules
02:00pm - 05:35pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 16 (Marriott Marquis San Diego Marina)
Michael Klein, Organizer; Virgil Percec, Organizer, Presider; Beate Koksch, Presider
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Hybrid
Division/Committee: [POLY] Division of Polymer Chemistry
Tuesday
3678697 - Bonding through entropy
02:00pm - 02:35pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 16 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Hybrid
Many atomic and molecular crystal structures – made possible by chemical bonds – can now be realized at larger length and time scales for nanoparticles and colloids via physical bonds, including entropic bonds. The structural similarities between colloidal crystals and atomic crystals suggest that they should be describable within analogous, though different, conceptual frameworks. In particular, like the chemical bonds that hold atoms together in crystals, the statistical, emergent, entropic forces that hold hard colloidal particles together in colloidal crystals should be describable using the language of bonding. In this talk, we present a microscopic, mean-field theory of entropic bonding that permits prediction of colloidal crystals in a way that is mathematically analogous to the first principles prediction of atomic crystals by solving Schrödinger’s equation or variants thereof. We show how solutions to the theory are facilitated by the use of mathematically constructed shape orbitals analogous to atomic orbitals, using the same algorithms used in modern electronic structure codes for atomic crystal prediction.
Tuesday
3654140 - Starting from staudinger: Diversifying the macromolecular genome through carbonyl chain polymerization
02:35pm - 03:10pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 16 (Marriott Marquis San Diego Marina)
Robert B Grubbs, Presenter
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Hybrid
Poly(oxymethylene) played an important role in Staudinger's early work in polymer chemistry. Polymers like poly(oxymethylene), with acetal linkages in the backbone, have great potential as degradable or recyclable materials, and the wide variety of aldehydes and ketones that occur naturally or through sustainable transformations of naturally occurring compounds, suggests that they also have promise as sustainable materials. Glyoxylate esters are one such class of monomers that can be polymerized by treatment with bases, but monomer purification is a critical issue and the polymerization mechanism has not been studied in detail. We will discuss our efforts to control the polymerization of glyoxylate esters from hydroxyl-terminated macroinitiators and to prepare a range of block copolymers with degradable polyglyoxylate blocks, including polymers that form hydrogels. Efforts toward expanding these polymerization methods to include other monomers and investigating the sustainability of these methods will also be discussed.

Tuesday
3666187 - Programming motility of biomimetic systems via enzyme catalysis from fundamentals to applications
03:10pm - 03:45pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 16 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Hybrid
Nanoscale machines that can move autonomously, adapt their response, and deliver cargo on demand with high selectivity, represent one of the ultimate goals for researchers in the field of nano biotechnology. Inorganic and/or bio-catalytically powered, have been designed to reach that goal [1],[2] including the use of enzymatic reactions to power motion at the micro and nanoscale[3]. However, as new systems and structures are developed, there is an increasing need to understand fundamentally the aspects that affect motion output, beyond size, shape, and enzymatic reaction rate. In an effort to expand our knowledge of enzyme-powered systems, we have employed supramolecular assemblies for the dynamic encapsulation of enzymes in a stomatocyte-shaped motor, nanovesicle assembled from amphiphilic block copolymers, facilitating catalyst protection and material exchange asymmetrically. The folding process can be precisely controlled to generate different complex architectures [3] with adjustable openings and selective entrapment. The generation of gradients and motor response in such structure, does not depend only on the reaction rate, but also on the substrate and product interactions with the soft solid interface, and their effect on the particle environment. Applications of these supramolecular motors have also been explored, with a major emphasis in stimuli-responsive motion with multi-enzyme devices, with potential for on-site treatment.

