Soft electrothermal actuator array for surface morphing application

Electrothermal actuators (ETAs) have been the focus of continuous R&D in targeting soft actuator applications. This article explores both the fabrication and design characteristics of a poly(dimethylsiloxane) (PDMS) elastomer—carbon nanotube buckypaper layered composite in the dual cantilever bending arrangement. Actuation characterization tests demonstrate the relationship between actuator geometries, boundary conditions, and heating rate to the maximum bending deflection. SEM observations on the cross sections of the ETAs fabricated with different conductive layers display the variations in thickness, and the effects of localized heating zones are discussed. By comparing different fabrication methods, improvements to the actuation features through ETA design modification were reported, and the possibility to greatly increase the actuation was displayed. The potential of ETAs as surface morphing actuators is demonstrated in concept through fabrication of a single sheet array consisting of multiple ETAs with the ETA segments individually and simultaneously activating to create hill-like features. Impact statement Exploring the fabrication of novel soft robotic actuators shows great promise in creating devices that are lightweight, flexible, and multifunctional. These actuators can provide a unique alternative to conventional mechanical solutions. For example, as lightweight and low-profile surface actuators where conventional mechanical actuators are too bulky. This article discusses an investigation of the bending deformation of various designs of electrothermal actuators and the various factors that influence the actuation performance such as geometry, electrical conductivity, and actuator fabrication methods. To better understand the behavior, several characterization tests and various fabrication methods are demonstrated. The aim is to investigate and understand the fundamental factors that influence the deformation of electrothermal actuators and develop a shape conformable array of actuators for shape-morphing applications. The overall performance of the developed actuators shows great promise for improving soft robotics systems. Graphical abstract