Multilayer Dielectric Elastomer with Reconfigurable Electrodes for Artificial Muscle

Abstract

High‐performance multilayer dielectric elastomer actuators (DEAs) are well‐positioned to overcome the insufficient output force and energy density as artificial muscles. However, due to the fabrication process, the multilayer DEAs with nonmodifiable structures often suffer from the limitation of short lifespans and scalable preparation. Herein, reusable multilayer DEAs with the detachable and reconfigurable structure are fabricated. This is achieved by realizing scalable compliant electrodes using the continuous spatial confining forced network assembly (CSNA) method and combining the vacuum lamination (VL) approach to have good attachability and detachability with the VHB dielectric elastomer. The flexible roller‐based CSNA method is used to prepare the large area compliant electrodes composed of α, ω‐dihydroxy polydimethylsiloxane and electrically conductive nanoparticles. The fabricated electrodes can continuously work over 10 000 cycles at 40% strained stretching and maintain smooth surfaces to construct multilayer DEAs. Moreover, owing to the detachable configuration of the DEAs, the electrodes can also be recovered and reused for building new actuators. The lower limb assistive device is demonstrated by detachable multilayer spring roll DEAs, achieving approximately 3.1 degrees of flexion and extension movement of knee models under a voltage of 7 kV. The detachable and reconfigurable multilayer DEAs shed new light on the applications of wearable assistive devices.

Superstretchable Liquid-Metal Electrodes for Dielectric Elastomer Transducers and Flexible Circuits

“…The DEGs based on Supra-LMNs can charge with high efficiency despite the increased strain, which normally leads to charging losses. We compared the charging losses of DEG using Supra-LMNs electrodes, CB/polydimethylsiloxane (PDMS) rubber electrodes, and the commonly used carbon grease (CG) electrodes. ,, The resistance of Supra-LMNs on DEG at 200% strain is only 10 Ω, while the resistance of CG electrode and PDMS electrode are 69,000 and 5600 Ω, respectively. Therefore, the energy loss density ( w loss ) of Supra-LMNs electrodes during DC charging is reduced by over 99.8% compared to traditional carbon-based electrodes (see Figure f).…”

“…With a dielectric elastomer (DE) membrane sandwiched by two flexible electrodes, a dielectric elastomer transducer (DET) realizes the mutual conversion between mechanical and electrical energy and can be utilized as a dielectric elastomer generator (DEG), − dielectric elastomer actuator (DEA), − and dielectric elastomer sensor (DES). , Comparing to traditional energy converters with large volume and structural loading, the DET possesses a flexible structure, low weight, high energy-density and energy-conversion efficiency, etc . , With significant impact on power generation and driving performance of the DET, the electrodes are preferred to have a low modulus, high compliance, high conductivity, high tensile strength, and long cycle life. In addition, the development of integrated flexible circuits and portable electronic devices has increased demand for stretchable conductive materials to replace traditional rigid materials. , Till now, surpassing the trade-off between the key properties of stretchable conductive materials, i.e., compliance, conductivity, conductivity stability, and serving life remains a scientific challenge. , Recently, significant efforts are devoted to overcome these challenges. − Several “hard” conductive fillers, including carbon black (CB), carbon nanotubes (CNTs), , silver nanoparticles (AgNPs), and silver nanowires (AgNWs), have been incorporated with relatively high loading to retain their connectivity for high conductivity. However, large amounts of rigid fillers normally render the “brittleness” of such composite material and hence decreased mechanical performance of DET .…”

Purposive Design of Stretchable Composite Electrodes for Strain‐Negative, Strain‐Neutral, and Strain‐Positive Ionic Sensors

“…Since fillers in the upper layer are connected to the stable percolation network in the lower layer, the electrical performance of the double-layer composite is less susceptible to mechanical stretching. [34][35][36][37][38][39][40][41] The fillers in the upper layer are partially exposed to the air. Since the air-exposed fillers effectively contribute to the electrochemical interaction with the electrolyte, the change of the impedance spectrum under stretching is governed by the effective fraction of the air-exposed fillers.…”

Polysulfide polyurethane–urea-based dielectric composites with CeO2-loaded MXene exhibiting high self-healing efficiency

“…Polyurethane elastomer (PUE) has received scholarly attention as a dielectric elastomer owing to its relatively fast response time, 8 high electromechanical strain, 9 and ease of modification. 10 However, the poor dielectric response of PUE is one of the critical factors affecting its electromechanical conversion efficiency, restricting its application and development, especially in the field of actuators.…”