Tuesday
Intermission
03:45pm - 04:15pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 16 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Hybrid

Tuesday
3678507 - Bioorthogonal chemistry for glycoprofiling and beyond
04:15pm - 04:50pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 16 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Hybrid
The molecular details of biological processes can be most accurately understood by probing biomolecules within their native habitats – in cells, or even better, live organisms. To interrogate biomolecules in such complex settings requires the means to selectively modify them with imaging probes, affinity reagents, or moieties that perturb function. Toward this end, we have focused on the development of chemical reactions that have such exquisite selectivity that they can be employed to modify biomolecules even within the environs of live organisms. Such “bioorthogonal” chemical transformations include C-C bond forming reactions with aldehydes, which we employ for site-specific protein chemical modification, as well as reactions of azides that enable in vivo imaging of metabolically labeled glycoconjugates. Progress toward the development of chemically modified protein therapeutics and methods for imaging disease-related glycans will be discussed in this presentation.

Tuesday
3652514 - Some new perspectives on old problems in materials science: Macromolecules revisited after six decades
04:50pm - 05:25pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 16 (Marriott Marquis San Diego Marina)
Michael Klein, Presenter
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Hybrid
The talk will review some of the wonderful discoveries made In the early days of research Into chain-like macromolecules. Selective solid state structures will be discussed along with attempts to model these systems using molecular simulation based on atomistic and so-called coarse grain models.
The nature of the bonding In some simple molecular crystals will be discussed and new results of Investigating their condensed phase properties using advanced density functlonal theory-based methodologies will be presented.

Tuesday
Concluding Remarks
05:25pm - 05:35pm USA / Canada - Pacific - March 22, 2022 | Location: Pacific Ballroom: Section 16 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - Hybrid

General Topics: New Synthesis and Characterization of Polymers:
02:00pm - 06:00pm USA / Canada - Pacific - March 22, 2022 | Location: Marriott Grand Ballroom: Section 11 (Marriott Marquis San Diego Marina)
Ferenc Horkay, Organizer; Yongfu Li, Organizer; Elizabeth Glogowski, Presider; Nicholas Tiwari, Presider
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person
Division/Committee: [POLY] Division of Polymer Chemistry
Tuesday
3659155 - In situ small-angle X-ray scattering studies during the formation of polymer/silica nanocomposite particles in aqueous solution OnDemand
02:00pm - 02:20pm USA / Canada - Pacific - March 22, 2022 | Location: Marriott Grand Ballroom: Section 11 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person
This study is focused on the formation of polymer/silica nanocomposite particles prepared by the surfactant-free aqueous emulsion polymerization of 2,2,2-trifluoroethyl methacrylate (TFEMA) in the presence of 19 nm glycerol-functionalized aqueous silica nanoparticles using a cationic azo initiator at 60 °C. The TFEMA polymerization kinetics are monitored using 1H NMR spectroscopy, while postmortem TEM analysis confirms that the final nanocomposite particles possess a well-defined core–shell morphology. Time-resolved small-angle X-ray scattering (SAXS) is used in conjunction with a stirrable reaction cell (see Figure) to monitor the evolution of the nanocomposite particle diameter, mean silica shell thickness, mean number of silica nanoparticles within the shell, silica aggregation efficiency and packing density during the TFEMA polymerization. Nucleation occurs after 10–15 min and the nascent particles quickly become swollen with TFEMA monomer, which leads to a relatively fast rate of polymerization. Additional surface area is created as these initial particles grow and anionic silica nanoparticles adsorb at the particle surface to maintain a relatively high surface coverage and hence ensure colloidal stability. At high TFEMA conversion, a contiguous silica shell is formed and essentially no further adsorption of silica nanoparticles occurs. A population balance model is introduced into the SAXS model to account for the gradual incorporation of the silica nanoparticles within the nanocomposite particles. The final PTFEMA/silica nanocomposite particles are obtained at 96% TFEMA conversion after 140 min, have a volume-average diameter of 216 ± 9 nm and contain approximately 274 silica nanoparticles within their outer shells; a silica aggregation efficiency of 75% can be achieved for such formulations.

