Low Voltage and Low Temperature Soft Electrothermal Actuator Based on PE/Graphite Bilayer Film

Abstract

Soft electrothermal actuators are widely used in soft robots, smart switches, medical devices, artificial muscles, and human-machine interactions. Generally, they operate at room temperature but also meet the safety standards for maximum safe voltage for a human body. Therefore, an actuator with a lower voltage and lower temperature is the first choice, as long as the performance is not affected. In this study, a bilayer film based on polythene (PE)/graphite is used to realize an electrothermal drive. The method is simple, inexpensive, and convenient for mass production. At a low driving voltage of between 1.5 and 2 V, and at a temperature of 40-52 °C, a maximum bending angle of 139.22°-470°. Through the demonstration of a micromechanical gripper and transportation illustrated by drug crawling, it is proven that the PE/graphite composite membrane can be widely applied in the field of soft actuators.

Recent Advances in Electrically Driven Soft Actuators across Dimensional Scales from 2D to 3D

“…For this bilayer actuator, the difference in expansion between two layers could induce a bending deformation. Based on this deformation mechanism, an electrical electrode as a heater can be integrated in the actuator [55,56] or one deformation layer with better conductivity can also act as the heater [57,58] to create the thermal expansion-based soft actuators. [59][60][61][62][63] The heating electrodes of the soft actuators also need to be flexible with very low deformation stress, for the purpose of producing a minimum degree of stress resistance to the deformation of the actuator.…”

“…For this bilayer actuator, the difference in expansion between two layers could induce a bending deformation. Based on this deformation mechanism, an electrical electrode as a heater can be integrated in the actuator [ 55,56 ] or one deformation layer with better conductivity can also act as the heater [ 57,58 ] to create the thermal expansion‐based soft actuators. [ 59–63 ]…”

Fully Handwritten Flexible Electrothermal Devices Using a Whiteboard Marker Pen with Carbon Nanoparticle Ink

“…In addition, the low bending stiffness and high specific surface area of carbon nanomaterials guarantee enough mechanical strength for fabricated devices, restraining the growing fracture during use. 34 Xu et al 12 prepared ETAs based on polythene (PE) and graphite with a low driving voltage range of 1.5−2 V and with low driving temperatures between 40 and 52 °C. Chang et al 35 designed graphene-based bimorph actuators with dual-response and large deformation under 7 V. Quinsaat et al 36 filled carbon conductive inks containing graphene and carbon black into poly(dimethylsiloxane) (PDMS) and processed into thin membranes by screen printing to serve as electrode for DEAs, which may prove the feasibility to fabricate ETAs with conductive carbon ink by screen printing.…”

“…On the other hand, ETA is a kind of soft actuator that can produce various movements from thermal expansion induced by Joule heating. − Considering the practical applications, researchers have attached more importance to electrothermal actuators (ETAs) because of the potential to solve tough problems such as limited working conditions. , Specifically, the ETAs are distinct from electroactive polymer (EAP) actuators including dielectric elastomer actuators (DEAs), electroactive hydrogel (EAH) actuators, , and ionic polymer–metal composites (IPMCs), which demand either high driving voltage or special conditions such as electrolytes.…”

Research Progress on the Preparation of Flexible and Green Cellulose-Based Electrothermal Composites for Joule Heating Applications

“…When a voltage is applied to ETCs, the internal conductive fillers act as heaters to convert electrical energy into heat via the Joule heating effect. Commonly used conductive fillers include carbon nanotubes (CNTs), graphene (GP), silver nanowires (AgNWs), 2D transition metal carbides and/or nitrides (MXenes), and conductive polymers; the polymer matrix consists of thermosetting resins, thermoplastic resins, cellulose, and rubber . ETCs have recently attracted much research attention owing to their low weight, controllable temperature, uniform heating, high electric-to-radiant power transfer efficiency, and simple production process.…”