Development of polymer coatings by cold-spray

超疏水PFA涂层是通过原位超音速冲击沉积和固结的一步、快速、可扩展和无溶剂的冷喷涂技术制备的。研究工作是逐步了解涂层行为，然后逐步表征润湿行为，具体如下：1。冷喷涂含氟聚合物通过引入纳米陶瓷中间层和激光对基材表面进行纹理化，对颗粒表面形貌进行简单的修饰，使沉积效率提高到15%。所制备的涂层厚度为200微米。这种涂层可以在很高的加工速度下制造，在这种情况下，在0.1 m2的基底表面上喷涂沉积仅需要大约30秒- 1分钟。涂层与基材界面表现出激光织构的凹凸不平与涂层之间紧密的v形和泪形沟壑形成的有效互锁。润湿性能表征：涂层的接触角可达160°，滚转角可达60°，具有优异的动态拒水性。超疏水性被认为是由于由疏水纳米陶瓷层覆盖的乳头状结构组成的双重结构表面，涂层的高粗糙度以及PFA和FNA固有的低表面能和疏水性的结果。涂层表面的微观结构由乳头状PFA和一层疏水性FNA组成，形成双重结构（很像在荷叶上看到的情况）。

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 fluoropolymerSimple 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 behaviorThe 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).