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The kinetic of the sol–gel hydrolysis and polycondensation reactions of a chiral ORMOSIL precursor was investigated by LCMS
technique as a function of water excess and pH. While the amount of water does not significantly change the kinetics, the
reactions strongly depend on the [H]+ concentration. At pH ≤ 3, the hydrolysis is very fast and the conversion of the precursor is completed within less than 1
h whereas at 80% of the precursor is still present after 50 h at pH = 3.5. This kinetic study allows to define a set of initial
conditions and time ranges required to provide good optical quality dip coated films .
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L. GuyEmail: |
2.
The aerosol-gel process is a thin film deposition process based on the sol-gel polymerisation of a liquid film deposited from
an ultrasonically sprayed aerosol. This process offers an attractive alternative for the deposition of sol-gel thin films.
The effects of the aerosol deposition route on the film characteristics have been investigated with regard to sol-gel chemistry.
TEOS solutions have been studied by viscosimetry and FTIR spectroscopy using an ATR device. Silica xerogel coatings have been
studied by transmission FTIR and optical microscopy. Film morphology and uniformity depend closely on the aerosol deposition
conditions. The film growth is controlled by a droplet coalescence surface phenomenon. 相似文献
3.
We report on the interplay between experimental arrangement, resonant radiation trapping and decay measurements of infra-red emission of erbium doped glasses. The impact of the relative position between the exciting and detecting positions of the bulk samples is investigated. We show that the radiation trapping leads to long rise time dynamics evenly distributed outside the pulsed pumped region. 相似文献
4.
The aerosol-gel process is a thin film deposition technique based on the sol-gel polymerization of a liquid film deposited from an ultrasonically sprayed aerosol. SiO2 layers have been deposited by aerosol-gel process from TEOS solutions prepared using a two-step procedure. After a post-treatment at 80°C, the layers have a remarkable abrasion resistance and a high refractive index. In this paper, the chemical mechanisms involved in the formation of SiO2 layers at low temperature are studied by FTIR spectroscopy and related to the processing conditions. 相似文献
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