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Electrostriction facilitates the electric field-stimulated mechanical actuation of dielectric materials. This work demonstrates that introduction of dielectric mismatched nanodomains to a dielectric elastomer results in an unexpected ultralarge electrostriction coefficient, enabling a large electromechanical strain response at a low electric field. This strong electrostrictive effect is attributed to the development of an inhomogeneous electric field across the film thickness due to the high density of interfaces between dielectric mismatched periodic nanoscale domains. The periodic nanostructure of the nanostructured gel also makes it possible to measure the true electromechanical strain from the dimensional change monitored via in situ synchrotron small angle X-ray scattering. The work offers a promising pathway to design novel high performance dielectric elastomers as well as to understand the underlying operational mechanism of nanostructured multiphase electrostrictive systems.

Silicone elastomer actuators were investigated to develop a simple and industrially scalable product with improvedmechanical properties, such as a low modulus, high tearing strength, and goodresilience, and enhanced electromechanicalactuation properties. Silicone elastomers were fabricated via a hydrosilylation addition reaction with a vinyl-end-functionalizedpoly(dimethyl siloxane) (V), a multivinyl-functionalized silicone resin, and a crosslinker in the presence of a platinum catalyst.For the larger electromechanical actuation response, the silicone dielectric elastomer actuator had to have a larger molecularweight of poly(dimethyl siloxane), a smaller hardener content, and a resin-free composition. However, the silicone elastomeractuators needed to include a small amount of resin to improve the tearing strength. V C 2013 Wiley Periodicals, Inc. J. Appl. Polym.Sci. 2014, 131, 40030. KEYWORDS: crosslinking; dielectric properties; elastomers; sensors and actuatorsReceived 31 May 2013; accepted 2 October 2013DOI: 10.1002/app.40030INTRODUCTION

In this paper, we demonstrate an easy way to prepare a stable reduced graphene oxide (RGO) dispersion in aqueous or organic media by simple adjustment of the degree of reduction and pH of RGO dispersion, and a subsequent fabrication of transparent conductive RGO thin films on various substrates using a spray coating technique. RGOs were prepared using a hydrazine reducing agent from graphene oxide (GO), which was oxidized from graphite via a modified Hummers’ method. The degree of reduction determined the surface properties, such as atomic composition, surface polarity, and potential of RGO platelets. In addition, pH significantly affected the surface potential of graphene dispersion. The fine adjustment of degree of reduction and pH of RGO dispersion made production of fine RGO dispersions in aqueous and organic media such as ethanol and DMF possible without any aid of dispersing agents. The stable RGO dispersion using volatile ethanol medium provided a unique advantage to be spray-coated into uniform transparent conductive RGO thin films on various substrates including silicon wafer, flexible polycarbonate film regardless of their surface properties, and even on non-planar substrates such as round-shaped glassware at room temperature.