Tuesday
3659162 - Molecular dynamics simulation of nafion configurations to improve O2 transport
02:20pm - 02:40pm USA / Canada - Pacific - March 22, 2022 | Location: Marriott Grand Ballroom: Section 11 (Marriott Marquis San Diego Marina)
Nicholas Tiwari, Presenter
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person
Fuel cell technology is key to the advancement of a sustainable energy economy. Polymer Electrolyte Membrane Fuel Cells (PEMFCs) are particularly promising. Its relatively high power density and low cost makes the PEMFC an ideal candidate for small applications, such as transportation, backup power units and distributed power generation. PEMFCs rely on an ion-conductive polymer to facilitate energy-producing electrochemical reactions. This ion-conductive polymer is known as an ionomer, and serves manifold purposes in the PEMFC, including oxygen transport to the surface of platinum coated catalyst particles. This research considers what structural modifications can be made to a production ionomer (Nafion) to improve oxygen transport. Findings indicate that oxygen transport is hindered by a high-density ionomer layer which forms at the surface of the catalyst particle. The formation of this layer is due to the adsorption of charged species on the ionomer to platinum particles on the catalyst surface. Structural modification of the ionomer is the most obvious way to mitigate this problem. The design space of such modified ionomers is too large to be examined through experiments, so computer simulation techniques are used. Here, it makes the most sense to use the time-dependent Molecular Dynamics (MD) technique, given that oxygen transport is time dependent.
Simulations indicate that bulky groups on the ionomer main chain, in conjunction with shorter side-chains, result in lower density at the ionomer-catalyst interface. Further simulations will clarify whether this lower density corresponds to improved oxygen transport. Should these modifications correspond to an improvement in oxygen transport, use of the modified ionomer in PEMFCs would likely result in dramatically improved reaction dynamics at the catalyst surface. This could yield more durable, higher output fuel cells.

Tuesday
3659291 - Spectroscopic signatures of MQ-Resins in silicone elastomers
02:40pm - 03:00pm USA / Canada - Pacific - March 22, 2022 | Location: Marriott Grand Ballroom: Section 11 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person
Polysiloxane elastomers have a large application space due to their versatile cross-linking chemistry and highly tunable physical and mechanical properties. One approach for improving the mechanical integrity of commercial polysiloxane ‘silicone’ elastomers while maintaining their optical transparency is the addition of small, silicone-resin molecules to the network. However, both the PDMS network and the silicone-resin particles have an amorphous structure and complex chemistry which makes the characterization of their structural properties and segmental network dynamics difficult. Here, we report the synthesis and characterization of a series of model silicone networks modified with MQ-resin using Raman and advanced nuclear magnetic resonance (NMR) spectroscopy methods. Raman spectroscopy was successfully used to quantify the contribution of the MQ-resin to the network, to determine the type of MQ-resin present in the network, and to investigate completeness of the network cross-linking reaction. Solid-state and 1H double-quantum (DQ) NMR spectroscopies were used not only as a detection method for the MQ-resins, but also to quantify changes in the segmental dynamics of the network as a function of MQ-resin concentration. The combination of Raman and NMR spectroscopies describe a series of samples where the MQ-resin particles and PDMS chains maintain their independent segmental dynamics up to high concentrations of MQ-resin (40-50% MQ), where the physical properties of the resin dominate the physical properties of the overall network. The results from our spectroscopic analyses are consistent with the results from macroscopic characterization techniques such as solvent uptake and mechanical testing. The spectroscopic insights into the structure-property relationships of PDMS-MQ composites presented in this study are a valuable tool not only for the synthesis and reverse engineering of future generations of commercial silicone elastomers, but also for understanding the mechanisms of aging and degradation over the material lifetime.
Tuesday
3659634 - Effects of self-assembled monolayer structure on conjugated polymer morphology
03:00pm - 03:20pm USA / Canada - Pacific - March 22, 2022 | Location: Marriott Grand Ballroom: Section 11 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person
Self-assembled monolayers (SAMs) are molecular assemblies that spontaneously adhere to surfaces by head groups and can be functionalized at the tail end to modify the properties of that surface. For example, SAM structures can be manipulated to alter the conductivity of the surface or lead to antimicrobial activity. In this work, we are using SAMs for surface-initiated polymerization (SIP) of conjugated polymers to form conjugated polymer brush (CPB) films. In particular, we are investigating the impact of the SAM structure on the polymer growth and resulting film morphology of CPB films of polythiophene (PT) and poly(3-hexylthiophene)
(P3HT) on silicon wafers, glass, and gold/chromium-plated surfaces. We will present our methodology for synthesis of functionalized SAMs, polymerization, and characterization of the resulting CPB films by atomic force microscopy (AFM) and water contact angle measurements.

