Lee Johnny Ching-Wei, Porcar Lionel, Rogers Simon A
Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Institut Laue-Langevin, B.P. 156, F-38042 Grenoble CEDEX 9, France.
Polymers (Basel). 2019 Jul 16;11(7):1189. doi: 10.3390/polym11071189.
Understanding how microscopic rearrangements manifest in macroscopic flow responses is one of the central goals of nonlinear rheological studies. Using the sequence-of-physical-processes framework, we present a natural 3D structure-rheology space that temporally correlates the structural and nonlinear viscoelastic parameters. Exploiting the rheo-small-angle neutron scattering (rheo-SANS) techniques, we demonstrate the use of the framework with a model system of polymer-like micelles (PLMs), where we unveil a sequence of microscopic events that micelles experience under dynamic shearing across a range of frequencies. The least-aligned state of the PLMs is observed to migrate from the total strain extreme toward zero strain with increasing frequency. Our proposed 3D space is generic, and can be equally applied to other soft materials under any sort of deformation, such as startup shear or uniaxial extension. This work therefore provides a natural approach for researchers to study complex out-of-equilibrium structure-rheology relationships of soft materials.
理解微观重排在宏观流动响应中的表现是非线性流变学研究的核心目标之一。利用物理过程序列框架，我们提出了一个自然的三维结构-流变学空间，该空间在时间上关联了结构和非线性粘弹性参数。利用流变小角中子散射（rheo-SANS）技术，我们在类聚合物胶束（PLM）的模型系统中演示了该框架的应用，在该系统中，我们揭示了胶束在一系列频率下动态剪切时所经历的微观事件序列。观察到PLM的最无序状态随着频率增加从总应变极值向零应变迁移。我们提出的三维空间具有通用性，可同样应用于任何类型变形下的其他软材料，如启动剪切或单轴拉伸。因此，这项工作为研究人员提供了一种自然的方法来研究软材料复杂的非平衡结构-流变学关系。
