College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou, China, 310014.
College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing, China, 100029.
ACS Appl Mater Interfaces. 2020 Nov 25;12(47):53394-53402. doi: 10.1021/acsami.0c13477. Epub 2020 Nov 11.
Recently, the antisoiling performances of superhydrophobic (SH) surfaces have received much attention due to their potential applications in self-cleaning photovoltaic glass and other surfaces without the need to be rinsed with water. In this work, we systematically compared the antisoiling performances of lotus leaf and other plant leaves by first drying them in the shade and then placing them outdoors in a slight breeze for 1-2 months. The results show that after being dried in the shade, the lotus leaf and the canna leaf retain their SH properties, comparable with their fresh states. The firmiana leaf is still hydrophilic. However, when the leaves are exposed to rain, no rain drops adhere to the surface of the lotus leaf but many droplets adhere to the canna leaf. Furthermore, after being incubated outdoors in the absence of rain for 1 month, the lotus leaf retained its SH properties, the canna leaf was no longer SH, and the firmiana leaf became more hydrophilic. SEM imaging with EDS and elemental mapping all confirmed that after outdoor exposure for 1-2 months, only a small amount of dust was found on the lotus leaf but a significant amount of dust was present on the canna leaf, with even more on the firmiana leaf. These results confirm that the lotus leaf has excellent antisoiling performance. The low interactions between the lotus leaf surface and the dust particles are most likely responsible for this unique property. On the contrary, the canna leaf, and especially the firmiana leaf, do not possess this property because neither their surface microstructures nor their surface free energies are favorable to reduce interactions between the leaf surface and dust particles. This study will be helpful in designing and preparing a surface with antisoiling performance.
最近，由于具有自清洁光伏玻璃和其他无需用水冲洗表面的潜在应用，超疏水（SH）表面的防污性能受到了广泛关注。在这项工作中，我们通过首先将它们在阴凉处干燥，然后将它们放置在微风中户外 1-2 个月，系统地比较了荷叶和其他植物叶片的防污性能。结果表明，在阴凉处干燥后，荷叶和美人蕉叶保持其 SH 特性，与新鲜状态相当。梧桐叶仍然亲水。然而，当叶子被雨水淋湿时，荷叶表面没有雨滴附着，但美人蕉叶上有许多雨滴附着。此外，在户外无雨的情况下孵育 1 个月后，荷叶保持其 SH 特性，美人蕉叶不再具有 SH 特性，梧桐叶变得更加亲水。SEM 成像与 EDS 和元素映射都证实，在户外暴露 1-2 个月后，荷叶上只有少量灰尘，而美人蕉叶上有大量灰尘，梧桐叶上的灰尘甚至更多。这些结果证实了荷叶具有优异的防污性能。荷叶表面与灰尘颗粒之间的低相互作用很可能是造成这种独特特性的原因。相反，美人蕉叶，特别是梧桐叶，不具有这种特性，因为它们的表面微观结构和表面自由能都不利于减少叶片表面与灰尘颗粒之间的相互作用。这项研究将有助于设计和制备具有防污性能的表面。
