氨基酸型表面活性剂烷基二羧酸钠的结构对表面活性、自聚集行为及润湿性能的影响

The Effect of the Structures of Dicarboxylic Amino Acid-based Surfactants on the Surface and Wetting Properties and Aggregation Behavior

本文合成了3个氨基酸型表面活性剂:十二烷基甘氨酸钠(C12GlyNa)、十二烷基氨基丙二酸钠(C12MalNa2)和十二烷基谷氨酸钠(C12GluNa2),用表面张力法、荧光探针法及接触角测量,研究了它们的分子结构对表面活性、自聚集行为以及对方解石润湿性能的影响。结果表明,当增加一个羧基后,氨基酸型表面活性剂的临界胶团浓度(cmc)和最低表面张力(γ_(cmc))增大,饱和吸附量(Г_(max))和胶团聚集数减小,降低表面张力的效率(pC_(20))降低,但在方解石表面的接触角变化较小。与C12MalNa2相比,在两个羧基之间增加一个亚甲基的C12GluNa2,其最低表面张力(γ_(cmc))变化很小,但cmc和Г_(max)更小,A_(min)更大,在方解石表面的最大接触角增大,对方解石的润湿性能降低。

Three amino acid-based surfactants,C12 GlyNa,C12 MalNa2,C12 GluNa2,were prepared and their structures were identified by 1 HNMR.Their surface properties and aggregation behavior were studied.Compared to C12 GlyNa,C12 MalNa2 shows higher values of cmc,γcmcand lower values ofГmaxand pC20.The surfactant,C12 GluNa2,exhibits lowerГmaxand higher Amin compared to C12 MalNa2.The maximum contact angle of C12 GluNa2 solution on the calcite surface is higher than that of C12 MalNa2 solution.The methylene group between two carboxyl groups shows great influences on the surface properties and the aggregation behavior.