Hydrophobic Resin-based Superhydrophobic Surface: Preparation,Application And Characterization

In recent decades,research on superhydrophobic surfaces has developed rapidly.In contrast,the conversion from research results to practical applications is very limited,which still faces difficulties such as high cost and insufficient durability.Based on bionic theory and surface wetting mechanism,two low-cost,high-performance common hydrophobic resins were chosen as the basic materials in this work,and were used to prepare surface materials with high superhydrophobicity and good practical properties.In addition,the current non-uniformity of performance evaluation test methods in superhydrophobic materials research makes it difficult to compare the scientific results,which hinders the development in this area.Some key issues of the test methods were investigated.The specific research contents and results are as follows:1.The hydrophobic resin polyvinylidene fluoride-hexafluoropropylene(PVDF-HFP)was dissolved in dimethylformamide(DMF),and one-component base films were prepared on glass slides by scraping and direct drying method.Then,the hydrophobic silica nanoparticles were sprayed on the base films to prepare superhydrophobic composite coating films with high transparency.By changing the concentration of coating solution,the size of the polymer microspheres constituting the base film would be different.The addition of non-solvent distilled water to the coating solution could slightly increase the water contact angles on the base films,and the addition of polymethyl methacrylate(PMMA)could significantly enhance the adhesion of base films to glass substrates.2.Polydimethylsiloxane(PDMS) was used as the basic material to modify the hydrophilic fabrics by emulsion dip coating method or non-solvent induced phase transformation method.And self-cleaning,antifouling superhydrophobic fabrics were obtained,which retained their original colors.According to the characterization results of fabrics and emulsions,it was inferred that the distributed curing of small PDMS droplets increased the surface roughness of the coating,making the fabrics superhydrophobic.The effect of the composition ratio of emulsion on the performance in the dip coating method was studied.And the surface roughness of the fabric was increased by adding nanoparticles to the emulsion,thereby enhancing the superhydrophobicity of the fabric.3.The effect of different droplet volumes on the contact angle measurement at the same location on superhydrophobic surface was investigated.The results showed that in the range of 5?50 ?L,the contact angles decrease with the increase of water droplet volume,and the total decline could be about 15°.The reason for the decrease in the contact angle value might be that the increase in gravity caused changes of the wetting state of water droplet to superhydrophobic surface.The ratio of water droplet size to the whole image during measurement also affected the results.The abrasion test of super-hydrophobic fabrics was carried out using different types of sandpaper.As the cycles of abrasion increased,the contact angles on fabric surfaces decreased first and then stabilized to a range of 145°?150°.Generally,the smaller the grit size of sandpaper,the more cycles of abrasion required to achieve the stabilized range.There were also differences in the way the fabric fibers were broken when the grit size changed.