作　　者： (王钰熙）; (林珂）; (陈琳）; (周晓国）; (刘世林）;

机构地区： 中国科学技术大学化学物理系,合肥微尺度物质科学国家实验室（筹）,合肥230026

出　　处： 《Chinese Journal of Chemical Physics》 2017年第4期365-371,I0001,共8页

摘　　要： 本文利用拉曼光谱的垂直偏振谱提高了SDS水溶液中CH段光谱探测灵敏度，光谱结果给出了SDS在H2O中的第一临界胶束浓度和第二临界胶束浓度分别为8．5和69mmol／L，这与表面张力测量的结果一致．因为垂直偏振拉曼光谱的高灵敏度，可以给出较大浓度盐溶液中SDS的临界胶束浓度值．在100mmol／L的NaCl／H2O溶液中这两个临界胶束浓度分别为1．8和16．5mmol／L．根据SDS在水和NaCl水溶液中的拉曼光谱及表面张力数据，讨论了SDS在体相和界面完整的自组装过程．更重要的是讨论了盐离子、SDS分子和水分子之间的相互作用力．这些研究表明垂直偏振拉曼光谱在研究自组装过程中有着重要作用． Molecular self-assembly is extremely important in many fields, but the characterization of their corresponding intermolecular interactions is still lacking. The C-H stretching Raman band can reflect the hydrophobic interactions during the self-assembly process of sodium dodecyl sulfate （SDS） in aqueous solutions. However, the Raman spectra in this region are seriously overlapped by the OH stretching band of water. In this work, vertically polarized Raman spectra were used to improve the detection sensitivity of spectra of C-H region for the first time. The spectral results showed that the first critical micelle concentration and the second critical micelle concentration of SDS in water were 8.5 and 69 mmol/L, respectively, which were consistent with the results given by surface tension measurements. Because of the high sensitivity of vertically polarized Raman spectra, the critical micelle concentration of SDS in a relatively high concentration of salt solution could be obtained in our experiment. The two critical concentrations of SDS in 100 mmol/L NaCl solution were recorded to be 1.8 and 16.5 mmol/L, respectively. Through comparing the spectra and surface tension of SDS in water and in NaCl solution, the self-assembly process in bulk phase and at interface were discussed. The interactions among salt ions, SDS and water molecules were also analyzed. These results demonstrated the vertically polarized Raman spectra could be employed to study the self-assembly process of SDS in water.

关 键 词： 垂直偏振拉曼光谱 十二烷基硫酸钠 自组装 临界胶束浓度 分子间相互作用力