Spray-coating process in preparing PTFE-PPS composite super-hydrophobic coating

Abstract

In order to improve the performance of a liquid-floated rotor micro-gyroscope, the resistance of the moving interface between the rotor and the floating liquid must be reduced. Hydrophobic treatment can reduce the frictional resistance between such interfaces, therefore we proposed a method to prepare a poly-tetrafluoroethylene (PTFE)-poly-phenylene sulphide (PPS) composite super-hydrophobic coating, based on a spraying process. This method can quickly prepare a continuous, uniform PTFE-PPS composite super-hydrophobic surface on a 2J85 material. This method can be divided into three steps, namely: pre-treatment; chemical etching; and spraying. The total time for this is around three hours. When the PTFE concentration is 4%, the average contact angle of the hydrophobic coating surface is 158°. If silicon dioxide nanoparticles are added, this can further improve the adhesion and mechanical strength of the super-hydrophobic composite coating. The maximum average contact angle can reach as high as 164° when the mass fraction of PTFE, PPS and silicon dioxide is 1:1:1.

Effects of pressure on wetted area of submerged superhydrophobic granular coatings. Part II: poly-dispersed coatings

“…Eq. (1) can be rearranged for a mono-dispersed coating at its CCP to read as: P cr m = 4sin˛c r cos 3 2 − Â − ˛c r d 2 6 m − sin 2˛c r (2) where m = 6 d Lm 2 is the SVF of the mono-dispersed coating. As mentioned in Part I, for mono-dispersed coatings with constant YLCAs, the critical IA, ˛c r , is independent of particle size (depends only on the SVF) [10].…”

“…The reduced cost of manufacturing has played an important role in making spray-on granular superhydrophobic coatings attractive alternatives to superhydrophobic surfaces produced via microfabrication (see e.g., [1][2][3]). Such surfaces can be used for applications ranging from self-cleaning and drag reduction to corrosion resistance and heat transfer [4][5][6][7].…”

Superhydrophobicity and Durability in Recyclable Polymers Coating

“…In general, two are the main approaches: roughening a PTFE surface to achieve the superhydrophobicity, such as by plasma etching [42], templating [43], sand paper [44], sanding [45], laser technologies [46][47][48]; or by deposition on substrate of a thin film of PTFE by a pulsed laser deposition [49], RF plasma sputtering [50], RF-magnetron sputtering [51], supercritical CO 2 [52], electrospinning [53], and chemical vapor deposition (CVD) [54]. Today, spray coating is not widespread; however, this method has the advantage of being simple, with a high efficiency and obtaining a good hydrophobicity and, when used, a final heat treatment is often required [55,56].…”

Chemical stable, superhydrophobic and self-cleaning fabrics prepared by two-step coating of a polytetrafluoroethylene membrane and silica nanoparticles

“…For instance, a large number of low surface tension polymer membranes, such as acrylics, fluorinated polymers and siloxanes, have been synthesized and applied in superhydrophobic surfaces. 14,19–22 On the other hand, superhydrophobicity can be further enhanced by hierarchical roughness on the substrate with nanoparticles (e.g., SiO 2 , 16,23–25 TiO 2 , 26 ZnO 27,28 ) through techniques such as chemical vapor deposition, 29 wet-chemical coating, 30 chemical bonds, 31,32 etc. SiO 2 nanoparticles have a large specific surface area and good dispersion performance.…”