GUO Yufeng, GUO Wanlin. Effects of graphene coating and charge injection on water adsorption of solid surfaces. Nanoscale, 2013,5, 10414-10419.

Effects of graphene coating and charge injection on water adsorption of solid surfaces
Yufeng Guo*a and Wanlin Guo*a

a.State Key Laboratory of Mechanics and Control of Mechanical Structures and MOE Key Laboratory for Intelligent Nano Materials and Devices, Institute of Nanoscience, Nanjing University of Aeronautics and Astronautics, Nanjing, China
E-mail: yfguo@nuaa.edu.cn, wlguo@nuaa.edu.cn;
Fax: +86 25 84895827 ;
Tel: +86 25 84890513

Nanoscale, 2013,5, 10414-10419
DOI: 10.1039/C3NR02867D
Received 03 Jun 2013, Accepted 17 Aug 2013
First published online 27 Aug 2013

Abstract

The adhesion and cohesion of water molecules on graphene-coated and bare copper and mica substrates under charge injection have been extensively studied by first-principles calculations. Water adsorption on graphene-coated copper surface is weakened by injecting negative charges into the substrate, while enhanced by positive charges. Both negatively and positively charge injecting on graphene-coated mica strengthen the adsorption between water and the surface. While the adhesive and cohesive energies of water adsorption on charged bare copper and mica exhibit similar trends and much stronger response to charge injection. The charge sensitivity of water adsorbing on positively charged surfaces is significantly weakened by the graphene coating layer, mainly due to lower interfacial charge exchange. Our results suggest a viable way to modify water adsorption on a graphene-coated surface and unveil the role of graphene as a passivation layer for the wetting of a charged substrate.

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