Wetting properties of graphene and multilayer graphene deposited on copper: The influence of copper topography

Abstract

Graphene-based coatings are promising in optoelectronic, membrane, sensor-related and cooling technologies due to their outstanding properties. However, during the use of these applications, coatings are contacting with water. Therefore, changes in the wetting properties and water evaporation rate on graphene-coated samples are of particular interest to ensure the correct operation of these devices. The purpose of this work is to study the influence of texture, crystallographic orientation and annealing on wetting and water droplet evaporation on copper with graphene or multilayer graphene coating. The texture and grain structure of graphene coated copper samples were analyzed using Raman scattering and scanning electron microscopy. Modifying the surface texture by pressing and varying the annealing time makes it possible to achieve the orientation of grains (111), as well as the simultaneous presence of different crystalline orientations. Wetting properties were changed in a fairly wide range of water contact angles (72°–110°) by changing the annealing time, texturing the surface and forming the graphene-based coating and MLG coating. The droplet evaporation modes, evaporation time and evaporation rates varied on different surfaces. A texture surface accelerated the droplet evaporation; a smooth copper surface maximized the evaporation time while surface texturing from multilayer graphene coating minimized it.