Chemical Laboratory, Physical and Inorganic Chemistry Division, Central Leather Research Institute, Council of Scientific and Industrial Research, Sardar Patel Road, Adyar, Chennai 600020, Tamil Nadu, India.
Colloids Surf B Biointerfaces. 2011 Jan 1;82(1):126-33. doi: 10.1016/j.colsurfb.2010.08.028. Epub 2010 Sep 20.
In the present paper, we report the micellization, aggregation behavior and thermodynamics of a cationic surfactant viz. cetyltrimethylammonium bromide (CTAB) in absence and presence of tyrosine-hydantoin (TH) drug. The solution behavior of the mixture of CTAB and TH drug has been determined using conductivity, surface tension, UV-visible and fluorescence spectroscopic methods. A strong interaction between the two amphiphiles is indicated from the above measurements. The critical micelle concentration (cmc) of CTAB is found to decrease with increase in the amount of TH in the mixture. The cmc values obtained by these methods are in good agreement with each other. The critical micelle concentration, aggregation number and standard free energy changes of aggregation of the surfactant (CTAB) in aqueous solution in absence and presence of TH are evaluated at different temperatures (294, 303 and 318K). The aggregation number is obtained by the steady-state fluorescence spectroscopic method. Thermodynamic parameters (the standard Gibbs energy change of micellization, ΔG°(m), the standard enthalpy change of micellization, ΔH°(m), the standard entropy change of micellization, ΔS°(m), the standard Gibbs (transfer) energy, (ΔG°(m))(tr)' , and the excess free energy change of micellization, ΔG(ex)) have been evaluated. The negative values of standard Gibbs energy change indicate spontaneous micellization and synergism. The interaction parameter, β(m), activity coefficients (f(1), f(2)) have been evaluated, and using these data we evaluated excess Gibbs energies, which indicate the spontaneity and the stability of the mixed micelles.
在本文中，我们报告了阳离子表面活性剂十六烷基三甲基溴化铵（CTAB）在不存在和存在酪氨酸-海因（TH）药物时的胶束化、聚集行为和热力学。使用电导率、表面张力、紫外-可见和荧光光谱法测定了 CTAB 和 TH 药物混合物的溶液行为。从上述测量结果表明，两种两亲物之间存在强烈相互作用。CTAB 的临界胶束浓度（cmc）随着混合物中 TH 量的增加而降低。这些方法得到的 cmc 值彼此吻合良好。在不同温度（294、303 和 318K）下，评估了 CTAB 在水溶液中不存在和存在 TH 时的临界胶束浓度、聚集数和标准自由能变化。通过稳态荧光光谱法获得聚集数。热力学参数（胶束化的标准吉布斯自由能变化，ΔG°(m)、胶束化的标准焓变，ΔH°(m)、胶束化的标准熵变，ΔS°(m)、标准吉布斯（转移）能，（ΔG°(m))(tr)'和胶束化的超额自由能变化，ΔG(ex)）进行了评估。标准吉布斯自由能变化的负值表明自发胶束化和协同作用。相互作用参数，β(m)、活度系数（f(1)、f(2)）进行了评估，并利用这些数据我们评估了超额吉布斯能，这表明了混合胶束的自发性和稳定性。
