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  1. null (Ed.)
  2. Abstract

    Multilayer dielectric elastomer actuators  have a wide range of potential applications, but their development and commercial implementation have been hindered by existing manufacturing processes. Existing processes are low‐throughput, limited in area, and/or can only process a narrow range of elastomers. This study presents a novel fabrication paradigm that overcomes these challenges: instead of sequentially patterning electrodes directly onto successive elastomer layers, electrode stamps are patterned onto a carrier film in an independent batch‐spray process and the electrodes are then stamp‐transferred onto each elastomer layer. By modularizing the production and assembly of electrodes, a laboratory‐scale implementation of the process achieves a throughput of 15 layers h−1, a maximum electrode size of 300×300 mm, and tuning‐free compatibility with a wide range of elastomers. The batch‐spraying paradigm also provides the unique capability to evaluate and modify electrodes before they are assembled into a multilayer; a method of mechanically treating the electrodes is employed to increase the breakdown strength of Elastosil P7670 devices from 15.7 to 33.5 V µm−1. The electrodes are conductive up to a strain of more than 200% and add negligible stiffness to the multilayer structure. The capabilities of this process to produce useful devices are demonstrated with a large‐area loudspeaker and an actuator with 60 active layers.

     
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  3. Soft robotics represents a new set of technologies aimed at operating in natural environments and near the human body. To interact with their environment, soft robots require artificial muscles to actuate movement. These artificial muscles need to be as strong, fast, and robust as their natural counterparts. Dielectric elastomer actuators (DEAs) are promising soft transducers, but typically exhibit low output forces and low energy densities when used without rigid supports. Here, we report a soft composite DEA made of strain-stiffening elastomers and carbon nanotube electrodes, which demonstrates a peak energy density of 19.8 J/kg. The result is close to the upper limit for natural muscle (0.4–40 J/kg), making these DEAs the highest-performance electrically driven soft artificial muscles demonstrated to date. To obtain high forces and displacements, we used low-density, ultrathin carbon nanotube electrodes which can sustain applied electric fields upward of 100 V/μm without suffering from dielectric breakdown. Potential applications include prosthetics, surgical robots, and wearable devices, as well as soft robots capable of locomotion and manipulation in natural or human-centric environments.

     
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  4. Abstract

    Active soft materials that change shape on demand are of interest for a myriad of applications, including soft robotics, biomedical devices, and adaptive systems. Despite recent advances, the ability to rapidly design and fabricate active matter in complex, reconfigurable layouts remains challenging. Here, the 3D printing of core‐sheath‐shell dielectric elastomer fibers (DEF) and fiber bundles with programmable actuation is reported. Complex shape morphing responses are achieved by printing individually addressable fibers within 3D architectures, including vertical coils and fiber bundles. These DEF devices exhibit resonance frequencies up to 700 Hz and lifetimes exceeding 2.6 million cycles. The multimaterial, multicore‐shell 3D printing method opens new avenues for creating active soft matter with fast programable actuation.

     
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