School of Electrical and Electronic Engineering, Huazhong University of Science and Technology (HUST), Wuhan, 430074, China.
State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology (WUT), Wuhan, 430074, China.
Eur Phys J E Soft Matter. 2021 Mar 9;44(2):25. doi: 10.1140/epje/s10189-021-00036-7.
The droplet rolling angle is one of the important indicators to measure the coating's hydrophobic performance, but the specific factors affecting the droplet rolling angle on the micro-nanostructured superhydrophobic coating surface are not yet known. Based on the rolling mechanism of droplets on rough surfaces, and from the perspective of coating microscopic energy conservation, this paper points out that the micron-scale morphology and the nanoscale morphology can comprehensively affect the droplet rolling angle. From the above perspective, a mathematical model of the droplet rolling angle on the micro-nanostructure superhydrophobic coating surface was established. The model shows that the droplet rolling angle is positively correlated with the ratio of nano-sized pillar width to spacing, the ratio of micron-sized papilla radius to spacing, and the liquid-gas interfacial tension, and is negatively correlated to the droplet intrinsic contact angle, droplet volume and droplet density. The droplet rolling angle calculated by the presented model is in good agreement with the experimentally tested results. This model can provide good accuracy in predicting the droplet rolling angle on the micro-nanostructured superhydrophobic coating surface.
液滴滚动角是衡量涂层疏水性的重要指标之一，但影响微纳结构化超疏水涂层表面液滴滚动角的具体因素尚不清楚。本文基于液滴在粗糙表面上的滚动机理，从涂层微观能量守恒的角度出发，指出微米级形貌和纳米级形貌可以综合影响液滴滚动角。基于上述观点，建立了微纳结构超疏水涂层表面液滴滚动角的数学模型。该模型表明，液滴滚动角与纳米级支柱宽度与间距比、微米级乳突半径与间距比、液-气界面张力呈正相关，与液滴固有接触角、液滴体积和液滴密度呈负相关。提出的模型计算的液滴滚动角与实验测试结果吻合较好。该模型可以在预测微纳结构化超疏水涂层表面液滴滚动角方面提供较好的准确性。
