两种Gemini表面活性剂在气／液界面的混合单分子膜

用Langmuir膜天平测定了双头基四疏水链的季铵盐Gemini表面活性剂2C12-8-2C12·2Br和羧酸型Gemini表面活性剂c11pPHCOOH在气／液界面的表面压(π)-每个分子平均占据面积(A)的等温线,考察了压缩模量(ε)、过剩面积(△AE)、过剩自由能(△GE)等热力学参数随混合体系组成的变化。结果表明,纯组分体系和混合体系均形成液相扩展态单分子膜,混合体系的组成显著影响气／液单分子膜的性质以及组成膜的分子之间的相互作用。

Mixed Monolayer of Two Gemini Surfactants at the Air/Water Interface

The mixed monolayer at the air/water interface of two Gemini surfactants C11pHCOOH and 2C12-8-2C12·2Br mixture was studied using Langmuir balance technique. The surface pressure -area (π-A) isotherms of the mixed monolayer as well as the change of the compression modulus (ω) , the excess area (△AE) and the excess energy (△GE) with the mole fraction of C11pHCOOH in the mixed system were investigated. The results showed that the films formed with either the individual Gemini surfactants or their mixture displayed a character of liquid-expansion. The composition of the mixed monolayer affected significantly the properties of the film as well as the interaction between molecules in the mixed monolayer.