阳离子表面活性剂在一水硬铝石表面吸附研究

Structure of the Adsorbed Layer of Cationic Surfactant at Diaspore-Water Interface

采用荧光探针法研究了在烷基伯胺和季铵盐阳离子表面活性剂在一水硬铝石表面吸附层结构.研究结果表明,低浓度且阳离子表面活性剂在一水硬铝石表面为静电吸附时,其表面微极性大,阳离子表面活性剂零星吸附于矿物表面.当阳离子表面活性剂浓度增加时,一水硬铝石表面的微极性降低,阳离子表面活性剂在一水硬铝石表面形成了胶束吸附,形成胶束的表面活性剂离子的数随其浓度的增加而增加,表面疏水性逐渐增强,直至完全疏水.随着烃链碳原子数的增加,阳离子表面活性剂在一水硬铝石表面形成胶束吸附的浓度降低.烷基伯胺为弱电解质,其在水溶液中同时存在烷基胺离子和分子,由于离子分子共同吸附,烷基伯胺比相同碳原子数的季铵盐在一水硬铝石表面形成的半胶束吸附的分子数多.

Pyrene fluorescence probe was used to investigate the structure of the adsorbed layer of cationic surfactants primary amines and quaternary amines at the diaspore-water interface. The cationic surfactants adsorb readily due to electrostatic interactions on diaspore surfaces in the lower surfactant concentration range. The macropolarity of diaspore surfaces is high, and the adsorbed layer formed in such a manner is sporadic. With an increase of surfactant concentration, the macropolarity of diaspore surface decreases above given concentration. It shows hemimicelle adsorption on the surface. With a further increase in surfactant concentration, the surfactant molecule number of forming hemimicelle on the diaspore surface increases until the surface completely hydrophobility. With an increase in the length of alkyl chains the concentration of surfactants decreases to form hemimicelle adsorption. The ionomolecular complexes exist in the primary amines solution and the primary amines adsorbed layer will be made up of bigger aggregate structure than quaternary amines.