Research On The Preparation And Properties Of UV-cured Superhydrophobic Composite Coatings

Super hydrophobic materials with unique wetting properties have been rapidly developed for their applications in many fields,including ice-retardant coating,self-cleaning,anti-corrosion,biomedical,surface pattern,novel transportation devices,oil-water separation and so on.However,most of the fabricating processes of the super hydrophobic materials are complicated,especially when fluorine-containing polymers are used as raw material,leading to their high cost and toxicity to living creature.On the other hand,the durability of the present super hydrophobic materials is poor,which could not meet the need of the practical application.Therefore,a facile,low cost and environmentally friendly method to fabricate robust super hydrophobic materials has been highly desirable.Polydimethylsiloxane?PDMS?is a kind of cheap and fluorine-free polymer with good hydrophobic property,mechanical and chemical stability.It can be bonded to the substrate after curing even if no adhesive.These properties make it suitable for preparing a robust super hydrophobic surface.The main contents of this research are as follows:First,a UV curable PDMS/PETA prepolymer with hexavinyl functional group was successfully synthesized using hydroxyl-terminated polydimethylsiloxane?PDMS-OH?,isophorone diisocyanate?IPDI?and pentaerythritol triacrylate?PETA?.The structure and storage stability of PDMS/PETA prepolymer were investigated by FTIR,¹H NMR and appearance observation,respectively.Then,photoinitiator and solvent were added into the prepolymer to form the PDMS/PETA coating.Finally,the cotton fabric was immersed into the PDMS/PETA coating for 1h,took out,dried and UV cured,and the super hydrophobic cotton fabric was obtained.The structure and properties of the super hydrophobic cotton fabric were characterized by FTIR-ATR,XPS,SEM,AFM,TGA,friction,washing,soaking in different pH solutions and oil-water separation test.The results shown that the obtained cotton fabric had good super hydrophobic properties,thermal stability,mechanical and chemical stability.And it also had good separation efficiency?>99%?and high stability?separation efficiency>98%after 30 recycle times?over repeated use.In order to enhance the adhesion between the substrate and the as-fabricated super hydrophobic coatings,the super hydrophobic V-PDMS/ODA coating with flower clusters-like hierarchical structure was prepared by vinyl-terminated polydimethylsiloxane?V-PDMS?and octadecylamine?ODA?.Then,the super cotton fabric was fabricated by being coated wih V-PDMS/ODA coating.FTIR-ATR,XPS,SEM and EDS were used to characterize the structure and microscopic morphology of the super hydrophobic PDMS/ODA-fabric.The adhesive fastness between the PDMS/ODA coating and the cotton fabric was investigated by water impacting,tube brushing,knife scraping,twisting,finger pressing and tape peeling.Moreover,the mechanical abrasion,continuous NaCl solution rinsing and chemical durability of PDMS/ODA-fabric were also evaluated.The experimental results shown that the adhesive fastness between the PDMS/ODA coating and the cotton fabric was strong and the PDMS/ODA-fabric owned excellent physical and chemical stability.The properties of the self-cleaning,oil-water separation and oil collection of PDMS/ODA-fabric was evaluated by KMnO₄ powder contaminant removal and oil absorption test,respectively.The experimental results indicated that PDMS/ODA-fabric had good self-cleaning ability and good oil absorption performance.As to the different viscosities and densities of oil or organic solvent,the weight gains of PDMS/ODA-fabric was from 138 to 380%.It will become a kind of new material for oil-water separation and oil collection.To further improve the mechanical stability of the super hydrophobic cotton fabric,the mMoS₂/V-PDMS coating was prepared.First,MoS₂ was modified by KH-570,and the vinyl-functionalized MoS₂ was prepare.The contact angle test,dispersibility in water,FTIR and XRD were used to characterize the modified MoS₂.The results shown that MoS₂ was successfully modified and its hydrophobicity was enhanced.Then,the obtained mMoS₂ was introduced into the V-PDMS.Finally,the super hydrophobic cotton fabric was fabricated by dip-coating and UV curing method.FTIR-ATR was used to investigate the structure of the obtained cotton fabric.SEM and EDS were used to characterize the surface microscopic morphology and element distribution.The results shown that the mMoS₂/V-PDMS coating had been successfully introduced onto the surface of the cotton fabric.After the different temperature treatment,different solution soaking and rubbing test,the prepared cotton fabric exhibited excellent stability.The oil-water separation ability of super hydrophobic cotton fabric was studied by different oil-water separation operating means?oil absorption and gravity driven separation?.The coated cotton fabric could be used as both absorbent and gravity-driven separation device for oil-water separation with separation efficiency all over97%.Additionally,the super hydrophobic cotton fabric still maintained high separation efficiency?the separation efficiency was above 96.5%after 25 separation cycles?,showing excellent reusability.Therefore,it has great development prospect in the water treatment and industrial sewage disposal.