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

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.

Keywords:

• graphene oxide (GO)-encapsulated silica (SiO2) hybrids
• electrostatic self-assembly
• polydimethylsiloxane (PDMS) elastomer
• dielectric constant (k) and mechanical properties
• actuated strain at low electric field

Additional information

Funding

We would like to express our sincere thanks to the National Natural Science Foundation of China [grant number 51173007], [grant number 51103090], [grant number 51221002] for financial support.