Dielectric elastomers (DEs) are widely used in soft actuation and sensing. Current DE actuators require high driving electrical fields because of their low permittivity. Most of DE actuators and sensors suffer from high viscoelastic effects, leading to high mechanical loss and large shifts of signals. This study demonstrates a valuable strategy to produce polyvinyl chloride (PVC)-based elastomers with high permittivity and low viscoelasticity. The introduction of cyanoethyl cellulose (CEC) into plasticized PVC gel (PVCg) not only confers a high dielectric permittivity (18.9@1 kHz) but also significantly mitigates their viscoelastic effects with a low mechanical loss (0.04@1 Hz). The CEC/PVCg actuators demonstrate higher actuation performances over the existing DE actuators under low electrical fields and show marginal displacement shifts (7.78%) compared to VHB 4910 (136.09%). The CEC/PVCg sensors display high sensitivity, fast response, and limited signal drifts, enabling their faithful monitoring of multiple human motions.

Ionic polymer metal composite (IPMC) always takes big risks of electrode cracking and peeling, which lead to energy wasting, waterloss, and uneven electric field distribution, thus hamper its commercial applications. To address this issue, we propose a facile and effective technique to repair the electrode fatigue by coating polyvinylpyrrolidone (PVP) encapsulated Ag nanoparticles (PVP@AgNPs) on the long-term used IPMC surface. To improve the electrochemical stability, the silver nanoparticles (Ag NPs) with a diameter of ∼34 nm are encapsulated by a 1.3 nm thick PVP film, thus forming a shell-core structure to resist corrosion from the electrolyte solution. Physiochemical investigations reveal that, PVP@AgNPs closely attach to the interior and exterior surfaces of the original Pt nanograin electrode, thus refreshing its electronic conductivity; the repaired IPMC actuator exhibits better electromechanical properties compared to its precursor actuator: 7.62 folds in displacement output, 9.38 folds in force output, and 9.73 folds in stable working time.

Dielectric elastomers (DEs) have been widely used and shown great promises in soft actuation and sensing applications. However, existing DEs suffer from inherent low permittivity and high viscoelasticity, thus DE actuator requires high driving electrical field and exhibits high mechanical loss and large strain shift. Also, DE sensor exhibits low sensitivity, slow response and large signal drift. To overcome these limitations, this study demonstrates a novel and practical strategy to produce a polyvinyl chloride (PVC)-based elastomer with unprecedented properties, i.e. high permittivity and low viscoelasticity. Specifically, an introduction of cyanoethyl cellulose (CEC) into a plasticized PVC confers a high dielectric permittivity (18.9 at 1kHZ) and low viscoelastic effects with extremely low mechanical loss (tan δ = 0.05 at 1 Hz), which represent 4-fold increase in permittivity and 95% reduction in mechanical loss compared to commercial 3M VHB acrylic elastomer. Moreover, the resulted CEC/PVC DEs demonstrate superior performance in actuation and sensing as compared to the pristine PVC and other commonly used DEs. The CEC/PVC based actuator generates significantly larger strain of 12.22% and blocking force of 300 g under a low electrical field, i.e. 9.09 V/µm. The viscoelastic drift of CEV/PVC based actuator is only 3.5% over 1000 cycles, i.e. 1000 s, which is negligible when compared to 3M VHB based actuator (232.1% drift in 500 s). In addition, the CEC/PVC based sensor shows high sensitivity, stability, and fast response, which enables faithful monitoring of multiple human motions. The reported strategy can be readily applied and will be an asset to many applications, such as artificial muscle and electronic sensory skin.