阳离子表面活性剂三甲基溴化铵与硝酸铵相互作用的表面和热力学研究

本文系统研究了阳离子表面活性剂三甲基溴化铵和硝酸铵盐的表面现象和自聚集行为. 采用电导法和表面张力法研究在不同温度下阳离子表面活性剂三甲基溴化铵的表面性质和热力学性质. 通过表面张力测定得到临界胶束浓度、吸附自由能、胶束化的自由能、最小分子面积和表面过量浓度. 该研究表明，胶束化过程是自发放热反应. 电导测定结果确定了临界胶束浓度、电离程度和反离子结合度. 加入硝酸铵盐至表面活性剂溶液后，临界胶束浓度降低，电离程度和反离子结合度增加，更加有利于胶束化过程的自发. 该研究对进一步理解电解质和表面活性剂之间相互作用具有重要意义.

Interactions of Cationic Surfactant Cetyl-trimethyl ammonium bromide with Ammonium nitrate: Surface and Thermodynamic Studies

The study of interactions between surfactant and salt in aqueous solutions has attracted significant interest in recent years because of their widespread applications and relatively complex behavior. This work reports the systematic study of surface phenomenon and self-aggregation behavior of cationic surfactant cetyltrimethyl ammonium bromide (CTAB) with ammonium nitrate (NH₄NO₃) salt. Surface and thermodynamic properties of cationic surfactant CTAB with NH₄NO₃ were investigated at different temperatures using different techniques such as conductometry and surface tensiometery. The surface tension measurement was carried out to find out the critical micelle concentration, free energy of adsorption, free energy of micellization, minimum area per molecule, and surface excess concentration. The study reveals that the process of micellization is spontaneous and exothermic in nature. Conductance measurement was carried out to determine critical micelle concentration, degree of ionization and degree of counter ion binding. Addition of NH₄NO₃ to the surfactant solutions increase the values of degree of ionization and degree of counter ion binding, although it lowers the values of critical micelle concentration showing that the process of micellization is more favorable and spontaneous. The study is very helpful to develop better understanding about interaction between electrolyte and surfactant, which are used in many applications and in different processes (e.g., pharmaceutical, industrial foaming, drug solubilization, oil recovery, and medium for metal nanoparticle formation).