Instituto de Física, Universidade Federal de Ouro Preto, CEP 35400-000, Ouro Preto, MG, Brazil.
Soft Matter. 2018 Jun 20;14(24):5106-5120. doi: 10.1039/c8sm00441b.
Using molecular dynamics simulations, we investigate the self-assembly of a coarse-grained binary system of oppositely charged microgels, symmetric in size and concentration. The microgel pair interactions are described by an effective pair potential which implicitly accounts for the averaged ionic contributions, in addition to a short-range elastic repulsion that accounts for the overlapping of the polymer chains, the latter being described by the Hertzian interaction. Particular emphasis is placed on the role played by the strength of the soft repulsive interaction on the resulting particle aggregation. It is found that the possibility of particle inter-penetration in oppositely charged soft particles results in a much wider variety of cluster morphologies in comparison with their hard-spheres counterparts. Specifically, the softness of the steric interactions enhances the competition between repulsive and attractive electrostatic interactions, leading to the formation of aggregates that are comprised of strongly bounded charged particles displaying a low degree of charge ordering.
利用分子动力学模拟，我们研究了大小和浓度对称的带相反电荷的微凝胶粗粒化二元体系的自组装。微凝胶对之间的相互作用由有效对势能描述，该势能除了短程弹性排斥外，还隐式地考虑了平均离子贡献，后者由赫兹相互作用描述。特别强调了软排斥相互作用强度对所得颗粒聚集的作用。结果发现，与硬球相比，带相反电荷的软颗粒的颗粒相互贯穿的可能性导致了更广泛的团簇形态。具体而言，位阻相互作用的柔软度增强了排斥和吸引力静电相互作用之间的竞争，导致形成由强烈结合的带电粒子组成的聚集体，这些聚集体显示出低程度的电荷有序。
