十二烷基硫酸钠浓溶液的胶束行为与其溶液体相行为间的相关性

Correlation between Micellization and Bulk Phase Behavior of Concentrated Sodium Dodecyl Sulfate Solution

研究了十二烷基硫酸钠（SDS）浓溶液与／不与无机电解质氯化钠共存时的溶液胶束行为。通过表面张力、稳态荧光猝灭、超滤以及粘度测量等探讨了该胶束行为与其粘度间的相关性。实验条件下，不同浓度的十二烷基硫酸钠（SDS）浓溶液与／不与氯化钠共存时，对应于不同SDS浓度区域和相应的不同胶束形状时，胶束聚集数Nm、溶液本体的平衡单体浓度cUF及粘度η三者间有明显的相关性。Nm、cUF及η呈现出随浓度增加而增大的趋势。在无盐体系中，当SDS浓度低于15～17倍临界胶束浓度（cmc）时，相应的胶束构型为球状：约17倍和46倍cmc后，Nm陡升，相应的胶束构型分别由球状而棒状而后六角棒状。60倍cmc后，胶束进入层状结构。在含有质量分数为2％NaCl的体系中．观察到了更多的对应于不同胶束形状的胶束聚集数变化阶段．前期的变化趋势与无盐状态相一致；但当SDS浓度约为370倍cmc后，此时SDS达到了饱和溶解度并发生分相。在一种胶束形成并达到平衡的前半阶段，粘度随SDS浓度的增加而增大；而当胶束从一种形状向另一种形状的转变过程中，粘度随SDS浓度的增加而下降。

The micellization behavior of sodium dodecyl sulfate （SDS） in the presence/absence of NaCl was investigated. The correlations between the micelle aggregation number （Nm ） , the viscosity （η） , and equili- brium concentration of SDS monomer（cUF） in the solution were studied by means of surface tension determination, steady-state fluorescence quenching, ultra-filtration, and viscosity analysis. It was found that Nm, η and cUF increased with the increase of the SDS concentration, and η increased first during the micelle formation and earlier equilibrium phases, but subsequently decreased in the transition phases when micelle shape was changing. The micelle were sphere, rod, hexagonal phase and lamellar when the SDS concentration was 15 -17 times lower than that of cmc, 17 times lower than that of cmc, 46 times lower than that of cmc, and 60 times higher than that of cmc, respectively, in the absence of NaCl. More micelle transitions were observed in the presence of 2% NaCl, and the transition trend was the same as that in the absence of NaCl when the SDS concentration was 370 times lower than that of cmc, after which the phase separation occurred because SDS was saturated.