Humphry-Baker Robin, Grätzel Michael, Moroi Yoshikiyo
Institute de Chimie Physique II, Ecole Polytecnique Federal de Lausanne, CH-1015 Lausanne, Switzerland.
Langmuir. 2006 Dec 19;22(26):11205-7. doi: 10.1021/la062014+.
The dependence of pyrene fluorescence spectra on the concentration of sodium dodecyl sulfate (SDS) was observed, where the solution was prepared from water saturated with pyrene. The values of the I(1)/I(3) ratio from the bulk solution and from the upper meniscus region in an optical cell were similar but decreased rapidly around the critical micelle concentration (cmc) of SDS, indicating that pyrene molecules preferred to be solubilized in the micelles having a lower dielectric constant. The fluorescence intensity of the excimer indicated the concentration of pyrene molecules at the air/solution interface or the surface activity of pyrene molecules. In addition, the intensity from the meniscus region is much larger than that from the bulk at the concentrations below the cmc, whereas there was no difference in the intensity between the bulk and the meniscus above 8 mmol dm(-3) of SDS. The analysis of the fluorescence intensity from the excimer strongly suggests the presence of molecular aggregates that are favorable to the pyrene molecules just like the micelles in the bulk, making them less movable.
观察到芘荧光光谱对十二烷基硫酸钠（SDS）浓度的依赖性，其中溶液由芘饱和的水制备。光学池中本体溶液和上弯月面区域的I(1)/I(3)比值相似，但在SDS的临界胶束浓度（cmc）附近迅速下降，这表明芘分子更倾向于溶解在介电常数较低的胶束中。激基缔合物的荧光强度表明了芘分子在空气/溶液界面的浓度或芘分子的表面活性。此外，在低于cmc的浓度下，弯月面区域的强度远大于本体的强度，而在SDS浓度高于8 mmol dm(-3)时，本体和弯月面之间的强度没有差异。对激基缔合物荧光强度的分析有力地表明，存在着与本体中的胶束类似的、有利于芘分子的分子聚集体，使它们的移动性降低。
