Preparation And Properties Of Super Hydrophilic Coatings

As a kind of special wettability materials,super-hydrophilic materials are widely used in the fields of optics,chemical industry,materials,biology,etc.,and the most common applications of super-hydrophilic materials are the anti-fog performance of transparent materials and the oil-water separation of organic substances.This paper focuses on the preparation of superhydrophilic coatings,and a simple application of superhydrophilic coatings.The main research contents and results of this paper include the following aspects:(1)Thiol-modified nano-silica was prepared by sol-gel method.After that,the hydrophilic monomer was grafted on the surface through the click reaction of thiol and double bonds,and the appropriate amount was found by discussing the addition amount of different monomers.The results showed that 2-acrylamide-2-methylpropanesulfonic acid was successfully grafted.It is branched on the surface of nano-silica to form a micro-nano structure.When the ratio of ethyl orthosilicate and(γ-mercaptopropyl)trimethoxysilane is6:1,the particle size and distribution are the most suitable.The appropriate addition amount of modified nano silica is 0.5g,and the contact angle is 4.5 °.The appropriate addition amount of waterborne polyurethane is 0.6g,the contact angle is 8.5 °,and the adhesion is grade 0.The coating hardness is 2H.(2)Modified nano-silica was prepared by sol-gel method using ethyl orthosilicate,aminopropyltrimethoxysilane,and glycidyl methacrylate was linked to nano-silica by the reaction of amino and epoxy groups The surface is made to have a double bond structure,and then the coating is obtained by copolymerizing with the acrylate monomer,and the following conclusions are obtained: it can be known that the double bond is successfully grafted on the nano-silica by infrared spectroscopy,and reacts with the acrylate monomer,and finally A polymer-nano-silica material was formed,with a maximum UV transmittance of 85.4%,good light transmittance,and a rough structure on the surface.The contact angle of water is 5°,which is a super-hydrophilic state.After 5N rubbing for 100 times,the contact angle is also less than 15°.The hardness of the super-hydrophilic coating is 6H,and the coating adhesion is grade 0.And has good anti-fog performance.(3)Grafting of 3-mercaptopropyltriethoxysilane and [2-(methacryloyloxy)ethyl]trimethylammonium chloride on the surface of nano-silica using click reaction and dehydration condensation reaction,and the superhydrophilic-air-oleophobic underwater superhydrophilic superhydrophilic-air-oleophobic superhydrophobicity was successfully prepared on the metal mesh by the reaction between the anion in sodium perfluorooctanoate and the quaternary amine cation in [2-(methacryloyloxy)ethyl]trimethylammonium chloride.The oleophobic metal mesh was used to obtain the following conclusions: SEM found that a micro-nano structure was formed on the surface of the metal mesh,the air-water contact angle was 0°,the oil contact angle in the air was 120°,the underwater contact angle was greater than 150°,and the separation efficiency was greater than 96.85%,the maximum separation flux was 23192 L/(m2 ·h),and the separation efficiency was still greater than95.65% after 30 cycles.(4)Polymethyl acrylate microspheres containing carboxyl groups on the surface were obtained by dispersion polymerization and saponification,and modified nano-silica with amine cations on the surface was prepared by the sol-gel method,which was mixed and coated on a metal mesh The superhydrophilic-underwater superoleophobic metal mesh was obtained,and the following conclusions were drawn: the polymethyl methacrylate microspheres with carboxyl groups on the surface were successfully synthesized through infrared spectroscopy characterization,and the modified nano-silica was synthesized.It can be seen from the SEM that there is a rough structure on the surface,and the size of the contact angle and the underwater contact angle shows that it has super hydrophilic and underwater super oleophobic capabilities.The measured superhydrophilic-underwater superoleophobic metal mesh separation efficiency was greater than 98.2%,and the separation flux was greater than 40127 L/(m2 ·h).The friction resistance test shows that the superhydrophilic-underwater superoleophobic metal mesh has certain friction resistance.