When and how self-cleaning of superhydrophobic surfaces works
When and how self-cleaning of superhydrophobic surfaces works
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DOI：
10.1126/sciadv.aaw9727
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发表时间：
2020-01-01
期刊：
影响因子：
13.6
通讯作者：
Vollmer, Doris
中科院分区：
文献类型：
--
作者：
Geyer, Florian;D'Acunzi, Maria;Vollmer, Doris
尽管人们对超疏水性的自清洁有极大的兴趣，但对污染物去除的清晰图景仍然缺失，特别是在单颗粒水平上。在这里，我们通过共聚焦显微镜监测单个污染物颗粒在微米尺度上的去除。我们将这种空间和时间分辨的信息与摩擦力的测量结果联系起来。液滴与基材上的污染物之间的毛细管力和附着力的平衡决定了自清洁过程中液滴的摩擦力。这些摩擦力在微牛顿的范围内。我们发现，只要颗粒尺寸超过孔径或污染物厚度低于突出物的高度，亲水和疏水颗粒对超疏水性几乎没有影响。这些关于自清洁的详细见解允许合理设计抗污染的超疏水表面，如室外环境（bbb200天）和工业标准化污染实验所证明的那样。
Despite the enormous interest in superhydrophobicity for self-cleaning, a clear picture of contaminant removal is missing, in particular, on a single-particle level. Here, we monitor the removal of individual contaminant particles on the micrometer scale by confocal microscopy. We correlate this space- and time-resolved information with measurements of the friction force. The balance of capillary and adhesion force between the drop and the contamination on the substrate determines the friction force of drops during self-cleaning. These friction forces are in the range of micro-Newtons. We show that hydrophilic and hydrophobic particles hardly influence superhydrophobicity provided that the particle size exceeds the pore size or the thickness of the contamination falls below the height of the protrusions. These detailed insights into self-cleaning allow the rational design of superhydrophobic surfaces that resist contamination as demonstrated by outdoor environmental (>200 days) and industrial standardized contamination experiments.