| At present,the researches on surface anti-oil contamination finishing and the durability of superhydrophobic cotton fabric have attracted wide attentions.Previous work focused more on the fabrication of superhydrophobic coatings,and more micro-/nano-scale hierarchical structures and low surface energy hydrophobic components have been excavated,while the coatings were limited by the complicated and long process,serious environmental pollution,high production and maintenance costs,single and limited wearability,and the poor practicability in real life.The large-scale manufacturing and applications of superhydrophobic coatings remained great challenges.In term of surface self-cleaning,the coatings tended to prevent the immobilization of water-based pollutants(milk,vinegar,soy sauce,coffee,and cola),dust,and bacteria.However,when contaminated with oils,the surfaces will quickly spread and form an oil stain,which affected the aesthetics,comfort and surface property.In recent years,some superoleophobic coatings have been fabricated.To reduce the surface energy of the coatings,fluorochemicals were inevitably used,due to extremely low surface tensions of oily substances,besides,the non-degradability and the accumulation of biological toxicity such as PFOA/PFOS,making superoleophobic coatings fall into disputes.Short-fluorocarbonchains-and carbon-/silicon-based hydrophobic components have been tried to make the surfaces oleophobic,while the surface properties were limited.Part of the work hopes to degrade oil contamination with the photocatalytic activity.Take into account the damages of UV/visible light on the hydrophobicity and substrates,it was very necessary to improve the light durability of the coatings,and the photocatalytic activity with broad spectrum absorption,high efficiency and recyclability is an urgent problem to be solved.Superhydrophobic coatings,including micro/nano-scale structures,are vulnerable to laundering and abrasion,and the coatings were sensitive to O2 plasma etching,chemical corrosion,photo-irradiation and high temperature,thus losing the superhydrophobicity.In this paper,the problem of surface oil contamination on textiles was systematically studied through surface oleophobicity to resist oil contaminations and the photocatalytic activity for degrading oil contaminations,the advantages/disadvantages of two paths were compared,and the use of fluorochemicals was avoided.A variety of stimulus responsiveness for the self-healing on superhydrophobicity against laundering,abrasion,O2 plasma etching,chemical corrosion,UV/visible light irradiation,and high temperature,were used to improve the durability of functional coatings.Besides,to shorten the process and meet the requirements of environmental protection,we tried to use waterborne coatings for preparing multifunctional superhydrophobic coatings,which can not only photocatalytic degrade oil contaminations,but also ensured the durability of functional coatings and surface coatings on substrates.The main research contents were as follows:First,surface grafting fluorinated polyhedral oligomeric silsesquioxane F-POSS superhydrophobic coating was used to repel oil contamination,and the durability of the coatings was studied.Alkali catalyzed polycondensation of trialkoxyperfluoroalkyl silane in ethanol media and UV induced thiol-ene click reaction of octavinyl POSS and perfluorodexthiol were the most mature processes for preparing-POSS derivatives.Because of its ultralow surface energy,F-POSS has usually been dissolved with expensive fluoro-solvents,which was inconvenient for industrial industrialization,and the melting temperature of F-POSS was 122-140℃,which will cause its loss during use.So,trying to polymerize/crosslink FPOSS molecules and/or directly graft F-POSS derivatives was considered to solve t he above problem.The durability of the coating can be improved by reducing the degree of fluorocarbon chain substitution of F-POSS derivatives,and surface-initiated electrochemical mediated atom transfer radical polymerization SI-eATRP reaction and subsequent triethylamine catalyzed thiol-methacrylate michael addition reaction under alkaline conditions was used to graft Poly(MAPOSS)-PFDT superhydrophobic coating,while the oil contact angle(OCA,hexadecane)can only reach 80°.Then,oil repellency of F-POSS coating can be improved by increasing the density of fluorocarbon chains,and silane coupling reaction and UV induced thiol-ene click reaction was