十二烷基甜菜碱/十二烷基硫酸钠复配体系的表面活性

研究了两性表面活性剂十二烷基甜菜碱（C12BE）和阴离子型表面活性剂十二烷基硫酸钠（SDS）复配体系的形成胶束能力，降低表面张力效率，降低表面张力能力三种增效作用.发现C12BE和SDS摩尔比为6 :4时增效作用最显著.并考察了盐、醇对复配体系表面活性的影响，结果表明，加盐能导致表面活性的提高，加醇的机理比较复杂，乙醇对复配体系表面活性影响不大，而正丁醇影响则比较显著.

Surface Activity of Mixed System of Dodecyl Betaine and Sodium Dodecyl Sulphate

The ability of forming micell, the effciency and the ability of reducing surface tension by the in- teraction of zwitterionic and anionic surfactants (C12H25N (CH3)2 CH2COO-/C12H25SO4Na) has been investi- gated. It is found that when the molar fraction of C12BE is about 0.6, the surface activity shows a maximum. The influence of NaCl and alcohols on surface properties of the mixed system has also been studied. The surface activity is enhanced and the cmc value of C12BE/SDS system is reduced with the increase of NaCl concentration, because sodium ions induce a decrease of electrostatic repulsion between hydrophilic groups in surfactant molecules. The effect is more complex with the addition of alcohols, the surface activity improves with in- creasing the volume fraction of n-butanol. But no remarkble influence on surface activity has been observed for alcohols of short chain, for example ethanol.