Supramolecular covalent cellulose-based bioplastics with high transparency, hydrophobicity, ionic conductivity, mechanical robustness, and recyclability

Driven by environmental protection and sustainable development, the exploitation of cellulose-based bioplastics (CBPs) with high transparency, hydrophobicity, mechanical toughness, heat sealability, ionic conductivity, and recyclability is highly desirable. However, it is very challenging to concentrate multiple functionalities into one material. Herein, a series of supramolecular covalent CBPs was innovatively synthesized by simple solvent treatment and rapid photopolymerization based on the compatibility of ethylcellulose with a polymerizable hydrophobic deep eutectic solvent. By regulating the ratio of components, the obtained CBPs exhibited good overall performance, including optical transmittance (similar to 92%), water resistance, mechanical toughness, heat-sealing performance, and shape-memory function. Moreover, a wet strength of up to similar to 10 MPa could still be maintained after long underwater immersion for 24 h. The introduction of lithium salts endowed the obtained CBPs with ionic conductivity, enabling it to exhibit excellent pressure and deformation sensing capabilities both in air and underwater. Moreover, the CBPs could be simply and rapidly recycled by solvents, and the performance did not degrade significantly after recycling many times. The CBPs prepared in this study have promising applications in the field of green flexible electronics and smart packaging in the future. A novel CBP with good optical transmittance, hydrophobicity, mechanical toughness, heat sealability, ionic conductivity, and recyclability is reported.