In this work, alternating poly(butyl vinyl ether-co-acrylonitrile) (P(BVE-co-AN)) copolymer was found to exhibit temperature-dependent strain recovery when it was heated through its glass-transition temperature (Tg ~ 26 °C). This copolymer is amorphous and contains polar side groups in its structure, thereby exhibiting a switch in permittivity when passing through the glass transition. The strain-recovery effect accompanied by the change in permittivity and thickness occurring around room temperature can be exploited in electro-active applications such as thermal capacitive sensors and energy harvesting

A novel piezo- and pyro-electric elastomer electret was prepared using polar amorphous polynorbornene (PNBE) as the electroactive filler in a polydimethylsiloxane (PDMS) matrix. Under the influence of an electric field, the composite was heated above the glass transition of the filler and subsequently cooled back to room temperature (RT), thereby freezing the oriented dipoles. The resultant composites with 30 wt.% of PNBE showed a high piezoelectric d31 coefficient of 37 pC/N and a quasi-static pyroelectric coefficient of 0.54 μC/m2K.