振动光谱法研究水溶液中十六烷基三甲基溴化铵的分子构象

ON THE MOLECULAR CONFORMATIONS OF CETYLTRIMETHYLAMMONIUM BROMIDE IN AQUEOUS SOLUTION BY VIBRATIONAL SPECTROMETRY

研究长链分子在水溶液中的分子构型有助于更好地理解生物膜的结构及生物大分子链(如蛋白链)的结构,受到人们的高度重视。许多表面活性剂分子的结构和性质已用各种物理和化学方法广泛地研究过,但用振动光谱方法(尤其是红外光谱法)研究水溶液中表面活性剂分子构象的报道则很少。十六烷基三甲基溴化铵(CTMAB)是一种典型的阳离子型表面活性剂,我们曾讨论了温度对CTMAB分子链亚晶胞堆积形式的影响。

The Raman and FT-IR spectra of a 30% aqueous solution of cetyltrimethylammonium bromide have been investigated. A transition from coagel to micelle phase was observed at 300K. In the coagel phase, the hydrocarbon molecules exist in the bent end-methyl TG conformation with a few kink GTG forms. In the micellar phase, the number of GTG conformers increases, and the gauchetrans-ganche(GTG) and the doublegauche (CG) conformers exist in considerable concentrations.