Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Nanoscale. 2017 Mar 17;9(11):3843-3849. doi: 10.1039/c7nr00521k.
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 BiSe 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 BiSe 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 BiSe and other two-dimensional materials with distinctive electronic structures.
提出了一种改进的 Wenzel 模型，用于描述具有形貌表面的范德华层状材料的润湿行为，该模型基于使用分子束外延 (MBE) 在优化的 180-200°C 温度窗口中合成的高质量 BiSe 薄膜的水润湿和表面粗糙度之间的线性关系的测量。发现水接触角明显取决于纳米级表面形态，使薄膜润湿性成为快速表征原子级薄膜质量的新工具。推断理想 BiSe 表面的水接触角约为 98.4°，表明其固有疏水性；然而，其表面台地的边缘极具亲水性，导致容易发生疏水性/亲水性转变。原子机制进一步通过第一性原理计算揭示。润湿性的调节对于 BiSe 和其他具有独特电子结构的二维材料的电子应用非常重要。
