辛烷基苯酚聚氧乙烯醚与正癸醇层状液晶的有序性及层状结构

Order Character and Lamellar Structure of TritonX-100/n-C_(10)H_(21)OH/H_2O Lamellar Liquid Crystal

研究了层状液晶的层状结构及有序性,用偏振光显微镜法确定了辛烷基苯酚聚氧乙烯醚(TritonX 100)与正癸醇体系25℃时层状液晶的区域,绘制了部分相图,并用核磁共振氢谱法(2H NMR)进一步验证;用自旋标记电子自旋共振法测定了层状液晶分子排列的有序参数,研究结果显示,不同组分TritonX 100 /n C10H21OH/H2O体系层状液晶的超精细偶合常数基本相同,表明层状液晶中的微极性是一致的.而有序参数随着TritonX 100含量的增加而增加,随着层状液晶中水含量的增加而减少;用小角度X射线衍射方法测定了层状液晶的层间距离,并计算了水分子在层状液晶中的渗透率,其渗透率约为50%.

Order character and lamellar structure of TritonX-100/n-C_10 H_ 21 OH/H_2O lamellar liquid crystal were investigated. Partial phase diagram of TritonX-100/C_ 10 H_ 21 OH/H_2O was measured at 25℃ by the polarizing microscope, and lamellar structure of the lamellar liquid crystal was verified by the ~2H NMR spectra. The ESR spin probe method was used to detect the changes in the lamellar liquid crystal. A stearic acid, 5-doxylstearic acid, was used as the spin probe. The values of hyperfine coupling constant and order parameter of lamellar liquid crystal in the phase diagram were calculated. The values of the hyperfine coupling constant with different composition were almost unchanged. It indicates that the micropolarity of the lamellar liquid crystal is very similar. The order parameter decreases with the increasing water content in lamellar liquid crystal. It can be explained by considering that: First, though the penetration is determined at the given weight ratio of C_ 10 H_ 21 OH to TritonX-100, the absolute water content penetrated into the amphiphile bilayer increases with the increasing of the water content. Second, the thickness of the solvent also increases, which makes the force between layers weaker. The results also showed that order parameter of lamellar liquid crystal increased with TritonX-100 content, which may be explained from the fact that the water content penetrated into the amphiphile bilayer decreases relatively and the molecules in the amphiphile bilayer are made tighten. The interlayer spacing of lamellar liquid crystal was determined by small angle X-ray diffraction. The penetration ratio of water in the lamellar liquid crystal was calculated. It was about 50%.