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The adaptive structure and excellent actuation of dielectric elastomer actuators (DEAs) make them promising candidates for soft robotics, haptic interfaces and artificial muscles. A wide variety of elastomers have been synthesised and investigated as dielectrics. Inorganic polymers such as polysiloxanes and polyphosphazenes have a low glass transition temperature. While polydimethylsiloxane (PDMS) has made its way into DEAs, the latter has received little attention in this field. Here, we present a dielectric elastomer based on polyphosphazene modified with 2,2,2,-trifluoroethoxy groups as the dielectric, which exhibits a dielectric permittivity two times higher than polydimethylsiloxanes (PDMS), excellent elasticity and a high dielectric breakdown field. These properties enable fast, reliable actuation and higher electrostatic forces than conventional PDMS. The actuators can withstand repeated actuation cycles and are suitable for long-term reliability applications. [ABSTRACT FROM AUTHOR]

Stretchable alternating current electroluminescent (ACEL) devices have a bright future in wearable electronics and soft robotics. Still, their market application is hindered by high operating voltages. The voltage can be reduced by increasing the relative permittivity of the dielectric elastomer in the emissive layer. Here, a fluorine‐free high‐permittivity silicone elastomer functionalized with cyanopropyl side groups, specially designed for application in stretchable ACEL devices, is introduced. The polar silicone elastomer exhibits excellent mechanical properties and a dielectric permittivity four times higher than commercial PDMS. Light‐emitting devices based on the polar elastomer reach 7.5 times higher maximum luminance at the same electric field than PDMS‐based devices and turn on at a 50% lower electric field. Besides, the polar elastomer‐based devices perform better than all materials tested in literature in achieving high luminance at low electric fields. Stretchable ACEL devices are built from the polar elastomer which shows bright and uniform light emission and can be operated up to 50% strain. The high‐permittivity silicones are promising materials for stretchable ACEL devices and can help their breakthrough to market application by overcoming the drawback of high operating voltages. [ABSTRACT FROM AUTHOR]

Dielectric elastomer actuators (DEAs) are a class of soft transducers with broad potential applications in soft robotics. DEAs consist of two stretchable electrodes on a dielectric elastomer, which deform and generate force when charged. The generated force is increased by placing many DEAs on top of one another to form a stack actuator. Next‐generation stack actuators require high permittivity inks that are solvent‐free processable and cross‐linkable into thin elastic films. Here, a process toward elastomers with tuneable permittivity that can be prepared solvent‐free is reported. Polycondensation of chlorosilanes yields polymers with vinyl end‐groups and cross‐linkers with multiple hydrosilane groups that both carry polar chloromethyl groups. Their dielectric permittivity and mechanical properties are tuned by changing the polar group content and the molar mass of the vinyl‐terminated polymer, respectively. Solvent‐free doctor blading provides thin films, which are cross‐linked by heating. DEAs prepared from the films reach a lateral actuation of promising 4.6% at a low electric field of 11.2 V µm‐1 and can be operated at frequencies up to 5 Hz. The high‐permittivity polymer ink is used in a solvent‐free layer‐by‐layer stack actuator fabrication, which yields an actuator with three active layers that gives a thickness strain of 1.0% at 12.4 V µm‐1. [ABSTRACT FROM AUTHOR]