Soft robotics revolutionized human-robot interactions, yet there exist persistent challenges for developing high-performance soft actuators that are powerful, rapid, controllable, safe, and portable. Here, we introduce a class of self-contained soft electrofluidic actuators (SEFAs), which can directly convert electrical energy into the mechanical energy of the actuators through electrically responsive fluids that drive the outside elastomer deformation. The use of special dielectric liquid enhances fluid flow capabilities, improving the actuation performance of the SEFAs. SEFAs are easily manufactured by using widely available materials and common fabrication techniques, and display excellent comprehensive performances in portability, controllability, rapid response, versatility, safety, and actuation. An artificial muscle stretching a joint and a soft bionic ray swimming in a tank demonstrate their effective performance. Hence, SEFAs offer a platform for developing soft actuators with potential applications in wearable assistant devices and soft robots.
Hang Yang,Junfeng Wang,Dongbao Wang,Daorui Wang,Jian Gao,Bin Li
The regulation of particle-laden droplet behavior is crucial for interfacial heat and mass transfer in the liquid-liquid reaction systems. Accordingly, a clear understanding of droplet dynamic behaviors is of crucial importance. In this study, the behaviors of solid-particle-laden droplets in an immiscible dielectric liquid are experimentally investigated under the effect of a non-uniform AC electric field by high-speed imaging. The evolution processes of droplet formation, coalescence, dispersion as well as liquid bridge are analyzed systematically in variable applied voltages and particle concentrations. Results show that the droplet formation process are accelerated by increasing particle concentration, producing smaller droplets. When the applied voltage exceeds a certain threshold, the charged droplet coalescence occurs while the presence of particles would reduce this critical voltage. Cascade coalescence happens in the pure system with increasing voltage while the particle-laden droplets tend to coalesce individually. The droplet dispersion is found to dominate at high electric field strengths with its oscillation angle increased by particle concentration. Additionally, the liquid bridge expansion is reduced by the addition of particles, hindering the droplet coalescence. These findings provide insights into the regulation of particle-laden droplet behavior under the effect of electric fields.
Yingying Shu,Chaofan Wang,Zhengyong Huang,Changheng Li,Feipeng Wang,Jian Li
Natural ester dielectric fluids are eco-friendly alternatives to petroleum-based dielectrics, but oxidative instability from unsaturated bonds limits operational lifespan in transformers. While carnosic acid (CA) enhances soybean oil (SO) oxidation resistance, it introduces unacceptable dielectric loss and acidity. This challenge was addressed through the development of methyl carnosate (MC), a CA derivative that reduces acidity and dielectric loss while retaining the antioxidant catechol moiety. Thermal analysis and electron paramagnetic resonance (EPR) spectroscopy show MC significantly improves SO oxidation stability without compromising dielectric properties. MC-doped SO exhibits > 10 °C higher oxidation onset temperature and delayed thermo-oxidative decomposition due to potent radical scavenging. Conformational analysis and bond dissociation enthalpy calculations reveal that MC’s dominant conformation, stabilized by intramolecular hydrogen bonding, facilitates preferential H-donation from the hydroxyl group ortho to the aliphatic ring, confirming sacrificial antioxidant behavior. MC is a promising eco-friendly antioxidant for natural ester dielectrics, enhancing longevity and performance
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