Enhanced electromechanical performances in plasticizer modified electrostrictive polymers

• The interface region within semi-crystalline polymer was modified by DEHP.
• The low frequency dielectric permittivity was greatly improved.
• The Young’s modulus and breakdown strength were reduced.
• The electromechanical performances were well improved.
• DEHP leads to the electrostrictive saturation occurs at low electric field.

Based on the heterogeneous nature of semi-crystalline terpolymer and the important role that interface polarization plays for dielectric and electromechanical response, small molecular plasticizer bis(2-ethylhexyl) phthalate (DEHP) was introduced into electrostrictive terpolymer to improve electromechanical performances of electrostrictive terpolymer P(VDF–TrFE–CTFE). As expected, the introduced DEHP contributes to greatly increased dielectric permittivity at low frequency, decreased Young’s modulus and moderately reduced dielectric breakdown strength of terpolymers, which are closely related with the increased mobility of polymer chains caused by DEHP. Consequently, DEHP modified terpolymers exhibit well improved electromechanical performance in contrast with pure terpolymer. The evolution of electromechanical performances of modified terpolymer with DEHP loading, electric field and frequency was well investigated for actuator applications.

By introducing plasticizer DEHP into electrostrictive P(VDF–TrFE–CTFE) terpolymer matrix, the electromechanical performances of terpolymer was well improved. For terpolymer with 10 wt.% DEHP loading, its mechanical energy density is 20 times higher than that of pure terpolymer at 30 MV/m and 0.1 Hz.Figure optionsDownload as PowerPoint slide