论文标题
通过竞争相互作用调整胶体凝胶的流变行为
Tuning the rheological behavior of colloidal gels through competing interactions
论文作者
论文摘要
我们研究通过在外部剪切下进行广泛的数值模拟而形成的胶体凝胶。我们表明，在改变排斥强度后，可以在很大程度上调整凝胶结构及其粘弹性。特别是，相对于机械平衡条件，凝胶分形尺寸可以增加或减小。出乎意料的是，尽管机械上的凝结剂具有更强的凝胶，但就纯粹有吸引力的凝胶而言，凝胶的粘性较小。我们根据基础分离的影响提供了这些发现的微观解释。我们的结果允许通过其他静电相互作用来设计具有所需结构和粘弹性响应的胶体凝胶，在实验中易于控制。
We study colloidal gels formed by competing electrostatic repulsion and short-range attraction by means of extensive numerical simulations under external shear. We show that, upon varying the repulsion strength, the gel structure and its viscoelastic properties can be largely tuned. In particular, the gel fractal dimension can be either increased or decreased with respect to mechanical equilibrium conditions. Unexpectedly, gels with stronger repulsion, despite being mechanically stiffer, are found to be less viscous with respect to purely attractive ones. We provide a microscopic explanation of these findings in terms of the influence of an underlying phase separation. Our results allow for the design of colloidal gels with desired structure and viscoelastic response by means of additional electrostatic interactions, easily controllable in experiments.