Tuesday
3659655 - Utilizing catalyst-transfer polycondensation to prepare novel conjugated polymer structures
03:20pm - 03:40pm USA / Canada - Pacific - March 22, 2022 | Location: Marriott Grand Ballroom: Section 11 (Marriott Marquis San Diego Marina)
Pamela Lundin, Presenter
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person
Catalyst-transfer polycondensation (CTP) has emerged as an important technique for the synthesis of conjugated polymers. The chain-growth mechanism of CTP enables more control over polymer length and polymer end groups as compared to traditional step-growth methods, enabling graft-from methods for preparation of interesting conjugated polymer architectures, such as block copolymer, star polymers and surface-grafted polymers. Surface-grafted polymers are especially intriguing for organic electronic applications. To better understand the interplay between polymer and surface, we have investigated the impact of surface functionalization and polymerization parameters on the quality of polythiophene films with different alkyl substitution patterns, which we will report here. Looking forward to other potential applications for surface-grafted conjugated polymers, we will also discuss our work in studying how the electronic properties of phenylene ethynylene monomers impact their synthesis by CTP mechanisms.

Tuesday
Intermission
03:40pm - 04:00pm USA / Canada - Pacific - March 22, 2022 | Location: Marriott Grand Ballroom: Section 11 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person

Tuesday
3660874 - Extraction of sodium alginate from waste sargassum: An optimization approach using response surface methodology
04:00pm - 04:20pm USA / Canada - Pacific - March 22, 2022 | Location: Marriott Grand Ballroom: Section 11 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person
Sargassum in the Caribbean region has affected the livelihood of several coastal communities due to the influx of large quantities of this pelagic brown seaweed in recent times. Sodium alginate can be extracted from the cells walls of this seaweed but is known to give relatively low yields of borderline quality. Therefore, this study seeks to further optimize the alkali extraction process using Box- Behnken response surface design coupled with multistage extraction to obtain a higher yield and purity of alginate. Furthermore, insight into the physiochemical properties of the extracted S.natans alginate that has never been reported is found. The variables investigated were extraction temperature,
alkali concentration, and excess volume of alkali to Sargassum and extraction time. The obtained experimental data were successfully fitted to a second order polynomial equation. Optimum conditions were determined to be an extraction temperature of 80OC, 3.75 % w/v Na2CO3 , excessvolume of alkali of 12.63 mL for 6 hours and confirmed through validation experiments. Multistageextraction at the optimum conditions gave a high yield (28%) and after bleaching, high purity alginate (92%) at an extraction efficiency of 86% was obtained.

Tuesday
3660932 - Rheological properties of dually-stimuli responsive block copolymers
04:20pm - 04:40pm USA / Canada - Pacific - March 22, 2022 | Location: Marriott Grand Ballroom: Section 11 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person
Poly(2-(dimethylamino)ethyl methacrylate) or PDMAEMA dramatically switches properties, including viscosity, solubility, and interfacial tension, as a function of temperature and pH. The stimuli-responsive properties directly depend on the polymer architecture and block copolymer structure when combined with polyethylene glycol as diblock and triblock copolymers. Controlling the stimuli-responsive behavior enables tuning of the properties for applications such as architectural coatings, including paints, primers, and stains, as well as other advanced applications including for enhanced oil recovery or as rheological modifiers. Diblock and triblock copolymers were synthesized using Activators ReGenerated by Electron Transfer Atom Transfer Radical Polymerization, or ARGET ATRP, in order to control block length, molar ratio, and polymer dispersity. Block copolymers were characterized using UV-Visible spectroscopy to determine the cloud point temperature and changes to water solubility. Dynamic light scattering was used to determine if aggregation or micelle formation occured above the cloud point. The viscosity of aqueous polymer solutions and titanium dioxide dispersions were measured as a function of polymer concentration, polymer composition, and shear rate to determine the effectiveness of block copolymers to act as polymer dispersants for architectural coatings. The viscoelasticity of polymer solutions was measured as a function of polymer composition to determine the effect of frequency and temperature on the crossover point and gel point of stimuli-responsive block copolymers with controlled block structure.

