水/AOT/正庚烷微乳体系中水结构的FT-IR研究

运用傅立叶变换红外光谱（ＦＴ－ＩＲ）对水／ＡＯＴ／正庚烷微乳体系中水的微结构进行了研究。结果表明，随着体系中加水量的增大，水分子Ｏ－Ｈ伸缩振动的红外光谱由３４９３ｃｍ＾－１向低频移动至３４１７ｃｍ＾－１，微乳体系中，水分子与ＡＯＴ分子的磺酸基作用的同时，与Ｎａ＾＋也有一定的作用，这两种离子对水分子Ｏ－Ｈ键的强度均有一定的影响，磺酸基的作用使水分子中Ｏ－Ｈ伸缩振动向高波数方向移动，而Ｎａ＾＋的作用与

FT-IR Study of Water Structure in Water/AOT/n-Heptane Microemulsion System

Microstructure of water in water/AOT/n-heptane microemulsion system has been studied using fourier transform infrared spectroscopy (FT-IR). Intensity and peak position of O-H stretching band of water in the system were found to change with water content Wo, i.e. the molar ratio of water to surfactant (H2O/AOT). Intensity of O-H stretching vibration in the range of 3050 and 3750 cm-1 increased with water content and the frequency was also found to vary from 3493 to 3417 cm-1 in the system with increasing Wo values (from 1 to 60). Four types of circumstance of water exist in the microemulsion system located around 3590±20 cm-1, 3520±10cm-1, 3465±10 cm-1 and 3270±20 cm-1 were estimated after O-H stretching bands were resolved by curve fitting. The stretching band of carboxide splitted into two peaks located at 1739±2cm-1and 1722±2 cm-1 and the intensity ratio Ir(I1739/I1722) decreased with water content. These variations are due to both the hydration of head-group and the different conformation in AOT molecule.