Dielectric and electret properties of novel Teflon PTFE and PTFE-like polymers

Dielectric, elastic and electret properties were investigated on pulsed-laser deposited (PLD) polytetrafluoroethylene (PTFE) on silicon substrates, on microporous PTFE foils and on hybrid electrets consisting of microporous PTFE and perfluorocyclobutene (PFCB). Dielectric dilatometry was used to detect glass- and structural phase-transitions in these nonpolar polymers: PLD-PTFE and microporous PTFE foils show the characteristic first-order phase transitions of PTFE. The fibrillar structure of the microporous PTFE results in large electrostrictive coefficients. Both the PTFE-like materials and the hybrid PTFE-PFCB electrets show excellent charge-storage stability and surpass conventional PTFE in performance. Applications can be anticipated in miniaturized electret devices as well as sensitive electret hydrophones.