Piezoelectric “Kumihimo-gumi” sensor fabricated by braiding method using piezoelectric poly-L-lactic acid fiber

Abstract

We have developed a piezoelectric braided cord consisting of a conducting fiber yarn core, piezoelectric poly-l-lactic acid (PLLA) fiber yarn and a polyethylene terephthalate (PET) middle sheath, and a conducting fiber outer shield (piezoelectric PLLA braided cord). Actually, we made various types of piezoelectric PLLA braided cords using Japanese traditional braiding method called as Kumihimo-gumi in Japanese. Furthermore, by optimization based on the calculation results for each type of piezoelectric PLLA Kumihimo-gumi obtained by the finite element method (FEM), we were able to develop a new type of piezoelectric PLLA braided cord with a sensing function for complex motion (piezoelectric PLLA Kumihimo-gumi). Finally, we developed a new wearable sensor for a selfie stick which is a popular smartphone accessory, fabricated from a piezoelectric PLLA Kumihimo-gumi.