Nature abounds with fascinating structures that inspire synthetic replication, many of which derive remarkable properties from assembled mesoscale building blocks. Of particular interest are mesoscale fibrils that have the ability to align and bundle in load-bearing macrostructures, or work in concert with dissimilar architectures including cells and droplets, to make spider silk that remains taut when contracted or flagella that enable cellular movement. Despite such compelling natural materials, few examples of well-defined synthetic mesostructures exist, particularly with the ability to access diverse behaviors and properties from the same fundamental building blocks. This work outlines the development of “mesoscale polymers” (MSPs) as a class of materials with access to diverse chemical functionality and the ability to realize sophisticated assemblies. Our method spans synthesis and characterization of monomers and polymers, printing of ribbon-like MSP mesostructures, and MSP release from the substrate surface to interact with a high-energy oil-water interface. In this work, we choose a pH-responsive copolymer featuring pendent tertiary amines, and a patternable copolymer acting as a single-component resist to illustrate the facile use of numerous materials. Embedded within the MSP platform, these two polymers work in concert with the structure’s high bending compliance and programmable interfacial activity to afford dramatically different structures, including spider silk-like spools and droplets with pendent arms, from the same fundamental MSP and droplet constituents. Moreover, we achieve a quantitative understanding by measuring the work of adhesion, G_c, and a critical elasto-adhesive dimension, R_c, governing MSP-droplet interactions. These measurements and diverse assemblies underpin the utility of the MSP platform as an adaptable tool for the preparation of bioinspired mesostructures.

Alfred J Crosby

Professor, University of Massachusetts Amherst

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