Effects of Plasticizer and Microphase‐Separated Morphology on Bending Electromechanical Properties of Thermoplastic Polyurethane Elastomer/Plasticizer Blend Films

Abstract

ABSTRACT Electrobending soft actuators play a crucial role in soft robotics, medical devices, and wearable technology, enabling a variety of motions such as bending, gripping, crawling, and shaking. However, improving the electrobending properties of electroactive polymers still faces significant challenges for practical applications. This study investigates the impact of plasticizers and microphase‐separated morphologies on the bending electromechanical properties of thermoplastic polyurethane elastomers (TPU) by blending them with small quantities of different plasticizers (5 phr). The findings reveal that the microphase separation of the TPU film is significantly affected by the addition of various plasticizers, leading to the development of a morphology characterized by interconnected soft domain (SD)‐rich regions or isolated SD‐rich regions. TPU exhibiting an interconnected SD‐rich morphology demonstrated superior electrobending displacement and actuation force compared to those with a locally isolated SD‐rich structure. The TPU blended with 5 phr of ATBC achieved a bending displacement of 4.87 mm at 15 V/μm, representing a remarkable 490% increase over the TPU alone. Our results indicate that the improvement of bending electromechanical properties of TPU films can be achieved not only by adjusting their morphology but also by the incorporation of certain plasticizers.