title: A nonmonotonic dependence of the contact angles on the surface polarity for a model solid surface.
abstract: Based on molecular dynamics simulations, we found a nonmonotonic relationship between the contact angle of water droplets and the surface polarity on a solid surface with specific hexagonal charge patterns at room temperature. The contact angle firstly decreases and then increases as polarity (denoted as charge q) increases from 0 e to 1.0 e with a vertex value of q = 0.5 e. We observed a different wetting behavior for a water droplet on a conventional nonwetted solid surface when q ≤ 0.5 e, and a water droplet on an ordered water monolayer adsorbed on a highly polar solid surface when q > 0.5 e. The solid-water interaction, density of water, hydrogen bonds, and water structures were analyzed. Remarkably, there was up to six times difference in the solid-water interactions despite the same value of the apparent contact angle values.
authors.affiliation: School of Physics, Shandong University, Jinan 250100, China. yzheng@sdu.edu.cn and Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, P. R. China. wangchunlei@sinap.ac.cn.
authors.forename: Chonghai
authors.initials: C
authors.lastname: Qi
authors.affiliation: School of Electronic Engineering, Chengdu Technological University, Chengdu 611730, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhou
authors.affiliation: Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, P. R. China. wangchunlei@sinap.ac.cn.
authors.forename: Chunlei
authors.identifier: http://orcid.org/0000-0002-4353-9140
authors.initials: C
authors.lastname: Wang
authors.affiliation: School of Physics, Shandong University, Jinan 250100, China. yzheng@sdu.edu.cn.
authors.forename: Yujun
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, P. R. China. wangchunlei@sinap.ac.cn.
authors.forename: Haiping
authors.initials: H
authors.lastname: Fang