The Surface Force Analysis Of Self-Cleaning Effect On Superhydrophobic Surface

There are many natural phenomena relevant with superhydrophobicity. Lotus, a plant lives in the lilt without imbruing itself. Water skipper, an insect moves as easily as on firm earth. All these self-cleaning feature concerning with superhydrophobic (SH) surface have attracted extensive attentions. As the rapid development of micro-technique, it becomes possible to observe the microstructure on the surface. Many researches indicate that binary microstructure which exists on the surface of Lotus is the key to superhydrophobicity. Besides, there are also many applications like self-cleaning, anticorrosion, oil-water separation, textile clothes as well as fluid drag reduction deriving from the wettability of SH surface. Many investigations reveal that rough surface structures and low surface free energy make up the requirements to fabricate SH surface. Based on this, scientists designed more methods as etching, template, phase separation and sol-gel method to fabricate SH surface. To realize the process of self-cleaning on the SH surface, it requires both the mechanical analysis on the interaction between particle and liquid drop as well as the analysis on the relationship between self-cleaning and the particle mass. Nevertheless, neither of them is reported by now.In this paper, it will firstly measure the adhesion force on the SH surface and hydrophilic surface. Following this, it will perform a mechanical analysis over the interaction between the micro-particle and the liquid drop. According to this, it will come to the reason how SH surface realizes self-cleaning. Furthermore, it will discuss the relationship between realization of self-cleaning and the particle mass. At last, it will calculate the critical radius of particles which realize the self-cleaning based on the mechanical analysis. Combining with the proof test on the fresh lotus, it perfectly matches the calculations.Seen from the tests and the calculations, there are several results as follow:1. The adhesion force of SH surface is much less than hydrophilic surface and hydrophobic surface. 2. A force mechanism of realizing self-cleaning on SH surface is proposed.3. According to the tests, we found the relationship between the realization of self-cleaning and the particle mass. Particles of different quality to achieve the clean in a different way.4. We carried out theoretical predictions and experimental verification for self-cleaning critical particle radius, found that theoretical and experimental results can be a very good match..