Flexible actuators

Abstract

Flexible actuators exhibit large deformation under external stimulus with advantages of lightweight, softness, and arbitrary shape. Although the technology of flexible actuator used in smart textiles is still at embryonic stage, its shape change and force generation can bring some new fancy functions to smart textiles and advance their intelligence. Flexible actuator is a wide-ranging concept that refers to flexiblematerial (most are based on polymers) that is capable of imparting a force and/or motion. They are divided into three categories, dielectric electroactive polymers (EAP), ionic electroactive polymers, and other flexible actuators. For each category, some typical actuators are introduced including their actuation mechanisms, actuation properties, and possible process integrated into a textile. Dielectric elastomer and PVDF-based actuators exhibit large strain, high output force, and wide operation frequency but need a relative high driven voltage. Ionic polymer-metal composites (IPMCs) and bucky-gel actuator show large bending deformation under a low voltage but small blocking force and low operation frequency. Thermal-driven actuator and shape-memory polymer often need a heat stimulus. All of them help us to explore their possible applications in smart textiles. Currently, there is rare specific application of flexible actuator technology in smart textiles. However, enormous applications can be envisioned when combining flexible actuators and smart textile. Flexible actuators can produce dynamic shape, generate force or bending moment, and release substance as actuators. They can be used for smart fashion design, assisting people and healthcare in daily life and human-machine interface. In this chapter, some interesting clothing designs are proposed including dynamic decorations, body contouring suit, rehabilitation suit, acupoint massage suit, astronaut suit, drug delivery patch, and force/haptic feedback suit. The field of smart textile is sure to be affected significantly by the application of the flexible actuator technology in the future.