Preparation And Molecular Dynamics Simulation Study Of Nanocomposite Superhydrophobic Coating

In recent years, the superhydrophobic surface composite has a wide applicationprospect in basic research and industrial field thanks to its excellent self-cleaningproperties and corrosion resistance. Exploring to prepare the superhydrophobic coatingwith simple process, low cost, avirulent environmental protection, stable performanceand corrosion fouling has aroused us great interest. In this paper, a simple method for thepreparation of micro/nano dual structure superhydrophobic coating is adopted, thecoating surface morphology and performance were analyzed by scanning electronmicroscopy, infrared spectroscopy and electrochemistry workstation, the structure ofcomposite coatings and wetting properties were simulated by molecular dynamics. Thecontents and results are as follows:By taking a combination of mechanical agitation and surface modification, nanoTiO2/ZnO composite particle surface was modified with stearic acid, the compositemodified coating was prepared under such conditions: the amount of stearic acid is9%,the reaction temperature is50°C, pH=4. When the coating treatment temperature is200°C, the surface of the steel substrate to obtain the micro/nano double superhydrophobiccoating roughness showed good solvent resistance and self-cleaning properties, the staticwater contact angle is165.3°, the rolling angle is4°.The optimal conditions of ZnO particles modified with stearic acid: mass ratio of8%, temperature is40°C, pH=5. Superhydrophobic surface roughness of the dualstructure was constructed when polydimethylsiloxane/ZnO composite coating’s heattreatment temperature is120°C, the contact angle of it is161°, the rolling angle is5°,and bibulous rate is5.8%. Polydimethylsiloxane/ZnO composite coating steel sheet,whose corrosion potential is615mV and the corrosion current density is1.3×10-6A/cm2, shows great corrosion resistance performance.Using dodecafluoroheptyl-propyl-trimethoxysilane to modify the ZnO particles,then treated with polystyrene with low surface energy for preparing a superhydrophobiccoating on the steel substrate. Micro/nano double roughness superhydrophobic compositecoating was prepared when the polystyrene/ZnO mass ratio is3:7and the coating of heattreatment temperature is160°C, the contact angle is156°, the rolling angle is8°,bibulous rate is7.3%. Polystyrene/ZnO composite coating steel sheet, whose corrosionpotential is586mV, the corrosion current density is2.8×10-7A/cm2, performed goodcorrosion resistance, the oil-water separation rate of polystyrene/ZnO superhydrophobic composite coating that coated on cotton is about86%.Investigating the structure and wettability of the composite coating by moleculardynamics simulation, we found that TiO2and ZnO structure were combined by the vander Waals force crosslinking, both polydimethylsiloxane and polystyrene respectivelyadhered to the ZnO surface, covering with each other. The binding energy of TiO2/ZnOcomposite coating to the metal is minimum, while the binding energy ofpolydimethylsiloxane/ZnO composite coating or polystyrene/ZnO to the metal surfacewas relatively large. The dynamics simulation results showed that the agreement with theexperiment results was fairly good.