Schäfer Ken, Kolli Hima Bindu, Killingmoe Christensen Mikkel, Bore Sigbjørn Løland, Diezemann Gregor, Gauss Jürgen, Milano Giuseppe, Lund Reidar, Cascella Michele
Department Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128, Mainz, Germany.
Department of Physics and Astronomy, The University of Sheffield, Western Bank, Sheffield, S10 2TN, UK.
Angew Chem Int Ed Engl. 2020 Oct 12;59(42):18591-18598. doi: 10.1002/anie.202004522. Epub 2020 Aug 17.
The shape and size of self-assembled structures upon local organization of their molecular building blocks are hard to predict in the presence of long-range interactions. Combining small-angle X-ray/neutron scattering data, theoretical modelling, and computer simulations, sodium dodecyl sulfate (SDS), over a broad range of concentrations and ionic strengths, was investigated. Computer simulations indicate that micellar shape changes are associated with different binding of the counterions. By employing a toy model based on point charges on a surface, and comparing it to experiments and simulations, it is demonstrated that the observed morphological changes are caused by symmetry breaking of the irreducible building blocks, with the formation of transient surfactant dimers mediated by the counterions that promote the stabilization of cylindrical instead of spherical micelles. The present model is of general applicability and can be extended to all systems controlled by the presence of mobile charges.
在存在长程相互作用的情况下，由其分子构建块局部组织而成的自组装结构的形状和大小很难预测。结合小角X射线/中子散射数据、理论建模和计算机模拟，对十二烷基硫酸钠（SDS）在广泛的浓度和离子强度范围内进行了研究。计算机模拟表明，胶束形状的变化与抗衡离子的不同结合有关。通过采用基于表面点电荷的简化模型，并将其与实验和模拟结果进行比较，证明观察到的形态变化是由不可约构建块的对称性破缺引起的，由抗衡离子介导形成瞬态表面活性剂二聚体，促进了圆柱形而非球形胶束的稳定。本模型具有普遍适用性，可扩展到所有受移动电荷存在控制的系统。
