Fabrication And Application Of Superhydrophobic Biomimetic Materials

Superhydrophobic surface refers to a surface having a contact angle greater than 150 ° and a rolling angle of less than 10 °.With the development of society and the advancement of technology,materials with superhydrophobic property have attracted more and more attention because of their unique performance and promising applications in paper-making and priting industry.Research on the microstructure of natural superhydrophobic surface showed that the construction of surface microstructure with certain roughness is an important way to obtain superhydrophobic surface.Therefore,based on the review of the existing literatures,from the perspective of surface roughness structure,several funtional surfaces with special wettability were designed.The wetting performance of the corresponding surface and its application in oil/water separation were also studied.The main contents and innovations are listed as follows:(1)A facile and environmental friendly method was reported for the fabrication of superhydrophobic surface.PS particles of 1 ?m and 200 nm were first synthesized via dispersion polymerization and emulsion polymerization,respectively.The obtained PS particles were then used as template for the silification using tetraethyl orthosilicate as the precursor.After treated with HDTMS,the PS@SiO2 particles were deposited on steel mesh forming dual-sized hierarchical structures.The as-prepared film exhibited excellent oil/water separation ability.This facile synthesis strategy for fabricating multifunctional steel mesh provides potential applications in large-scale oil/water separation.(2)Inspired by “lotus effect”,we proposed a facile synthetic route toward raspberry-like PS@SiO2 particles.In this approach,monodisperse polystyrene(PS)particles were first synthesized via dispersion polymerization using polyvinylpyrrolidone(PVP)as stabilizer.The obtained PS particles were then used as template particles for the biomimetic silification using tetraethyl orthosilicate(TEOS)as precursor.Upon adjusting the molecular weight and content of PVP,the concentration of TEOS,the reaction temperature and NH3·H2O,the surface roughness of PS@SiO2 particles can be well controlled.After surface modification the raspberry-like PS@SiO2 particles with HDTMS,dual-scale superhydophobic film was obtained,which is similar to the surface morphology of lotus leaf.Furthermore,after modification sponge with the superhydrophobic raspberry-like particles,the sponge exhibited excellent oil/water separation ability.The present method has mild reaction condition,simple operation,no VOC emission and has high industrial practicability.(3)Raspberry-like PS/PGMA organic/organic microspheres were prepared by two-step dispersion polymerization and then were used for the construction of superhydrophobic coatings.In this two-step dispersion polymerization,St was used as the reaction monomer,glycidyl methacrylate(GMA)was used as functional monomer,divinylbenzene(DVB)was used as crosslinking agent.The surface morphology and roughness can be well controlled by adjusting the ratio of ethanol to water,the amount of initiator,the functional monomer and crosslinking agent.The as prepared raspberry-like PS@PGMA microspheres had a good morphology and relative uniformed particle size.Compare to other methods,this one-pot polymerization method for raspberry-like particles are simpler and more efficiency.The present method has mild reaction condition,simple operation and has high industrial practicability for the preparation of superhydrophobic coatings.(4)A facile and versatile strategy was presented to fabricate robust and superhydrophobic/superoleophilic cotton for the removal of oils and organic solvents from polluted water.The superwettability cotton was prepared via in situ hydrolysis of tetraethoxysilane(TEOS)on the cotton fiber surface using polyvinylpyrrolidone(PVP)as coupling agent and subsequent HDTMS modification.The prepared cotton fibers were used as superabsorbents for oil/water separation.It absorbed up to 35 times and 50 times its own weight of n-hexane and chloroform,respectively,while repelling water completely.Moreover,the whole procedure was carried out in a mild environment,with no intricateinstruments or toxic reagents.(5)Castor oil-based mercaptopropionate was used as the base resin,the nano-silica particles was used as inorganic filler for the the preparation of wear-resistant self-cleaning coating.In detail,CO-SH was synthesized via esterification reaction between castor oil(CO)and 3-mercaptopropionic acid(MPA)as a self-initiated oligomer for photoinitiator(PI)-free UV coating.Then CO-SH and silica were dissolved in acetone solution and ultrasonic dispersed for at least 2 hours.The resulting solution was then spin-coated onto glass slides and other substrates to form superhydrophobic surface.Castor oil-based mercaptoacrylates used as organic resin can not only provides low surface energy for the hydrophobic surface,but also can binds the nano-silica to the substrate as an adhesive so as to enhance the adhesion property of the coating.The effects of various factors on the coating properties were investigated.The morphology of the as prepared coating and the water contact angle of the coating surface were also characterized.