Obstructed Diffusion in Silica Colloidal Crystals
Obstructed Diffusion in Silica Colloidal Crystals
复制标题
DOI：
10.1021/jp400496p
复制
发表时间：
2013-07-25
影响因子：
2.9
通讯作者：
Wirth, Mary J.
中科院分区：
文献类型：
--
作者：
Rogers, Benjamin J.;Wirth, Mary J.
通过光漂白后的荧光恢复和离子电导率的测定，对二氧化硅胶体晶体中的扩散受阻现象进行了实验研究。粒径变化为120、220、470和1300 nm，孔隙率通过流动测量来确定。对于荧光素，实验结果表明，在实验误差范围内，阻碍因子即介质内扩散系数与开放溶液中的扩散系数之比等于孔隙度。对于蛋白质，在对孔的大小进行了排除后，得出了相同的结论。这些介质的阻碍系数比色谱介质低2倍，比理论预测高6096，等于随机纤维中电泳筛分的假设。
The hindered diffusion in silica colloidal crystals was studied experimentally, both by fluorescence recovery after photobleaching and by measurement of ionic conductivity. Particle size was varied to include 120, 220, 470, and 1300 nm, and the porosities were determined by flow measurements. For fluorescein, the results showed that the obstruction factor, which is the ratio of the diffusion coefficients inside the media and in open solution, is equal to the porosity within experimental error. For proteins, the same conclusion is made after correction for size exclusion of the pores. The obstruction factors for these media are 2-fold lower than those measured for chromatographic media, 6096 higher than theoretical predictions, and equal to what is assumed for electrophoretic sieving in random fibers.