Honegger Philipp, Schmollngruber Michael, Steinhauser Othmar
University of Vienna, Faculty of Chemistry, Department of Computational Biological Chemistry, Währingerstr. 17, A-1090 Vienna, Austria.
Phys Chem Chem Phys. 2018 Apr 25;20(16):11454-11469. doi: 10.1039/c8cp01508b.
This computational study deals with the collective structure and dynamics as well as their interaction seen from a dielectric viewpoint in zwitterionic reverse micelles for which a force field was designed de novo. For this end, a dualistic strategy is followed: the raw data are generated by extensive microscopic molecular dynamics (MD) simulations while the subsequent analysis has a focus on mesoscopic dielectric properties. The unusually low dielectric signals as well as the remarkable acceleration of collective dynamics is elucidated in great detail. This structural and dynamic behaviour is caused essentially by non-specific micellar boundary conditions. We found that in these ion lacking reverse micelles the water core and the water sheath compensate each other dielectrically which can be understood as a LeChatelier phenomenon facilitating the transition from highly polar encapsulated water to the non-polar low dielectric medium octane. In addition, specific chemical effects are brought about by the perturbing influence of the surfactants. This comprehensive analysis aids both in understanding and designing the dipolar properties of liquid polar spherical colloids dispersed in a hydrophobic medium.
这项计算研究从介电角度探讨了两性离子反胶束中的集体结构与动力学及其相互作用，为此从头设计了一个力场。为此，采用了二元策略：原始数据通过广泛的微观分子动力学（MD）模拟生成，而后续分析则侧重于介观介电性质。异常低的介电信号以及集体动力学的显著加速得到了详细阐释。这种结构和动力学行为主要由非特异性胶束边界条件引起。我们发现，在这些缺乏离子的反胶束中，水核和水鞘在介电方面相互补偿，这可以理解为一种勒夏特列现象，促进了从高极性封装水到非极性低介电介质辛烷的转变。此外，表面活性剂的扰动影响产生了特定的化学效应。这种全面分析有助于理解和设计分散在疏水介质中的液体极性球形胶体的偶极性质。
