Chitosan-based thermal insulation compressible foam enhanced with high performance of piezoelectric generation and sensing.

A series of chitosan (CS)-konjac glucomannan (KGM) foams with excellent thermal insulation property has been prepared using a directional freezing method, which exhibit high strain recovery, excellent piezoelectric generation and sensing properties. Layered lamellar or honeycomb morphologies in CS-KGM foams attributes a low thermal conductivity coefficient of ca. 0.03 W/(m·K). Bridge-like structure that mainly observed in CS-KGM foams from horizontal freezing endows them with excellent compression recovery performance even after 200 compression cycles. This along with piezoelectricity of CS contributes a long-lasting piezoelectric generation performance, ranging from 0.809 to 2.460 V during compression cycle process. Piezoelectric signals generated from pressing with certain strain and rate, finger taping and hand grasping can be sensed profoundly by CS-KGM. As thus, fully renewable source-based CS-KGM foams with outstanding thermal insulation and piezoelectric performance shows great potential in application as wearable thermal insulation and piezoelectric devices.