Mewis Jan, Wagner Norman J
Department of Chemical Engineering, K.U.Leuven, de Croylaan 46, 3001, Belgium.
Adv Colloid Interface Sci. 2009 Mar-Jun;147-148:214-27. doi: 10.1016/j.cis.2008.09.005. Epub 2008 Oct 2.
Flow can induce reversible and irreversible structural changes in dispersions. The analysis of flow effects on microstructure and rheology remains one of the challenging problems in colloid science. The rheological manifestation of flow-induced structural changes is a variable viscosity. If the changes are reversible and time dependent, the effect is called thixotropy. The basic elements of this concept are reviewed here, including its definition and the relation with nonlinear viscoelasticity. The omnipresence of thixotropy is illustrated with a wide range of examples from natural and manmade colloidal systems. Its various rheological manifestations are reviewed as well as possible measurement procedures. The microstructural changes due to flow are quite complex and not fully understood. Existing models for thixotropic suspension rheology are categorized and evaluated.
流动可在分散体系中引起可逆和不可逆的结构变化。分析流动对微观结构和流变学的影响仍然是胶体科学中具有挑战性的问题之一。流动诱导结构变化的流变学表现是粘度可变。如果这些变化是可逆的且与时间相关，则这种效应称为触变性。本文综述了这一概念的基本要素，包括其定义以及与非线性粘弹性的关系。通过自然和人造胶体系统的大量实例说明了触变性的普遍存在。还综述了其各种流变学表现以及可能的测量方法。流动引起的微观结构变化相当复杂，尚未完全理解。对现有的触变悬浮液流变学模型进行了分类和评估。
