Charge storage and mechanical properties of porous PTFE and composite PTFE/COC electrets

Abstract

Recent futuristic applications of flexible electret loudspeakers have garnered much interest for these novel loudspeakers. To increase the loudspeaker properties, a processing method was developed to improve the electret and mechanical properties of porous PTFE film. Taking a thin porous PTFE film as the base material, a cyclic olefin copolymer (COC) was coated to a base material to form a PTFE/COC composite film. Results show that the composite material improves the advantageous characteristics when used as an electret diaphragm for loudspeakers. By measuring the surface potential decay and the elastic modulus, properties of a standard porous PTFE film were compared to an improved composite PTFE/COC film. Experimental results showed that the composite PTFE/COC possess the following advantages: (1) 80% higher surface potential after 10 days at room temperature, (2) a better thermal resistance of charge storage, and (3) a 643% higher elastic modulus. Therefore, our novel composite material can be used to create a much improved electret diaphragm for flexible electret loudspeakers.

Ultrafine, self-crimp, and electret nano-wool for low-resistance and high-efficiency protective filter media against PM0.3

“…The intrinsically different electronic transport capabilities between PVDF and HAP resulted in a charge barrier, which is hard to overcome. As a result, charges tend to accumulate at the interfacial zones instead of being transferred from one to another, leading to the formation of interfacial charges [36] , [37] . It is worth noting that we propose that the classical Maxwell-Wagner effect can serve as an essential electret mechanism for ESNs, which might be identified as a progress since it has been employed to analyze the interfacial charges of buck bi-layer materials conventionally.…”