Design,Fabricating And Performance Study Of High Durable Superhydrophobic Polymer Composite Coatings

Hydrophobicity refers to water contact angle on a surface is above 90°.Superhydrophobicity is defined as water contact angle above 150°and sliding angle below 10°.Superhydrophobic surfaces have prosperous applications in self-cleaning,water proof,anti-icing etc.Enhancing the mechanical abrasion ability of superhydrophobic surface is a great challenge.In this work,we aim at the actual anti-icing requirements from wind turbine blades or aircraft wings,to develop abrasion durable superhydrophobic coatings.In this work,ceria particles and fluorinated polyurethane(F-PU)resins were adopted to design novel superhydrophobic coatings.Ceria particles are intrinsically hydrophobic and mechanically robust,which are expected to enhance the mechanical durability of superhydrophobic coatings.Casting and spraying methods were applied to fabricate coatings on glass fibre reinforced epoxy composite materials,which were supposed to be more adaptive to apply in wind turbine blades.Ceria particles with different sizes and their combinations as well as resin and solvent loading were all major factors to be considered in formula design.Effect of ceria particles with diameter of 10 um,1um and 100 nm respectively and their combinations on the hydrophobicity and abrasive resistance were investigated and the coating formula was optimized.Firstly,different sizes of ceria particles were mixed with F-PU and solvents respectively and obtained coating suspension.These suspensions were casted or sprayed on the substrates to form superhydrophobic coatings.Water contact angle(WCA)was measured and used to determine optimized formula.Results show that WCA of casted coatings is 148.88° and WCA of sprayed coatings is 145.41°.Then,combination of micro ceria particles and nano particles were further used to fabricate coatings and the hydrophobicity of these coatings was evaluated.Sand impacting method was utilized to test the abrasive durability of optimized coatings.Results show that coatings fabricated with 10 um ceria particles and casting method exhibit better abrasive durability than other coatings,and the optimized ratio of F-PU and ceria particles and solvents is 0.5:0.5:1.5.Finally,SEM was used to analyze the micro morphology of the coatings fabricated with different formula and preparing processes.Results show that all the coatings fabricated in this work form micro-nano hierarchy structures and have good hydrophobicity.After sand impacting abrasion,the resin around the particles is partly peeled off and some particles exposed out from resin bulks,which lead to a better micro-nano hierarchy structure and better hydrophobicity was achieved.It was found that WCA always kept above 150°after continuously sand impacting abrasion,which indicates we can tune the abrasion resistance of the superhydrophobic coating by its thickness.