A Highly Sustainable Supramolecular Bioplastic Film with Superior Hydroplasticity and Biodegradability

Abstract Massive accumulation of postconsumer plastic waste in eco‐system has raised growing environmental concerns. Sustainable end‐of‐life managements of the indispensable plastic are highly demanding and challenging in modern society. To relieve the plastic menace, herein we present a full life cycle sustainable supramolecular bioplastic made from biomass‐derived polyelectrolyte (chitosan quaternary ammonium salt, QCS) and natural sodium fatty acid (sodium laurate, SL) through solid‐phase molecular self‐assembly (SPMSA), by which the QCS‐SL complexes, precipitated from mixing the aqueous solutions, self‐assemble to form bioplastic film by mildly pressing at room temperature. The QCS‐SL bioplastic films display superior hydroplasticity owing to the water‐activated molecular rearrangement and electrostatic bond reconstruction, which allows facile self‐healing and reprocessing at room temperature to significantly extend the service lifetime of both products and raw materials. With higher water content, the dynamic electrostatic interactions and precipitation‐dissolution equilibrium endow the QCS‐SL bioplastic films with considerable solubility in water, which is promising to mitigate the plastic accumulation in aquatic environment. Because both QCS and SL are biocompatible and biodegradable, the dissolved QCS‐SL films are nontoxic and environmentally friendly. Thus, this novel supramolecular bioplastic is highly sustainable throughout the whole life cycle, which is expected to open a new vista in sustainable plastic materials.