Keynote: A Piezoelectric Thermoplastic Elastomers Containing a Bent Core Liquid Crystal

Abstract

Piezoelectric effects in polymers are generally small but can be increased when they are compounded with ferroelectric materials. Due to their flexibility and the possibility to prepare films, polymer composites represent an advantage over ceramics and other widely used piezoelectric materials. We have created a soft, highly piezoelectric material by compression molding by which a bent-core liquid crystal was confined in a biocompatible thermoplastic elastomer, SIBSTAR. The bent-core liquid crystal in a polar smectic X-phase is characterized for having superior piezoelectricity but no mechanical stability of its own, thus requiring a carrier material. The piezoelectric response of the composite films was evaluated by interferometry experiments and the piezoelectric coupling constant was found to be d33 ~ 1 nm/V. This piezoelectric effect is larger than that of the commercially available piezoelectric ceramics, and is comparable with cellular electrets and electrospun fiber mats containing ferroelectric nanoparticles. Small Angle X-ray Scattering (SAXS) results showed that the confined liquid crystal becomes aligned in the polymer during the pressure release. The large piezoelectric effect is likely due to the vitrified macroscopic polarization created during this process. The results may pave the way for practical applications such as actuator technologies in biomedical devices.

About the Speaker

Professor Judit Puskas’ research is focusing on the integration of breast cancer diagnosis and treatment with breast reconstruction, in collaboration with the Cleveland Clinic. In 2012 was one of the five winners of the GE Healthymagination Breast Cancer Challenge Award, selected from 400 international applications. She is the winner of the 2017 Charles Goodyear Medal, the most prestigious award given by the Rubber Division of the American Chemical Society.

She joined the Department of Food, Agricultural and Biological Engineering (FABE) at the Ohio State University as a tenured Full Professor in January 1, 2019. She was named Distinguished Professor in January 2020.