Tuesday
3661424 - Water-responsive self-repairing superomniphobic surfaces via regeneration of hierarchical topography
04:40pm - 05:00pm USA / Canada - Pacific - March 22, 2022 | Location: Marriott Grand Ballroom: Section 11 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person
Superomniphobic surfaces that can self-repair physical damages are desirable for sustainable performance over time in many practical applications that include self-cleaning, corrosion resistance, and protective gears. However, fabricating such self-repairing superomniphobic surfaces has thus far been a challenge because it necessitates the regeneration of both low surface energy materials and hierarchical topography. Herein, a water-responsive self-repairing superomniphobic film is reported by utilizing crosslinked hydroxypropyl cellulose (HPC) composited with silica (SiO2) nanoparticles (HPC-SiO2) that is treated with a low surface energy perfluorosilane. The film can repair physical damage (e.g., scratch) in approximately 10 s by regenerating its hierarchical topography and low surface energy material upon application of water vapor. The repaired region shows an almost complete recovery of its inherent superomniphobic wettability and mechanical hardness. The repairing process is driven by the reversible hydrogen bond between the hydroxyl (-OH) groups which can be dissociated upon exposure to water vapor. This results in a viscous flow of the HPC-SiO2 film into the damaged region. A mathematical model comprised of viscosity and surface tension of HPC-SiO2 film can describe the experimentally measured viscous flow with reasonable accuracy. Finally, we demonstrate that the superomniphobic HPC-SiO2 film can repair physical damage by a water droplet pinned on damage or by sequential rolling water droplets.

Tuesday
3661617 - Stereoretentive olefin metathesis polymerizations to access polyalkenamers and poly(phenylene vinylene)s with high cis content
05:00pm - 05:20pm USA / Canada - Pacific - March 22, 2022 | Location: Marriott Grand Ballroom: Section 11 (Marriott Marquis San Diego Marina)
Division: [POLY] Division of Polymer Chemistry
Session Type: Oral - In-person
Due to recent advances in olefin metathesis catalyst development, research on unsaturated polymers such as polyalkenamers and poly(arylene vinylene)s has bloomed. The olefin metathesis process is usually prone to deliver alkene products in the thermodynamically stable configuration, which is the trans(E) form in most cases. As a result, polymers with high- to all-cis double bonds are relatively rare compared to their trans counterparts. Notably, the olefin configuration indeed has tremendous influence on polymers properties. For example, cis polyisoprene exhibits a more flexible texture, while the trans congener is shown to be stiffer. In addition, cis and trans poly(phenylene vinylene) also manifest significant differences in optical and physical properties.
Therefore, the development of stereoselective olefin metathesis polymerization has been considered critical to broaden the application of these polyalkenamers. Among these, stereoretentive metathesis that permits the retention of olefin configuration during the metathesis process has attracted attention for its outstanding stereoselectivity. Given that ROMP is one of the most widely-used controlled polymerizations and many monomers are inherently in the cis form, stereoretentive ROMP has been successfully exploited to obtain polyalkenamers and poly(arylene vinylene)s with high- to all-cis structures. In addition to ROMP, stereorententive acyclic diene metathesis (ADMET) polymerization was developed to take advantage of the streamlined synthesis of diene monomers. This protocol delivered a variety of high- to all-cis polyalkenamers, demonstrating high functional group tolerance. We anticipate these stereoselective olefin metathesis polymerizations to enrich the applications of polyalkenamers with tunable properties based on the cis to trans ratio.