(644a) Hierarchically Fibrillar Biopolymer Nanostructures for Microplastics Remediation and Sustainable Polymer Substitutes

The replacement of synthetic nanomaterials with biodegradable alternatives made from abundant and sustainable biomaterials is a challenge of high societal importance. We will discuss how the process of antisolvent precipitation under shear enables the formation of diverse classes of biopolymer structuress. Specifically, we will focus on the unique capabilities enabled by a new class of soft dendritic colloids (SDCs) with hierarchically fibrillar morphology (Nature Materials, 18:1315, 2019). One emerging application of the SDCs with high societal impact is as cleaners that capture microplastics for water remediation. Traditional water treatment methods such as filtration and centrifugation are not practical for large volumes of natural water due to their high cost, low throughput, and disruption to aquatic life. We use the unique SDCs properties in “active microcleaners,” which are made of chitosan and could enable the cleanup of microplastics in various types of aquifers, including saline seawater. Finally, we report a class of high-performance multifunctional composite films made of nano- and micro-scale reinforced biopolymers: agarose matrix and chitosan SDCs. Owing to the highly entangled hierarchical network of the SDCs, the reinforced composites have excellent mechanical performance, high optical transmittance, high hydrostability, bactericidal activity and soil biodegradability. The results suggest a universal strategy for manufacturing of natural-source composite materials that could serve as substitutes for petroleum-based plastics.