Flexible, Heat-Durable, and Highly Sensitive Piezoelectrets from Cyclic Olefin Copolymer with Microhoneycomb Structure.

This paper discusses the fabrication and characterization of cyclic olefin copolymer (COC)-based pseudo-piezoelectric materials (piezoelectrets) with exceptionally high piezoelectric activity, and their potential use in sensing applications. Piezoelectrets that utilize a novel microhoneycomb structure to achieve high piezoelectric sensitivity are carefully engineered and fabricated at a low temperature using a supercritical CO 2 -assisted assembly. The quasistatic piezoelectric coefficient d 33 of the material can reach up to 12,900 pCN -1 when charged at 8000 V. The materials also exhibit excellent thermal stability. The charge build-up in the materials and the actuation behavior of the materials are also investigated. Finally, applications of these materials in pressure sensing and mapping and in wearable sensing are demonstrated.