Strain-Sensing Properties of Chitosan-Based Film Composites

The paper is devoted to strain-sensing properties of biopolymer composite film materials based on chitosan matrix with few-layered graphene as electrically conductive filler particles. The composite films were made by flow-coating method of colloidal dispersions of few-layered graphene in solution of chitosan in water and lactic acid with polyvinylpyrrolidone or pluronic F108 as surfactants. The experimental samples about 70–100 µm in thickness were made with few-layered graphene content of 3% and 4% (wt.) for the composites with polyvinylpyrrolidone and 2 %, 3 %, 4 % and 5% (wt.) with pluronic F108. Electrical resistivity changed from 0.016 to 1300 Ohm-m depending on surfactant and few-layered graphene content. The samples were shown to have strain-sensing properties, the strain gauge factor to be from 1.3 to 5.7 depending on the filler content and surfactant used. The strain-sensing properties were studied with beams of uniform strength (in bending), the composites bonded to them with cyanoacrylate glue. The composites are perspective as strain gauges for health monitoring due to their biocompatibility.