Electrically Triggered Actuation of Plasticized Thermoplastic Polyurethane Gels

Abstract

Thermoplastic polyurethanes (TPUs) are copolymers with hard and soft segments. They have excellent physical properties and good biocompatibility. In particular, their shape memory properties and compatibility with plasticizers make TPU gels suitable for use as soft actuator materials. In this work, a plasticizer, dibutyl adipate (DBA), is added to four types of TPU to form gels. All the TPUs form transparent soft gels with different DBA contents. Their dielectric and mechanical properties are significantly improved by DBA addition, and the TPUs are changed from insulators to electrical actuation materials. Polyether TPU/DBA gels show the most significant changes. The bending distance of a TPU/6DBA gel tip (dimensions 20 × 5 × 0.3 mm3) is about 15 mm when the gel is sandwiched between soft electrodes and an electric field of less than 3 V μm–1 is applied. The developed materials show large deformations at low energies, and will make a significant contribution to the field of actuation materials. It is believed that TPU/DBA gels can be used as photovoltaic, dielectric, artificial muscle, robotic, and other smart materials. image