The effect of textured surface on graphene wettability and droplet evaporation

The influence of a grain orientation and textured surfaces on the droplet evaporation and the graphene coating wettability is investigated. The study of the behavior of water droplets on graphene-coated substrates is important for the development of highly sensitive sensor technologies. The coating of the graphene layer with water leads to changes in charge concentration and electrical conductivity. To date, there are very few studies on the effect of substrate textures and wall heating on water droplets evaporation on a heated graphene coating. The contact angle depends on the ratio of several factors: textures, grain orientation and grain size. In the final stage of evaporation of a water droplet on a hot textured substrate with graphene, a jump in the contact line of the water droplet is observed. The contact angle abruptly increases almost two times. Molecular-dynamic modeling has shown that the wettability depends on the grains orientation and the annealing duration. The measured experimental value of the copper contact angle of 74–76° after annealing corresponds to the simulation results considering the direct proportionality between the contact angle and the amplitude of the first maximum of the density distributions of water molecules in the vicinity of a smooth copper surface.