排序方式: 共有2条查询结果,搜索用时 0 毫秒
1
1.
Perullini Mercedes Jobbágy Matías Bilmes Sara A. Torriani Iris L. Candal Roberto 《Journal of Sol-Gel Science and Technology》2011,59(1):174-180
Silica matrices synthesized from a pre-hydrolysis step in ethanol followed by alcohol removal at low pressure distillation,
and condensation in water, are suitable for encapsulation of biomolecules and microorganisms and building bioactive materials
with optimized optical properties. Here we analyze the microstructure of these hydrogels from the dependence of I(q) data acquired from SAXS experiments over a wide range of silica concentration and pH employed in the condensation step. From
the resulting data it is shown that there is a clear correlation between the microscopic parameters—cluster fractal dimension
(D), elementary particle radius (a) and cluster gyration radius (R)—with the attenuation of visible light when the condensation step proceeds at pH < 6. At higher pHs, there is a steep dependence
of the cluster density (~R
D−3) with the condensation pH, and non-monotonous changes of attenuance are less than 20%, revealing the complexity of the system.
These results, which were obtained for a wide pH and silica concentration range, reinforce the idea that the behavior of gels
determined in a restricted interval of synthesis variables cannot be extrapolated, and comparison of gelation times is not
enough for predicting their properties. 相似文献
2.
1