Electrostrictive thermoplastic polyurethane-based nanocomposites filled with carboxyl-functionalized multi-walled carbon nanotubes (MWCNT-COOH): Properties and improvement of electromechanical activity

The thickness strain SZ and apparent electrostrictive coefficient M were measured at low electric fields, E ⩽ 4 V/μm, by low frequency of 0.1 Hz. The maximum induced-compressive strain was obtained from an optimal volume fraction of 0.8 v% which yielded to a high Sz = 11.5%, corresponding to almost a threefold increase of M compared to the neat TPU. Beyond fc, the conductivity sharply raised up and thus the electrostrictive activity disappeared.