A modified Wenzel model for water wetting on van der Waals layered materials with topographic surfaces

Peng Zhao; Yongfeng Huang; Yutian Shen; Shuo Yang; Lan Chen; Kehui Wu; Hui Li; Sheng Meng

doi:10.1039/c7nr00521k

A modified Wenzel model for water wetting on van der Waals layered materials with topographic surfaces

Nanoscale. 2017 Mar 17;9(11):3843-3849. doi: 10.1039/c7nr00521k.

Authors

Peng Zhao¹, Yongfeng Huang¹, Yutian Shen¹, Shuo Yang¹, Lan Chen¹, Kehui Wu², Hui Li³, Sheng Meng²

Affiliations

¹ Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China. khwu@iphy.ac.cn huili8@iphy.ac.cn smeng@iphy.ac.cn.
² Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China. khwu@iphy.ac.cn huili8@iphy.ac.cn smeng@iphy.ac.cn and Collaborative Innovation Center of Quantum Matter, Beijing 100190, China.
³ Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China. khwu@iphy.ac.cn huili8@iphy.ac.cn smeng@iphy.ac.cn and Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China.

PMID: 28252149
DOI: 10.1039/c7nr00521k

Abstract

A modified Wenzel model is proposed for describing the wetting behavior of van der Waals layered materials with topographic surfaces, based on the measured linear relationship between water wetting and surface roughness for high quality Bi₂Se₃ thin films, synthesized using molecular beam epitaxy (MBE) in the optimized temperature window of 180-200 °C. The water contact angles are found to have apparent dependence on the nanoscale surface morphology, enabling film wettability as a new tool to quickly characterize the quality of atomically thin films. The water contact angle of the ideal Bi₂Se₃ surface is inferred to be ∼98.4°, indicating its intrinsic hydrophobic nature; however, the edge of the terrace on its surface is extremely hydrophilic, leading to easy hydrophobic/hydrophilic transitions. The atomistic mechanism is further revealed by first principles calculations. The regulated wettability is of great importance for electronic applications of Bi₂Se₃ and other two-dimensional materials with distinctive electronic structures.