Electric antibacterial effect of piezoelectric poly(lactic acid) fabric

Abstract

Poly(lactic acid) (PLA) has a high piezoelectric constant due to molecular orientation by uniaxial elongation and crystallization by heat treatment. The piezoelectric constant of PLA yarn is approximately 10 pC•N-1. In our previous study, we reported the strong antibacterial effect of piezoelectric PLA fabrics that we had developed with fabric extension and contraction [Ando et al., Jpn. J. Appl. Phys. 56, 10PG01 (2017)]. In this study, we simulated the generating voltage of the yarn under tensile stress, considering filament slippage among adjacent filaments. Measurements were conducted to confirm the generating voltage and resulting electric field strength. Further, we confirmed that the growth of bacteria was suppressed, based on the electric field that formed in the fabric. Testing of the fabrics across multiple production lots repeatedly revealed a strong antibacterial effect, and scanning electron microscope image of dead bacteria in the fabric was different from those under the heat, drying and acid test.