Eur. Phys. J. Plus (2020) 135: 52
https://doi.org/10.1140/epjp/s13360-019-00060-9

Regular Article

Design and preparation of the composite film of SiO₂ inlaying RGO and its enhanced electro-wetting performance

Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province, College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou, 730070, People’s Republic of China

^* e-mail: wangjian@nwnu.edu.cn

Received: 6 August 2019
Accepted: 15 October 2019
Published online: 13 January 2020

Abstract

The SiO₂ composite film embedded with good conductor reduced graphene oxide (RGO) is designed based on the space charge polarization induced by the electromagnetic induction, and subsequently prepared using a simple sol–gel and spin-coating method. On one hand, the embedded RGO particles in SiO₂ coating form large amount of heterogeneous interfaces and supply amounts of free charges. When the voltage is applied, the free charges are immediately driven to be accumulated these heterogeneous interfaces by the electromagnetic induction. Then, the space charge polarization induced by the electromagnetic induction is produced and increases the dielectric constant of the film. Also, the electromagnetic induction ensures the fast response of the space charge polarization, and further decreases the relaxation time of EWOD response obviously. On the other hand, the embedment of good conductor of RGO particles also greatly decreases the effective thickness of the SiO₂ film. All these results greatly increase the capacitance of dielectric layer and further enhance EWOD performance, which are verified by the measured and calculated capacitance of the RGO@SiO₂ composite film.