CTAB反相微乳液中水和辛烷分子的自扩散研究  

Self- Diffusion Study of Solvent Molecules in CTAB Inverse Microemulsion

作　　者：徐健[1] 李干佐[1] 周国伟[1] 陈文君[1] 姚发业[1] 

机构地区：[1]山东大学

出　　处：《化学学报》2001年第5期707-712,共6页Acta Chimica Sinica

基　　金：国家自然科学基金

摘　　要：利用电导测量确定了CTAB/正丁醇/正辛烷/水四组分体系的相态,在反相微乳液区有明显的渗滤现象,通过脉冲梯度场核磁共振方法研究了反相微乳液中水和辛烷分子的自扩散行为,采用双指数拟合得出辛烷的自扩散系数.对于体系中出现的渗滤现象以及水和辛烷分子自扩散系数反常的原因,从分子水平上进行了解释.水的自扩散系数(2～7×10-10 m@s-1)比一般文献值高,其原因:一是水在油相中有较大的溶解度;二是渗滤现象的存在,由于液滴间相互作用的增强和'粘性”碰撞而导致液滴的融合,以及由此而形成的瞬时水相连续通道,使水的自扩散系数增大.而辛烷自扩散系数比一般文献值小,则是由于在微乳液液滴的栅栏层中表面活性剂分子烃链与辛烷分子间范德华引力所造成.Quaternary inverse microemulsion of a cationic surfactant (cetyltrimethylammonium bromide, CTAB), octane, water, and 1-butanol has been investigated by using conductivity, pulsed field gradient spin-echo NMR measurements. The conductivity behavior of such microemulsions has a distinct percolative phenomenon. in the W/ O microemulsion region, the self - diffusion coefficient of water is relatively high ( 2 similar to 7 x 10(-10) m .s(-1)) due to their higher solubility of water in the continuous phase, which is composed of octane (w = 10%) and 1-butanol tan apolar solvent and a weak polar solvent), and 'sticky' collisions between the droplets in the percolation range. Penetration of a large amount of octane molecules between surfactant chains significantly lowers (1 similar to 3 x 10(-10) m(2).s(-1)) the self-diffusion coefficient of octane.

关 键 词：核磁共振 反相微乳液 电导 渗滤现象 自扩散系数 十六烷基三甲基溴化铵 水 正辛烷 正丁醇 

分 类 号：O648.23[理学—物理化学]