Department of Structural Dynamics of (Bio)chemical Systems, Max Planck Institute for Biophysical Chemistry, 37070 Göttingen, Germany.
J Phys Chem A. 2011 Mar 24;115(11):2176-83. doi: 10.1021/jp1108224. Epub 2011 Feb 25.
A manifold of ordering transitions relevant to chemical and biological systems occur at interfaces from liquids to self-assembled soft solids like membranes or liquid crystals. In the present case, we were interested in understanding the phase transition from the microemulsion phase to the liquid crystal phase in terms of their driving forces, i.e., activation energy and entropy. The purpose of this work was to clarify the influence of concentration effects of the amphiphilic molecules on the nature of these self-assembly processes. By photosensitization of the model system (polyalkylglycolether (C(10)E(4)), water, decane, and cyclohexane) with laser dyes, we could effectively induce and control the phase transition through the absorption of optical photons. The photo transformation conditions were chosen in such a way that the system was in thermal equilibrium. By application of time-resolved photo small-angle X-ray scattering we could monitor the conversion process and demonstrate that the surfactant concentration has a direct impact on the activation energy, which is observable through the length of the induction time.
与化学和生物系统相关的有序相变流形发生在从液体到自组装软固体（如膜或液晶）的界面上。在本案例中，我们感兴趣的是从微乳液相到液晶相的相转变，涉及到驱动力，即激活能和熵。这项工作的目的是澄清两亲分子的浓度效应对这些自组装过程性质的影响。通过用光致染料敏化模型体系（聚烷氧基乙二醇醚（C(10)E(4)）、水、癸烷和环己烷），我们可以通过吸收光量子有效地诱导和控制相转变。光转换条件的选择方式使得体系处于热平衡状态。通过应用时间分辨光小角 X 射线散射，我们可以监测转化过程，并证明表面活性剂浓度对激活能有直接影响，这可以通过诱导时间的长短来观察到。
