Fabrication And Properties Of Hydrophobic Materials Based On Nano-Precise Coating Of Nature Cellulose Materials

Superhydrophobic, Superoleophobic materials with excellent self-cleaning effect have great potential applications in fundamental researches and industrial areas. Inspired by natural superhydrophobic lotus leaf surface, researchers have paid great attentions to the design, fabrication and research of the superhydrophobic materials. Cellulose materials were one of the most abundant organic raw materials. Cellulose materials, such as filter paper, cotton, cloth, and so on, are composed of randomly cross-liked micro-and nano fibers, which show the natural hierarchical structure with surface roughness. Additionally, Cellulose materials are biodegradable and mechanically flexible biopolymers. Therefore, there are great advantages to use the cellulose materials as the substrates to fabricate superhydrophobic materials.Herein, cellulose material was chosen as the substrate material, Cellulose substance with reversible photo-responsive wettability and amphiphobic cellulose substance with antibacterial property were fabricated by combination of surface sol-gel and self-assembly method; Meanwhile, an another surperhydrophobic material was prepared by combination of surface sol-gel, crystalization and self-assembly method. The main contents and conclusions are as followed:1. The fabrication of hydrophobic material with reversible photo-responsive wettability based on the natural cellulose substance. A highly hydrophobic cellulose materials were prepared by self-assembling of7-[(trifluoromethoxyphenylazo)-phenoxy] pentanoic acid (CF3AZ0) mo no layer onto titania ultrathin film pre-coated nanofibre surfaces of commercial laboratory filter paper. The as-prepared CF3AZO monolayer modified filter paper showed approaching superhydrophobicity, and it transited to extremely hydrophilic state after being exposed to UV light (λ=365nm) irradiation, and the original surface wettability recovered after dark storage. The conformational transformation of the photo-sensitive CF3AZO molecules during UV irradiation and dark storage was related to the reversible wettability. Titania gel layer deposited on the nanofibre surfaces of filter paper, compared with silica gel layer, was more active for assembly of CF3AZO molecules, and the hydroxyl moieties implanted on the surface of titania gel layer during UV irradiation and their substitution by oxygen in dark demonstrated synergic effect on tailoring surface wettability.2. The fabrication of amphiphobic material withantibacterial property based on the natural cellulose substance. Cellulose materials with amphiphobicity and antibacterial property were prepared by surface modification of nanofibers of the cellulose substance (e.g., commercial filter paper). The filter paper was firstly etched by alkaline solution, and then uniform titania ultrathin film was deposited onto the nano fiber surfaces of the etched filter paper by a facial surface sol-gel process. Finally, the1H,1H,2H,2H-perfluorooctyl trimethoxysilane (PFOTMS) monolayer was self-assembled onto the titania ultrathin film pre-coated cellulose nanofiber surfaces. Relying on the rough morphology of the etched filter paper and the surface monolayer of PFOTMS with low surface energy, the inherent hydrophilic filter paper was converted into superhydrophobic material with high oleophobicity, as well as excellent antibacterial property.3. The fabrication of superhydrophobic material based on based on the natural cellulose substance. A superhydrophobic cellulose material was prepared by deposition of titania gel layer on the nanofiber surfaces of the cellulose substance with a facial surface sol-gel process, then CaCO3Crystal nucleus was deposited onto the titania gel layer pre-coated filter paper. Subsequently, the sample was immerged in geothermal water for CaCO3crystal growth; finally sodium stearate monolayer was self-assembled onto the sample surface. The obtained tiania/CaCO3/sodium stearate cellulose hybrid material shows the surperhydrophobic property. The facial and low cost crystallization method in fabrication of superhydrophobic materials extends the method in transform of surface wettability of the cellulose material.