聚乙二醇在气液界面上的特性标度指数

Characteristic Scaling Exponent (ν) of Polyethylenglycol(PEG) at the Air-aqueous Solution Interface

通过分析气/液界面上聚乙二醇(PEG)铺展膜的表面压等温曲线(Π/Γs曲线),讨论和比较氯化钠和二甲基乙酰胺亚相溶液对PEG气/液界面膜及PEG的特性标度指数(ν)的影响。结果表明与氯化钠亚相溶液的情况相反,0.10mol/L二甲基乙酰胺亚相溶液使聚乙二醇单分子膜的平衡表面压由8.1mN·m-1降低至4.6mN·m-1,气液界面上PEG的单元链节极限面积由3.46nm2增加至38.1nm2,由表面压和表面浓度的双对数曲线得到ν值从0.75增加至0.81。这些结果表明气液界面上PEG单分子膜的性质及其值显示出对亚相溶液性质有明显依赖性,反映出了PEG与亚相溶液相互作用的热力学变化。

This work aimed to investigate the effect of dimethylacetamide subphase on the polyethylene glycol (PEG) monolayer at air-aqueous solution and its values through the analysis of PEG surface pressure isotherms (curves). The results showed that at 0.10 mol/L dimethylacetamide air aqueous solution interface, the PEG monolayer surface pressure lowed from 8.1 mN&middotm-1 to 4.6 mN&middotm-1, the area per monomer of PEG increased from 3.46 nm2 to 38.1 nm2, and the v values of PEG increased from 0.75 to 0.81. The data indicated a marked dependence on the nature of the subphase sad reflected the change in the thermodynamics of the interaction between PEG and the subphase.