The Preparation And Properties Of Silicone-based Acrylate Superhydrophobic Composite Coating

The superhydrophobic coating derived from the lotus leaf self-cleaning effect has attracted wide attention because of its great role in aircraft anti-icing,chemical engineering anticorrosion,building self-cleaning and environmental protection oil and water separation.However,although numerous synthetic and manufacturing methods have successfully obtained superhydrophobic coatings,the inherent vulnerability of the fine surface texture of superhydrophobic coatings has created layers of obstacles to the development of superhydrophobic coatings,resulting in the bottleneck of its application in many fields.Therefore,the aim of this work is to improve the mechanical stability of superhydrophobic coating.From the perspective of molecular structure design,the coating with good water resistance can be developed,in order to maintain excellent durability under the enhanced corrosion environment and various mechanical wear.Firstly,hyperbranched polysiloxane hybrid silica nanoparticles（HBPSi@Si O₂）were synthesized by a conventional sol-gel method using octyltriethoxy-silane（OTES）and tetraethyl orthosilicate（TEOS）.In addition,an acrylic matrix resin（PMS）containing active siloxane and low surface energy siloxane was prepared by substituting dimethyl-dimethylsiloxane（PDMS）with methylacryloxy triethoxysilane（MPS）and then taking part in radical polymerization with octadecyl methacrylate（SMA）and methyl methacrylate（MMA）.Then,the above two are mixed proportionally and sprayed to construct the super water-repellent coating（TOP）with good comprehensive performance.On the one hand,the silicone acrylate copolymer containing active siloxane group contains low surface energy PDMS,and siloxane can be further bonded with the substrate surface hydroxyl and HBPSi@Si O₂;On the other hand,HBPSi@Si O₂ contains a large number of highly active silanol and siloxane groups,which can not only form stable covalent bonding with the substrate and copolymer,but also can be closely combined with the micro/nano structure of silicon dioxide through Si-O-Si covalent bond,so as to achieve good compatibility and firm bonding with the matrix.The results show that the superhydrophobic coating has a static water contact Angle up to 158°and a sliding Angle down to 4°.It can maintain excellent water resistance after 100 times of wear of circulating sandpaper,40 times of tape stripping and 200 g of sand impact.In addition,the coating can be further applied to resist insect blood adhesion under dynamic conditions,self-cleaning of contaminants in life,and substrate surfaces with different properties.Secondly,polytetrafluoroethylene nanoparticles（PTFE）with good hydrophobicity without further modification were added to the above-mentioned successfully prepared silicone-based acrylic copolymer,and a super-hydrophobic coating（PMS@PTFE）was also constructed by simple spraying process.In the process of film formation,the siloxane groups carried by the silicon-based acrylic copolymer will hydrolyze and condense,providing good substrate adhesion and embedding nanoparticles in the substrate;PTFE provides super-hydrophobic texture and low surface energy.The results show that the static water contact angle of the coating can reach 159,and the rolling angle can be as low as 2.The coating can still have tenacious superhydrophobicity in 90℃boiling water,150℃ambient temperature,168 h ultraviolet irradiation and immersion in strong acid/alkali environment for several days.It can withstand 80 cycles of abrasive paper abrasion,30 times of tape peeling and 160 g sand impact,and still has good water repellency.In summary,based on the molecular structure,this paper constructs a low surface energy silicon-based acrylic matrix resin with strong bonding and solid interface,and combines it with hyperbranched polysiloxane and nanoparticles to construct a superhydrophobic coating successfully.It has advantages of good mechanical and chemical tolerance and excellent self-cleaning,and has unique advantages in extendable production technology,less equipment requirements and mild process conditions,which provides a new idea and theoretical method for the subsequent construction and application of superhydrophobic coatings.