title: [Preparation and infrared spectral analysis of nanoporous silica thin film].
abstract: Crack-free homogeneous nanoporous silica films on silicon wafer have been synthesized via supercritical drying of wet gel films obtained by spin-coating the polymeric silica sol, which was prepared using sol-gel method with tetraethoxysilane (TEOS) as precursor. The film is amorphous and nanoporous, and three-dimensional network, cross-linked by the primary particles whose sizes distribute between 10-20 nm showed respectively by XRD and SEM micrograph. The structure of the nanoporous SiO2 thin film was studied by FTIR spectra. The SiO2 thin film was composed of Si-O-Si and Si-OR, and was hydrophobic. The film contained Si-OH and became hydrophilic after being heat-treated at 250 degrees C or above in air. The heat-treated SiO2 thin film becomes hydrophobic by reacting with trimethylchlorosilane(TMCS). The TMCS-modified SiO2 thin film remains hydrophobic and can keep its nanoporous structure at a temperature lower than 450 degrees C in nitrogen.
authors.affiliation: Key Lab of Advanced Ceramic Fibers and Composites, College of Aerospace and Material Engineering, National University of Defense Technology, Changsha 410073, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Wang
authors.forename: Chang-rui
authors.initials: CR
authors.lastname: Zhang
authors.forename: Jian
authors.initials: J
authors.lastname: Feng
authors.forename: Da-xiang
authors.initials: DX
authors.lastname: Yang
mesh_terms: D006358:Hot Temperature; D057927:Hydrophobic and Hydrophilic Interactions; D008567:Membranes, Artificial; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D016062:Porosity; D012821:Silanes / Q000737:chemistry*; D012822:Silicon Dioxide / Q000032:analysis / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014297:Trimethylsilyl Compounds / Q000737:chemistry
chemical_list: D008567:Membranes, Artificial; D012821:Silanes; D014297:Trimethylsilyl Compounds; C040733:tetraethoxysilane; C039293:trimethylchlorosilane; D012822:Silicon Dioxide