Construction And Property Of Self-healing Superhydrophobic Coating Based On PDMS Self-assembled By Hydrogen Bond

Due to its excellent water repellency,superhydrophobic materials can be widely used in self-cleaning,corrosion protection,ice protection and other fields.However,in practical application,affected by chemical corrosion,scratching and wear and other external environments,superhydrophobic coatings are easy to aging,cracking and even falling off,resulting in coating failure.To solve this problem,a weather-resistant self-healing superhydrophobic surface was designed:a self-healing polymer rich in hydrogen bonds was constructed by the amide reaction of bis-aminopropyl-terminated polydimethylsiloxane（A-PDMS）and homobenzotricarbonyl chloride（TMC）,and using it as a flexible substrate and low surface energy substance;nano-silica was introduced to construct the surface rough structure to prepare the superhydrophobic self-healing coating.The main research contents and research results of this project are as follows:Hydrophobic hyperbranched polymer（HB-PDMS）with self-healing function was synthesized from homobenzotricarbonyl chloride and bis-aminopropyl-terminated polydimethylsiloxane as raw materials,and coated on the glass substrate to obtain HB-PDMS coating.When the reaction time was 5 h,the temperature was 35°C,and the molar ratio of COCl to NH₂ was 7:5,the molecular weight of the prepared hyperbranched PDMS was 96330,resulting a large branching structure.The coating has medium hydrophobic properties and excellent self-healing properties:the surface contact angle is 111.12°;mechanical damage can be repaired after only 80°C heat treatment for 2 h.Using HB-PDMS as the self-healing polymer substrate,introducing nano-silica with simple physical blending,SiO₂@HB-PDMS composite coating was obtained by impregnation and pulling method.When SiO₂ particle size is 50 nm and solids content is30 wt.%,the coating has superhydrophobic properties:contact angle is 154.87°,sliding angle is 4.05°.After 5 tape peel tests,the coating showed good mechanical stability.After10 times of temperature difference cycle test and 24 h ultraviolet light irradiation,the surface contact angle of the coating is still greater than 150°,indicating that the coating has good weather resistance.At the same time,the coating has a certain self-healing function,and some scratch damage can be repaired by heat treatment.The results of the Tafel and Nyquist tests show that the superhydrophobic treatment of the substrate can significantly improve the corrosion resistance,and the coating has a significant self-cleaning effect.With HB-PDMS as the self-healing polymer substrate and myristic acid as the hydrophobic modification of silica,the bottom-up system of"substrate-self-healing polymer-hydrophobic particles"was obtained,that is,MA-SiO₂/HB-PDMS composite coating.When the mass ratio of myristic acid to silica is 1:1 and the modification time is3 h,the contact angle of the prepared superhydrophobic coating is 152.61°,and the sliding angle is 1.9°,which has excellent self-cleaning properties.After 5 tape peel tests,linear wear tests with a wear length of 30 cm,ultrasonic shock tests of 50 min,10 temperature differential cycles and 24 h ultraviolet irradiation,the contact angle remained above 150°,indicating that the coating has good mechanical stability and weather resistance.In addition,the coating has excellent self-healing properties.Compared with pure aluminum,this composite coating has good corrosion resistance,and the corrosion inhibition efficiency can reach 87.53%.The coating is expected to be used in stain-resistant glass.