Preparation And Properties Of Hybrid Coatings Based On Perhydropolysilazane/polyethylene Glycol

Special wetting materials can be used in extremely important and extensive application fields such as national defense industry and medicine,as well as in chemical industry,environmental protection and other industrial fields.Researchers have developed a variety of surface construction methods such as template method,self-assembly method,sol-gel method,chemical vapor deposition method,etc..But there are problems such as complex preparation process,poor mechanical properties,and unstable chemical properties.The preparation of hybrid coatings by precursor conversion has attracted much attention because of its flexible process route,in which perhydropolysilazane(PHPS)can be converted into silicon oxide coatings under relatively mild conditions.The material has excellent mechanical properties and chemical stability,and the adjustment of coating function can be realized by the design of the precursor molecular structure.Based on this,a new method is proposed to construct a submerged superamphiphobicity surface by synthesizing PHPS and polyethylene glycol(PEG)hybrid polymer and further curing.The preparation method is simple and the prepared coating has excellent comprehensive performance.The research content and results of the thesis are as follows:Preparation of SiO_x/PEG hybrid hydrophilic coating.The reaction of Si-H/Si-N and-OH was used to synthesize PEG-modified PHPS hybrid polymer precursors.The differences in hardness,thickness and wettability of hybrid coatings obtained by ultraviolet irradiation and humid heat conversion methods were investigated.The results show that both kinds of SiO_x/PEG hybrid coatings,obtained from the two conversion methods,composed of SiO_x as the main body and covalently bonded with PEG.The moist heat conversion method is conducive to the conversion of hydrophilic coatings,with the minimum water contact angle of34.9~o,excellent antifouling performance,and easily removal of oily dirt and mechanical impurities.Preparation of SiO_x/PEG submerged superamphiphobicity coating.By regulating the ratio of PHPS/PEG in the hybrid polymer precursor and converting it by ultraviolet irradiation,a Silica/PEG hybrid coating with submerged superbiphobic properties was prepared.The hybrid coating is smooth and transparent,with a surface roughness of less than 1 nm and a light transmittance of more than 90%.Other performance includes:excellent thermal stability-initial decomposition temperature of higher than 359°C;excellent adhesion with polyethylene terephthalate(PET),stainless steel,glass,aluminum plate,alumina ceramics and various substrates;high mechanical properties-its nanoindentation hardness and modulus reach 3.37GPa and 34.9 GPa,respectively.It also has good mechanical and chemical stability,and still has submerged superamphiphobicity properties after 700 times wear under load 1 N,or immersion in deionized water(30 days)and different solvents(24 h).