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Study On Sol-gel Preparation And Properties Of Nano-porous Silica Optical Coatings

Posted on:2018-11-15Degree:MasterType:Thesis
Country:ChinaCandidate:Y XiaoFull Text:PDF
GTID:2321330518487638Subject:Materials Science and Engineering
Abstract/Summary:PDF Full Text Request
Among various optical filters, Anti-reflection (AR) coating can suppress the reflection of light on the surfaces or interfaces of transparent substrates and improve optical properties (transparency and visibility). In particular, for solar systems, it is able to improve the efficiency of solar power generation by increasing the absorption of certain spectral response ranges in solar collectors. In addition, many applications require an increase in the transmittance in the front surface reflection of transparent materials.Using sol-gel method to preparing porous AR coating have attracted so many attentions from researchers around the world, but how to control the stability of coating sol and improve the mechanical properties of AR films is the key for scale-up application. In this thesis, based on template and sol-gel method, high performance hierarchical nanoporous AR films were made by facile dip coating cooperating with hollow silica nanospheres and block copolymer F127 as pore maker. For scale-up application, using emulsion polymerization and sol gel method to produce organic-inorganic composite sol with high solid concentration. The microstructure and optical properties of the prepared porous silica nanospheres and films were characterized by Transmission electron microscope(TEM), Fourier transform infrared spectroscopy (FT-IR) spectra, UV-visible spectrophotometer (UV-VIS) and scanning electron microscopy(SEM) and so on.Preparation study shows that surface modification can suppress the aggregation of nanospheres, and the sol show better stability when combined the steric effect caused by special silane coupling agents. The optical characterization illustrate that it improved the transmittance of the films with an optimized maximum transmittance of 98.21% in the visible spectral region. The nano-scale surface embossments due to the addition of HSNs was also contributory to the AR effect of the films, especially at 45° and 5°incident angle. In the same time, the composite sol was mixed with different binder sol such as silica alumina, titanium sol. Among these films, the silica sol and alumina sol have a great contribution to the improvement for transmittance of bare glass and it have huge potential to be applied to solar glass cover pane.
Keywords/Search Tags:antireflective film, porous silica, Nano hollow sphere, surface modification, sol-gel method, template method, emulsion polymerization, stable sol
PDF Full Text Request
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