Simultaneously improved actuated performance and mechanical strength of silicone elastomer by reduced graphene oxide encapsulated silicon dioxide

Nanying Ning,Liqun Zhang,Minglu Wang,Ming Tian,Jing Zhang

doi:10.1080/19475411.2015.1130757

Abstract

Herein, graphene oxide (GO)-encapsulated silica (SiO2) hybrids (GO@SiO2) were prepared via electrostatic self-assembly of the 3-aminopropyltriethoxysilane (APS)-modified SiO2 and GO. The as-prepared GO@SiO2 was introduced into polydimethylsiloxane (PDMS) elastomer to simultaneously increase the dielectric constant (k) and mechanical properties of PDMS. Then, the in situ thermal reduction of GO@SiO2/PDMS composites was conducted at 180°C for 2 h to increase the interfacial polarizability of GO@SiO2. As a result, the values of k at 1000 Hz are largely improved from 3.2 for PDMS to 13.3 for the reduced GO@SiO2 (RGO@SiO2)/PDMS elastomer. Meanwhile, the dielectric loss of the composites remains low (<0.2 at 1000 Hz). More importantly, the actuated strain at low electric field (5 kV/mm) obviously increases from 0.3% for pure PDMS to 2.59% for the composites with 60 phr of RGO@SiO2, an eightfold increase in the actuated strain. In addition, both the tensile strength and elastic modulus are obviously improved by adding 60 phr of RGO@SiO2, indicating a good reinforcing effect of RGO@SiO2 on PDMS. Our goal is to develop a simple and effective way to improve the actuated performance and mechanical strength of the PDMS dielectric elastomer for its wider application.

Highlights

Dielectric elastomers (DEs), as an attractive branch of electro-active polymers (EAPs), can give rise to surprisingly large deformation when stimulated by an electric field, and work efficiently over a broad frequency range
graphene oxide nanosheets (GONSs) are negatively charged in aqueous solution because of the ionization of the carboxylic acid groups and phenolic hydroxy groups on their surface
We developed a simple and efficient method to simultaneously improve the actuated performance and mechanical strength of a silicone elastomer

Summary

Introduction

Dielectric elastomers (DEs), as an attractive branch of electro-active polymers (EAPs), can give rise to surprisingly large deformation when stimulated by an electric field, and work efficiently over a broad frequency range. They have received much attention in the past two decades [1,2]. A dielectric elastomer actuator (DEA) can shrink in the thickness direction and expand in the plane direction by applying an electric field across the film thickness [3]. Getting a large actuated strain at a low electric field is the biggest challenge for DEAs

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Conclusion