Department of Physical Chemistry, University of Lodz, 90-236 Lodz, Poland.
Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980 Dubna, Russia.
Int J Mol Sci. 2020 Aug 13;21(16):5828. doi: 10.3390/ijms21165828.
Inspired by the unusual shapes of the titration curve observed for many surfactants and mixed colloidal systems, we decided to extend the analysis to isothermal titration calorimetric curves (ITC) by paying special attention to potential structural changes in micellar aggregates. In this paper, we used isothermal titration calorimetry in conjunction with Scanning Transmission Electron Microscopy (STEM), Small-Angle Neutron Scattering (SANS) and X-ray Scattering (SAXS) methods support by Monte Carlo and semiempirical quantum chemistry simulations to confirm if the isothermal calorimetric curve shape can reflect micelle transition phenomena. For that purpose, we analysed, from the thermodynamic point of view, a group of cationic gemini surfactants, alkanediyl-α,ω-bis(dimethylalkylammonium) bromides. We proposed the shape of aggregates created by surfactant molecules in aqueous solutions and changes thereof within a wide temperature range. The results provide evidence for the reorganization processes and the relationship (dependence) between the morphology of the created aggregates and the conditions such as temperature, surfactant concentration and spacer chain length which affect the processes.
受许多表面活性剂和混合胶体系统观察到的滴定曲线的异常形状的启发，我们决定通过特别关注胶束聚集物中潜在的结构变化，将分析扩展到等温热滴定曲线（ITC）。在本文中，我们使用等温滴定量热法结合扫描透射电子显微镜（STEM）、小角中子散射（SANS）和 X 射线散射（SAXS）方法，并辅以蒙特卡罗和半经验量子化学模拟，以确认等温量热曲线的形状是否可以反映胶束转变现象。为此，我们从热力学的角度分析了一组阳离子双子表面活性剂，即二烷基亚，ω-双（二甲基烷基）溴化铵。我们提出了在水溶液中由表面活性剂分子形成的聚集体的形状及其在较宽温度范围内的变化。结果为重组过程提供了证据，以及所创建的聚集体的形态与温度、表面活性剂浓度和间隔链长度等影响过程的条件之间的关系（依赖性）。
