Pan Shuaijun, Guo Rui, Xu Weijian
State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
Soft Matter. 2014 Dec 7;10(45):9187-92. doi: 10.1039/c4sm01731e.
Dynamically tuning the surface wettability has long been a scientific challenge, but of great importance in surface science. Robust superhydrophobic surfaces, displaying switchable and tunable extreme wetting behaviors, are successfully developed by spraying photoresponsive hydrophobic nanoparticles onto various substrates. The surface wettability can be intelligently adjusted by applying irradiation with UV or visible light, which is assumed to initiate large conformation changes of azobenzene units at the coating surface, resulting in distinct surface energy change and thus controlled wetting behaviors. The underlying wetting mechanism about the resulting surfaces is systematically investigated and supported by the estimation of water contact angles using newly rewritten Cassie-Baxter and Wenzel relations and also by the evaluation of solid surface free energy adopting the Owens-Wendt approach. The methodology proposed may provide a novel way of tuning surface wettability and investigating the wetting transition mechanism and also promote applications in self-cleaning and smart fluid control.
长期以来，动态调节表面润湿性一直是一项科学挑战，但在表面科学中却极为重要。通过将光响应性疏水纳米颗粒喷涂到各种基材上，成功开发出了具有可切换和可调谐极端润湿行为的坚固超疏水表面。通过施加紫外线或可见光照射，可以智能地调节表面润湿性，这被认为会引发涂层表面偶氮苯单元的大构象变化，从而导致明显的表面能变化，进而控制润湿行为。利用新改写的Cassie-Baxter和Wenzel关系对水接触角进行估算，并采用Owens-Wendt方法评估固体表面自由能，对所得表面的潜在润湿机制进行了系统研究并得到了支持。所提出的方法可能为调节表面润湿性和研究润湿转变机制提供一种新途径，也有助于在自清洁和智能流体控制方面的应用。
