| 研究実績の概要 |
Superhydrophobic PFA coatings were fabricated by a one-step, rapid, scalable, and solventless technique called cold-spray by in-situ supersonic impact deposition and consolidation. The research work was conducted by progressively understanding the coating behavior and later on characterizing the wetting behavior step by step as following:
1.Cold spray coating of fluoropolymer
Simple modifications of particle surface morphology by introducing nanoceramic interlayers and by laser texturing the substrate surfaces to increase the deposition efficiency upto 15%. The coating fabricated was a uniform coating thickness of 200 microns. Such coatings were possible to be fabricated at great processing speeds which, in this case, was achieved in only about 30 s - 1 min of spray deposition on a substrate surface of 0.1 m2. The coating-substrate interface shows the effective interlock formed by the laser textured asperities and the coating by the tight V-shaped and tear-shaped valleys.
2.Characterization of the wetting behavior
The coatings exhibited contact angle up to 160o, roll-off angle of 6o and excellent dynamic water repellency. The superhydrophobicity was seen to be as a result of double structured surface consisting of papillae like structured capped by a hydrophobic nanoceramic layers, high roughness of the coatings and the inherent low surface energy and hydrophobicity of PFA and FNA. The microstructure of the coated surface comprised of papilla shaped PFA capped with a layer of hydrophobic FNA forming a double structure (much like the case seen on a lotus leaf).
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