Strain Sensing with a Piezoelectric Biopolymer

摘要

A strain sensor was prepared using a recently developed nanocomposite material based on chitosan.Chitosan is derived from the related polymer chitin by deacetylation.Chitin is a polysaccharide,found as the major biopolymer in the exoskeletons of crustaceans such as lobsters and crabs.An advantage of chitosan is that it is soluble,enabling the preparation of samples with various geometries,in particular thin films.In addition,chitosan is biocompatible(non-toxic)and biodegradable,making its use attractive in biomedical applications.As it happens with similar biopolymers,piezoelectricity manifests itself through shear stress.A thin-film was made of chitosan reinforced with chitin nano-whiskers to add mechanical strength.The film,similar in geometry to a standard strain gage,was bonded to a cantilever beam and its terminals connected to a charge amplifier to demonstrate strain sensing.After filtering,the signal from the biopolymer sensor matches the data collected with a conventional strain gage with high fidelity.