A Fully Biobased Encapsulant Constructed of Soy Protein and Cellulose Nanocrystals for Flexible Electromechanical Sensing

Presently, flexible electromechanical sensors are of particular interest to next generation mobile applications. To enrich the flexible encapsulants, herein, a fully biobased film is developed by cross-linking soy protein isolate (SPI) with nanocross-linker, aldehyde-bearing, cellulose nanocrystals (CNC). Thanks to the enhanced interfacial interaction between SPI and CNC resulting from the Maillard reaction, the protein-rich phase becomes more homogeneous with smaller domain size. Compared with neat SPI film, the resultant composite films exhibit an obviously improved mechanical property and water resistance. In particular, the heat-sealing property of such films is well maintained, which guarantees their application as encapsulation layers to construct flexible electromechanical sensors. These results indicate that green composite films hold promising applications as universal encapsulation materials for integrating flexible movement-monitoring electronics.