The physicochemical properties of a cationic α,ω-type(bolaform) surfactant, eicosane-1,20-bis(trimethylammonium) dibromide (C20Me6), were investigated by means of surface tension, electrical conductivity, density, dye solubilization, fluorescence, and light scattering. The results obtained for C20Me6 were compared with those for decyltrimethylammonium bromide (C10Me3). The surface tension measurement suggests that C20Me6 has a folded, “wicket-like” conformation at the air–water interface. The cmc of C20Me6 was smaller than that of C10Me3. The apparent ionization degree of C20Me6 was larger, and the polarity of the micellar Stern layer was higher than that of C10Me3. It was found that the C20Me6 micelle has an aggregation number of about 19, a hydrodynamic radius of 16 Å, and a partial molar volume of 480.49×10−3 dm3 mol−1, suggesting that the micelle is nearly spherical; thus, the main alkyl chain is almost stretched, and the outermost region of the micelle is loose.
                                    通过表面张力、电导率、密度、
染料增溶、荧光和
化学性质等研究了阳离子 α,ω 型(bolaform)表面活性剂
二十烷-1,20-二(三甲基
铵)二
溴化物(C20Me6)的理化性质。光散射。将 C20Me6 获得的结果与癸基三甲基
溴化铵 (C10Me3) 的结果进行比较。表面张力测量表明,C20Me6 在空气-
水界面处具有折叠的“小门状”构象。 C20Me6 的 cmc 小于 C10Me3 的 cmc。 C20Me6的表观电离度较大,胶束Stern层的极性高于C10Me3。结果发现,C20Me6胶束的聚集数约为19,流体动力学半径为16 Å,偏摩尔体积为480.49×10−3 dm3 mol−1,表明胶束接近球形;因此,主烷基链几乎被拉伸,并且胶束的最外层区域是松散的。