4 - 4D-printed low-voltage electroactive polymers modeling and fabrication

Abstract

4-dimensional (4D) printing uses three-dimensional (3D) printing techniques through computer-programmed deposition of smart materials and structures in successive layers. The configuration of 4D-printed entities can vary with the external environment. Electroactive polymer materials (EAPs), a new class of smart materials, have advantages in similarity with biological muscle, easy processing, continuous deformation, and easy access to energy. Conventionally, EAPs can only be manufactured in limited 2D shapes for these traditional preparation methods involving complex processes. They are difficult to meet the needs of complex shapes actuators and sensors. Direct ink writing (DIW) is a 3D printing technology that can realize the preparation of complex 3D structures and realize integrated printing of various materials on a platform or the same structure. It is ideal for the preparation of electroactive polymer materials composed of substrate materials and conductive electrode materials. Focusing on low-voltage-driven EAPs, our laboratory mainly developed the corresponding 4D printing technology based on the DIW method. In this chapter, it will introduce the modeling and fabrication of various EAP materials, including ionic polymer-metal composite (IPMC), polyvinyl chloride gel (PVC gel), carbon nanotubes embedded in polydimethylsiloxane (CNT/PDMS), carbon nanotubes embedded in shape memory polymer (CNT/SMP), etc. In detail, the printing technologies of substrate materials and conductive electrodes will be discussed for both flexible sensors and actuators separately. Furthermore, the preliminary integrated printing of sensors and actuators will also be introduced.