Self-cleaning of superhydrophobic nanostructured surfaces at low humidity enhanced by vertical electric field
Yijie Liu, Yujun Guo, Xueqin Zhang, Guoqiang Gao, Chaoqun Shi, Guizao Huang, Pengli Li, Qi Kang, Xingyi Huang, Guangning Wu
Abstract
Self-cleaning is the key factor that makes superhydrophobic nanostructured materials have wide applications. The self-cleaning effect, however, strongly depends on formations and movement of water droplets on superhydrophobic nanostructured surfaces, which is greatly restricted at low humidity (< 7.6 g·kg−1). Therefore, we propose a self-cleaning method at low humidity in which the pollution is electro-aggregated and driven in the electric field to achieve the aggregation and cleaning large areas. The cleaning efficiency of this method is much higher than that of water droplet roll-off, and will not produce “pollution bands”. A simplified numerical model describing pollution movements is presented. Simulation results are consistent with experimental results. The proposed method realizes the self-cleaning of superhydrophobic nanostructured surfaces above dew point curve for the first time, which extends applications of superhydrophobic nanostructured materials in low humidity, and is expected to solve self-cleaning problems of outdoor objects in low humidity areas (< 5.0 g·kg−1).