相分离丙烯酸树脂/SiO_2复合超疏水薄膜的制备及其性能

Preparation and Performance of Acrylic Resin/SiO_2 Composite Superhydrophobic Film Based on Phase Separation

基于溶剂诱导相分离法,将丙烯酸树脂薄膜在含有二氧化硅和异氰酸酯三聚体交联剂的乙酸乙酯(良溶剂)和乙醇(不良溶剂)的混合溶剂中浸渍提拉,获得具有多孔结构的超疏水薄膜。分别用红外光谱、扫描电镜表征了超疏水薄膜的结构和形貌,并测试了其疏水性、自清洁性及耐磨性。当混合溶剂中乙酸乙酯与乙醇的体积比为6∶4、SiO_2的质量浓度为0.025g/mL时,超疏水薄膜的水接触角可达158°±3°,且经历35个周期的砂纸磨损(100g载重)后仍保持超疏水性,具备良好的自清洁性与耐磨性。

A simple and effective approach was reported to fabricate a low-cost,environment-friendly,self-cleaning and mechanically durable superhydrophobic film.The film was prepared by dip-coating acrylic resin film in an ethanol/ethyl acetate suspension of nano SiO 2(n-SiO 2)and hexamethylene diisocyanate trimer(HDI trimer).Since the solubility of acrylic resin in ethyl acetate(solvent)differs from in ethanol(non-solvent),a porous structure was formed on the film surface based on phase separation.SEM images showed that as the volume ratio of ethyl acetate in mixture increased,the coated surfaces became fluffier and internal pores were larger.By contrast,the porous structures were more uniform and complete when the volume ratio of ethanol to ethyl acetate reached 6∶4 in solvent mixture.With a further addition of n-SiO2,the hydrophobicity of the film was greatly enhanced.Porous structures were also observed after n-SiO2 was added,and more nanoparticles were deposited on the inner wall of the holes as the content of n-SiO2 increased,which helped to form a dense nanoscale layer during phase separation process.The synergistic effect of nanoscale n-SiO2 and microscopic holes endowed the film with a remarkable superhydrophobicity(158°±3°)and self-cleaning property when 2.5g of n-SiO2 was added.Moreover,acrylic resin and n-SiO2 were further cured by HDI trimer through the reaction between isocyanate groups and hydroxyl groups,which improved the mechanical properties of the superhydrophobic film.The performance test showed that the film still kept its superhydrophobicity after 35 cycles of sandpaper abrasion under 100g of loading,indicating a pretty admirable mechanical durability.The facile preparation and high-performance of the superhydrophobic film make it quite suitable for the manufacture in a large scale,which would have extensive application prospects in the future.