Wong William S Y, Corrales Tomas P, Naga Abhinav, Baumli Philipp, Kaltbeitzel Anke, Kappl Michael, Papadopoulos Periklis, Vollmer Doris, Butt Hans-Jürgen
Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128, Mainz, Germany.
Department of Physics, Federico Santa María Technical University, Avenida España 1680, Casilla 110-V, Valparaíso, Chile.
ACS Nano. 2020 Apr 28;14(4):3836-3846. doi: 10.1021/acsnano.9b08211. Epub 2020 Feb 28.
Superamphiphobic surfaces are commonly associated with superior anticontamination and antifouling properties. Visually, this is justified by their ability to easily shed off drops and contaminants. However, on micropillar arrays, tiny droplets are known to remain on pillars' top faces while the drop advances. This raises the question of whether remnants remain even on nanostructured superamphiphobic surfaces. Are superamphiphobic surfaces really self-cleaning? Here we investigate the presence of microdroplet contaminants on three nanostructured superamphiphobic surfaces. After brief contact with liquids having different volatilities and surface tension (water, ethylene glycol, hexadecane, and an ionic liquid), confocal microscopy reveals a "blanket-like" layer of microdroplets remaining on the surface. It appears that the phenomenon is universal. Notably, when placing subsequent drops onto the contaminated surface, they are still able to roll off. However, adhesion forces can gradually increase by up to 3 times after repeated liquid drop contact. Therefore, we conclude that superamphiphobic surfaces do not warrant self-cleaning and anticontamination capabilities at sub-micrometric length scales.
超双疏表面通常具有卓越的抗污染和防污性能。从视觉上看，这是由于它们能够轻松地使液滴和污染物脱落。然而，在微柱阵列上，已知当液滴前进时，微小的液滴会留在柱的顶面。这就提出了一个问题，即即使在纳米结构的超双疏表面上是否也会有残留物。超双疏表面真的是自清洁的吗？在这里，我们研究了三种纳米结构超双疏表面上微滴污染物的存在情况。在与具有不同挥发性和表面张力的液体（水、乙二醇、十六烷和离子液体）短暂接触后，共聚焦显微镜显示表面上残留有一层“毯子状”的微滴。看来这种现象是普遍存在的。值得注意的是，当在受污染的表面上放置后续液滴时，它们仍然能够滚落。然而，在反复进行液滴接触后，粘附力可能会逐渐增加多达3倍。因此，我们得出结论，在亚微米长度尺度上，超双疏表面并不具备自清洁和抗污染能力。
