二元脂肪酸对十六烷基三甲基溴化铵胶束化行为的影响

Effects of aliphatic dibasic acids on the micellization behavior of cetyltrimethylammonium bromide

利用表面张力法研究了不同温度下草酸、丙二酸、丁二酸、己二酸和辛二酸对十六烷基三甲基溴化铵(CTAB)胶束化行为的影响,并计算了胶束形成的热力学函数,讨论了焓-熵补偿现象。实验结果表明,上述脂肪酸均能够促进CTAB胶束的形成,随着2个羧基间烷基链长度的变化,使CTAB的临界胶束浓度下降的能力由强到弱的顺序是辛二酸、草酸、己二酸、丁二酸和丙二酸,温度升高有利于CTAB在二元脂肪酸溶液中的胶束形成,胶束化是自发的,主要驱动来自熵;胶束化存在焓-熵补偿现象,补偿温度T c=(301±2)K。

Effects of aliphatic dibasic acids, including oxalic acid, malonic acid, succinic acid, adipic acid and suberie acid on the mieellization behavior of cetyhrimethylammonium bromide （CTAB） were investigated using surface tension measurement at different temperatures. Thermodynamic parameters of the micellization process were calculated and enthalpy - entropy eolnpensation phenomenon was discussed. Experimental results showed that all of the above mentioned acids can promote the mieellization of CTAB. Following the change of length of the alkyl chains between the two earboxyl groups in the above mentioned acids, their capacity tor declining critical micelle concentration of CTAB will be reduced with a sequence of order as suberic acid 〉 oxalic acid 〉 adipic acid 〉 succinie acid 〉 malonic acid. Rising of temperature is favorable for the formation of micelles of CTAB. The micellizati0n process of CTAB is carried out spontaneously and is mainly entropy - driven. Enthalpy-entropy compensation phenomenon exists in the micellization process, and the compensation temperature （Tc） is （301±2） K.