气/液界面及固体表面硬脂酸LB膜结构性质研究

对气液/和固/液界面上硬脂酸LB膜的结构性质的研究表明,二价离子能够使气/液界面上LB膜表面压力降低,并出现一个固-固转变的过程.对此可以解释为是由二价离子富集在亚相表面,减弱了膜分子之间的库仑作用,使表面电势降低引起的.同时由于二价离子与硬脂酸分子形成复合物,单层膜的结构发生改变,导致固-固转变点的产生.对固体基质上多层LB膜的椭圆偏振研究表明,有序排列的硬脂酸LB膜具有明显的双折射性质.电镜观察发现两个固相垂直提位获得的多层膜在形貌上存在差异,低压固相膜较之高压固相膜存在明显的不均匀性.分析认为这是在膜从气/液界面向固体表面转移过程中发生重结晶引起的.

STUDY ON STEARIC ACID LB FILM ON AIR/WATER INTERFACE AND SOLID SUBSTRATE

The study of LB films is becoming increasingly important for its application in biology, material sciences and many other fields, especially in the field of biomembrane study. We studied LB film of steaic aicd on air/water interface and on solid substrate. The study shows that the addition of divalent ions not only decreases the transition pressure of stearic acid momolayer from liquid phase to solid phase, but also causes a solid-solid transition. This is due to the high concentration of divalent ions at the air-water interface and thus the reduction of Columb repulsion between the surface molecules. The ellpsometry study of cadmum stearate multilayers on silicon substrate indicates that this kind of films have anisotropic effect. From the electron microscopic observation we found that there is deferences of the surface topographies between the multilayers obtained from the two solid phase. This may be due to the recrystalliztion of LB films when they are transfered from air-water interface to solid substrate.