Investigation of the Mechanisms by Which Silicone Oil Affects the Properties of Electrorheological Elastomer

ABSTRACT Electrorheological elastomer (ERE) is composed of polarizable particles, an insulating matrix, and additives. Under an external electric field, the shear storage modulus of ERE can change significantly. Currently, the electrorheological effect is relatively weak, but silicone oil, as an additive, enhances this effect. This study investigates how silicone oil affects ERE performance by preparing samples with varying silicone oil volume fractions, using titanium dioxide (TiO 2 ), polydimethylsiloxane (PDMS), and dimethyl silicone oil. Results show that increasing silicone oil volume fraction enhances the electrorheological effect while reducing pressure sensitivity and affecting damping performance. Dynamic mechanical analysis revealed that at room temperature, silicone oil remains liquid in the ERE, contributing only to physical interactions. Nuclear magnetic resonance (NMR) measurements indicated that higher silicone oil content decreases the crosslink density of the elastomer matrix. This reduction facilitates greater mobility of particle chains, allowing them to tilt under normal pressure, which contributes to the observed insensitivity to pressure. Enhanced electrorheological properties of ERE enable dynamic stiffness adjustment and rapid response, ideal for aerospace, automotive, and precision machinery applications. Reduced pressure sensitivity with higher silicone oil content also offers potential for soft robotics requiring gentle handling.