Research On The Preparation And Durability Of Superhydrophobic Cellular Coatings

Superhydrophobic coatings have broad application prospects in the fields of anti-icing,anti-fouling,and anti-corrosion.However,there are problems such as complex preparation methods,poor wear resistance and short service life of coatings,and it is still difficult to apply them on a large scale.How to prepare long-lasting and durable superhydrophobic coatings has become one of the urgent problems to be solved.In this paper,porous ceramic particles with heterogeneous surface chemistry are used as rigid shells,and hydrophobic silica nanoparticles are used as filling seed phases to construct binary controllable superhydrophobic unit cells,on the one hand,it has a physical shielding effect against mechanical damage and provides self-healing properties,and on the other hand,it can chemically bond with the active groups in the resin,so as to obtain a coating with good superhydrophobicity and mechanical durability.The main research results of this paper are as follows:The fully modified nanoseeds are stored in the pores of the incompletely modified porous ceramic particles by mechanical stirring to prepare oil-based superhydrophobic unit cells,combined with resin,and one-step spraying to prepare oily ultra-robust superhydrophobic cellular coatings.Experiments found that when the content of nanoseeds increased,the wear resistance of the coating increased.When the content was 20 wt.%,the coating had the best mechanical wear resistance,and the thickness of 100?m could withstand a load of 1000 g for nearly 1000 r;and it can withstand30 m/s water/sand water impact for 240 hours;in addition,the coating has excellent heat resistance,acid,alkali and salt water resistance and anti-frost and condensation resistance;the hardness of the coating reaches 4 H,and the adhesion is Level 0.The excellent durability of the coating is due to the porous ceramic particles that can protect the nanoseeds,and the fully modified nanoseeds can be released during the wear process to repair and maintain the coating structure and chemical stability.Porous ceramic particles with heterogeneous surface chemistry have a large number of-OH groups remaining on the surface,which can form chemical bonds with the matrix.When the nanoseed content continued to increase,the abrasion resistance decreased instead,because excessive fully modified nanoseeds weakened the chemical bonding effect exerted by the-OH group.By adding dispersant,water-based unit cells were prepared in water solvent.The results showed that adding fluorocarbon surfactant had the best dispersing effect;when the content was too low,it was difficult to disperse,and when the content was too high,it was difficult to obtain hydrophobicity.When the content was 0.3 wt.%,the comprehensive performance is the best,and the prepared water-based unit cells have excellent dispersibility,which can be added to oil-based or water-based coatings,combined with bonding components,and can be sprayed in one step to prepare water-based ultra-robust superhydrophobic cellular coatings.Under the 1000 g load Taber abrasion test,the superhydrophobicity can still be maintained after 2200 r,and the coating can be immersed in water for 40 days and still maintain excellent superhydrophobicity.In addition,the coating has excellent temperature stability and chemical stability.The hardness reaches 5 H and the adhesion is grade 0.The excellent dispersibility is due to the reasonable addition of fluorocarbon surfactants,the chemical bonding of the-COOH group and its structural similarity with fluorosilanes,these advantages help the dispersion and grafting of components in the unit cells.Using isobutyltriethoxysilane as the bottom permeable layer,the superhydrophobic nanocoating as the middle layer,and the water-based superhydrophobic cellular coating as the top layer to prepare a multi-layer ultra-robust superhydrophobic cellular composite coating on the surface of the cement-based material,the coatings are tightly bonded,the measured surface coating adhesion can reach 3.45MPa;during the 120 h test,it does not absorb water at all,compared with the uncoated sample,the water absorption resistance is increased by 12.13%.The rapid chloride migration is about 0.92?10^-12 m²/s,which is 83.49%better than that of the sample with pure isobutyltriethoxysilane as penetrant.In addition,the coating has excellent mechanical wear resistance and weather resistance that it can withstand long-term outdoor testing.The excellent impermeability comes from the hydrophobic barrier effect of the multi-layer coating,which prevents the further penetration and damage of water and harmful ions,and realizes the durability of the multi-layer coating.