used to graft FAS/F-POSS superhydrophobic coating.The results showed that the oil contact angle(OCA,hexadecane)can reach 120°.The coating can effectively prevent the infiltration of most oils,however,due to the lack of micro/nano-scale hierarchical structures and re-entrant textures,oil droplets can not slide spontaneously from the coating surface,and oil contamination can be removed by adsorption and wiping.Poly(MAPOSS)-PFDT and FAS/F-POSS coating had excellent washing durability,and the coatings had oven heating for the self-healing ability,which can heal the superhydrophobicity damaged by laundering,mechanical abrasion,O2 plasma etching,chemical corrosion,ultraviolet light irradiation and high temperature,based on the mechanism of heats induced the flow and migration of hydrophobic agents in the coatings and towards the surfaces,when the self-healing temperature was higher than the melting temperature Tg of hydrophobic components.Even lower heating temperature can be used for the self-healing,although the healing level will be lower.Next,the photocatalytic ability was introduced into the superhydrophobic coating to degrade oil contamination,the use of fluorochemicals was avoided,and the durability and the self-healing ability of the coatings was studied.The photocatalytic activity with broad spectrum absorption,high efficiency and recyclability was the key for degrading oil contamination,and the light durability is important.Polydopamine assisted deposition Ag-CdS photocatalyst and the grafting of 1H,1H,2H,2H-Perfluorodecanethiol(PFDT)or 1-Dodecanethiol(NDM)was used for surface superhydrophobic.The as-prepared PFDT(NDM)/Ag/CdS coating had the water contact angle(WCA)can be as high as 163° and excellent washing durability.Besides,the coatings had excellent,recyclable and washing durable photocatalytic activity,which can degrade oleic acid contamination in the UV and visible light regions and heal the superhydrophobicity,and the superhydrophobicity damaged by photo-irradiation can also be healed by heating.The grafting of 1-Dodecanethiol(NDM)had the same photocatalytic ability and superhydrophobicity as 1H,1H,2H,2H-Perfluorodecanethiol(PFDT),which meant that oil contamination can be solved by the photocatalytic activity,and fluorochemicals was avoided.Most importantly,oven heating,electro-thermal,and near-infrared photo-thermal can heal the superhydrophobicity damaged by O2 plasma etching and accelerated washing,based on the mechanism of stimulus responsiveness of functional components and heats induced the migration of hydrophobic components in the coatings and towards the surfaces.Near-infrared light photo-thermal effect enriched the self-healing methods,simplified the self-healing condition,and had the best self-healing efficiency.Finally,waterborne coatings were wet coated to prepare multifunctional superhydrophobic coatings,and long process and environmental pollution were avoided.The as-prepared coating can degrade contaminations,and the durability of multifunctional coating was studied.Inorganic nanoparticles as micro-/nano-scale structures,were usually introduced into the superhydrophobic coating to improve the mechanical property.The coating precursor PM was prepared through thiol-ene click reactions of pentaerythritol oleate(PETO)and 3mercaptopropyl triethoxysilane(MPTES)in the presence of photoinitiator 1173,and the optimized UV light irradiation time was 4 h.The coating precursor PM was added into water and emulsified to form homogeneous waterborne coating dispersions WPM.Water-dispersable nanoparticles(PTFE,TiO2 and CNTs)can improve the roughness and superhydrophobicity of the final coatings,with the water contact angle can be high as 164°,and the coatings had excellent washing durability.WPM/TiO2 coating had excellent photocatalytic activity and UV shielding performance,which can degrade contaminations and had little effect on superhydrophobicity.WPM/CNTs coating had near-infrared light photo-thermal self-healing ability and galvanostatic charge-discharge(GCD)property,which was more convenient and effective to heal the superhydrophobicity damaged by accelerated washing and mechanical abrasion,based on the mechanism that the photo-thermal effect of CNTs and heats induced the migration of hydrophobic components in the coatings and towards the surfaces.In addition,the coating also showed potential applications in wearable electronic devices. |
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