Open-cell poly(vinylidene fluoride) foams with polar phase for enhanced airborne sound absorption

Abstract

Open-cell foams of polyvinylidene fluoride (PVDF) homopolymer were fabricated with the content of polar phase being changed by thermal treatment, and their airborne acoustic absorption performance properties were measured comparably in an acoustic tube. The experimental results showed that the sample with the more polar phase and hence a stronger local piezoelectric effect exhibited a significantly larger acoustic absorption coefficient. In addition to the conventional visco-inertial, thermal and materials damping effects, our analysis indicated that the thin and polar struts of PVDF foams with the polar phase and the local piezoelectric effect may further enhance the mechanical damping by converting the excited mechanical vibration to electricity through the local piezoelectric effect and increasing the friction and viscous loss at the fluid-solid interface in the presence of electrical charges. The open-cell polymer foams with high content of the polar phase and the local piezoelectric effect have great potential for passive airborne noise mitigation applications.