An electrostrictive high dielectric constant fluorinated terpolymer sheet fabricated by a melt and stretch extrusion process

Excerpt

Lightweight and conformable electroactive polymers (EAPs) are promising for advanced electromechanical and dielectric applications such as actuators, artificial muscle systems, and high efficiency charge storage capacitors [1‐7]. EAPs are especially attractive for polymer muscle applications and demonstrate several advantages over competing approaches, exhibiting ambient operation, rapid reaction speed (microseconds to minutes), and a high mechanical energy density (~10 J/cm³) [6, 8]. Polyvinilidyneflouride-trifluoroethylene (P(VDF-TrFE)) copolymers are piezoelectric and demonstrate piezoelectric properties, but are unable to achieve high strains. It has been demonstrated that by introducing defects in P(VDF-TrFE) through irradiation or introduction of a bulky non-blocking co-monomer unit such as 1,1-chlorofluoroethlene (CFE), the resulting P(VDF-TrFE-CFE) terpolymers transition into a ferroelectric relaxor and demonstrate a large electromechanical coupling and significantly reduced electrical hysteresis while retaining high dielectric constants [2, 9‐11]. Recently, Bauer et al. [2] have found very large electrostrictive strains (7%) by these terpolymers. …