阴/阳离子表面活性剂复配体系的物化性能——不同乙氧基化数对溶解性及表面张力的影响

Physical chemical properties of anionic and cationic surfactant blend ——Effect of different oxyethylene units on solubility and surface tension

研究了十二烷基甲基聚氧乙烯氯化铵与脂肪醇聚氧乙烯醚硫酸盐复配体系在不同乙氧基化数的溶解性、表面张力及临界胶束浓度。复配体系的溶解性随乙氧基化数的增加而增加,乙氧基化数为2的阳离子与乙氧基化数为2、3的阴离子复配,在较大的浓度范围内可以在水中形成透明的均匀溶液;乙氧基化数为5的阳离子与乙氧基化数为2、3的阴离子复配,在活性物质量分数为25%以下时完全透明。复配体系的临界胶束浓度(cmc)及其表面张力(γcmc)较单一组分低得多,且表面活性随乙氧基化数增加而下降。未经提纯的阴、阳离子表面活性剂,复配后其γ-c曲线中最低值现象明显减弱至消失。

The solubility,surface tension and critical micelle concentration of the anionic and cationic surfactant blend of dodecyl polyoxyethylene methylammonium chloride and dodecyl polyoxyethylene ether sulfate with different oxyethylene units were studied.The results showed that the systems become more soluble with the increase of oxyethylene units in the surfactants.The aqueous solution of the blend is homogeneous and transparent with a wide range of concentration of the blend of cationic surfactant with 2 oxyethylene units and anionic surfactant with 2 or 3 oxyethylene units,and the aqueous solution of blend surfactant with concentration below 25 %(mass)in which the cationic surfactant consists of 5 oxyethylene units and the anionic surfactant consists of 2 or 3 oxyethylene units are complete transparent.The cmc and γ_(cmc) of the blend are much lower than that of the single surfactant system,and decrease with the increase of oxyethylene units in the surfactants.In case the blend surfactant is not purified,the lowest value of surface tension in the γ-c curve is not clear and disappears gradually.