Dielectric Elastomers with Liquid Metal and Polydopamine-Coated Graphene Oxide Inclusions

[Image: see text] Suspending microscale droplets of liquid metals like eutectic gallium–indium (EGaIn) in polydimethylsiloxane (PDMS) has been shown to dramatically enhance electrical permittivity without sacrificing the elasticity of the host PDMS matrix. However, increasing the dielectric constant of EGaIn–PDMS composites beyond previously reported values requires high EGaIn loading fractions (>50% by volume) that can result in substantial increases in density and loss of material integrity. In this work, we enhance permittivity without further increasing EGaIn loading by incorporating polydopamine (PDA)-coated graphene oxide (GO) and partially reduced GO. In particular, we show that the combination of EGaIn and PDA-GO within a PDMS matrix results in an elastomer composite with a high dielectric constant (∼10–57), a low dissipation factor (∼0.01), and rubber-like compliance and elasticity.