Hatami-Marbini Hamed
Mechanical and Industrial Engineering Department, University of Illinois at Chicago, Chicago IL, United States of America.
J Phys Condens Matter. 2020 Jun 24;32(27):275101. doi: 10.1088/1361-648X/ab76ab.
Colloidal gel networks appear in different scientific and industrial applications because of their unique properties. Molecular dynamics simulations could reveal the relation between molecular level and macroscopic properties of these systems. Nevertheless, the predictions of numerical simulations might depend on the specific form and parameters of interaction potentials. In this paper, a new effective interaction potential is used for characterizing the mechanical behavior of low volume fraction colloidal gels under large shear deformation. The findings are compared with those obtained from other available forms of interaction potentials in order to determine gel characteristics that are interaction potential independent. Furthermore, the macroscopic stress-strain behavior is discussed in terms of the behavior of different terms of the proposed interaction potential. The correlation between the stretch of interparticle bonds and their alignment in the direction of the maximum principal stress is also computed in order to provide microscopic explanations for the initial strain softening behavior. It is concluded that, in addition to topology, local mechanical interactions between colloidal particles are important in defining the mechanical response of soft gels.
由于其独特的性质，胶体凝胶网络出现在不同的科学和工业应用中。分子动力学模拟可以揭示这些系统在分子水平和宏观性质之间的关系。然而，数值模拟的预测可能取决于相互作用势的具体形式和参数。在本文中，一种新的有效相互作用势被用于表征低体积分数胶体凝胶在大剪切变形下的力学行为。将这些发现与从其他可用的相互作用势形式获得的结果进行比较，以确定与相互作用势无关的凝胶特性。此外，根据所提出的相互作用势的不同项的行为来讨论宏观应力-应变行为。还计算了粒子间键的拉伸与其在最大主应力方向上的排列之间的相关性，以便为初始应变软化行为提供微观解释。得出的结论是，除了拓扑结构外，胶体颗粒之间的局部力学相互作用在定义软凝胶的力学响应方面也很重要。
