Everts Jeffrey C, Ravnik Miha
Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000, Ljubljana, Slovenia.
Department of Condensed Matter Physics, Jozef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia.
Sci Rep. 2018 Sep 20;8(1):14119. doi: 10.1038/s41598-018-32550-8.
Charged surfaces in contact with liquids containing ions are accompanied in equilibrium by an electric double layer consisting of a layer of electric charge on the surface that is screened by a diffuse ion cloud in the bulk fluid. This screening cloud determines not only the interactions between charged colloidal particles or polyelectrolytes and their self-assembly into ordered structures, but it is also pivotal in understanding energy storage devices, such as electrochemical cells and supercapacitors. However, little is known to what spatial complexity the electric double layers can be designed. Here, we show that electric double layers of non-trivial topology and geometry -including tori, multi-tori and knots- can be realised in charged topological colloidal particles, using numerical modelling within a mean-field Poisson-Boltzmann theory. We show that the complexity of double layers -including geometry and topology- can be tuned by changing the Debye screening length of the medium, or by changing the shape and topology of the (colloidal) particle. More generally, this work is an attempt to introduce concepts of topology in the field of charged colloids, which could lead to novel exciting material design paradigms.
与含离子液体接触的带电表面在平衡状态下伴随着一个双电层，该双电层由表面的一层电荷组成，这层电荷被体相流体中的扩散离子云所屏蔽。这个屏蔽云不仅决定了带电胶体颗粒或聚电解质之间的相互作用以及它们自组装成有序结构的过程，而且对于理解诸如电化学电池和超级电容器等能量存储装置也至关重要。然而，对于双电层能够被设计到何种空间复杂度，人们了解甚少。在这里，我们表明，使用平均场泊松 - 玻尔兹曼理论中的数值模拟，在带电拓扑胶体颗粒中可以实现具有非平凡拓扑和几何形状的双电层，包括环面、多环面和纽结。我们表明，双电层的复杂度，包括几何形状和拓扑结构，可以通过改变介质的德拜屏蔽长度，或者通过改变（胶体）颗粒的形状和拓扑结构来调节。更一般地说，这项工作试图在带电胶体领域引入拓扑学概念，这可能会带来新颖且令人兴奋的材料设计范例。
