Design And Performances Of The Hydrophilic/Oleophobic Solvent-Responsive Coatings

The low surface tension of oil drops tends to adhere to the surface,the oil residue is hard to wash off,resulting the human production and life being susceptible to oil contamination.Because the majority of oil contamination started at the surface interface,the regulation and modification of the surface structure and composition can significantly reduce oil contamination.Therefore,the development of durable,efficient,mass production coatings has good application potential in the fields of anti-fouling,self-cleaning,anti-corrosion,oil-droplets transportation,and oil-water separation.Oleophobic coatings are composed of re-entrant surface topography and low surface energy materials.However,the re-entrant surface topography of oleophobic coatings is usually accompanied by problems such as complex preparation process,poor stability,low transmittance,and unfavorable industrial production.Recently,hydrophilic-oleophobic coatings have become the focus of academic and industrial attention due to their excellent properties of oil-water separation,oleophobic,anti-biological adhesion and anti-corrosion.There are significant differences in surface energy and mechanisms between hydrophilic and oleophobic coatings.Hydrophilic surfaces with extremely high surface tension are more likely to adhere to oil droplets,resulting in a series of oil pollution problems.Therefore,it is extremely challenging to achieve both hydrophilic and oleophobic properties on the same surface.In recent years,the preparation of hydrophilic-oleophobic coatings has made a great process.Among them,as an anti-fog self-cleaning surface,the hydrophilic-oleophobic coating plays a crucial role in achieving the normal function of goggles,medical abdominal gastroscopes or other special optical lenses.Various strategies have been developed and successfully constructed hydrophilic-oleophobic coatings on inorganic and organic-based materials.However,there are still some problems such as poor mechanical durability,complex preparation process and poor transmittance due to the existence of micro-nano structure.Therefore,improving the high stability of the coating,simplifying the preparation process,reducing the preparation cost and improving the high transparency of the coating is the key to promote the application of the hydrophilic and oleophobic field.The solvent-responsive hydrophilic-oleophobic coatings were prepared by a simple,efficient and mass-prepared technique.Unlike the traditional coating with a single wettability,we reported a stimuli-responsive antifogging/oil-repellent coating with a delicate balance between hydrophilic and oleophobic components.The main research contents are as follows:1.The ingenious combination of rough structure and low-surface-energy materials produces a slippery liquid-infused porous surface(SLIPS)oleophobic coating.The dense metal-organic frameworks(MOFs)ZIF-L porous layers were successfully grown on the surfaces of different substrates by secondary growth.The low surface energy of perfluorooctanoic acid sodium salt(C₈F₁₅Na O₂)was perfused into the ZIF-L layer to obtain the ZIF-L-F coating.The coating achieves different wettability of hydrophilic and oleophobic on the same surface.After absorbing water,forming a hydration layer can realize directional transportation of oil droplets and efficient separation of oil and water.This strategy has good universality and can be stably assembled on the substrate surface of different materials and geometric shapes.2.By balancing and adjusting the proportion of hydrophilic and oleophobic segments, an antifogging coating with high transparency and excellent oil-repellent properties was developed.Owing to the high water-absorbing capacity of PAA,the coating exhibit excellent antifogging properties,in a wide temperature range from-20?to 85?.The introduction of low surface energy fluoride endows the coating with excellent oil repellency.By introducing a photoinitiator into the polymer,the polymer chain was covalently anchored to the substrate via the UV-assisted cross-linking method,which significantly improved the adhesion between the coating and the substrate,and greatly enhanced the stability of the coating.