Origins of Yielding and Viscoelasticity in Highly Concentrated, Gelled Colloidal Suspensions: An Experimental Study of Microstruture and Rheology

所罗门，美国本文将研究高浓度胶体悬浮液中屈服应力和粘弹性的微观结构起源。 颗粒间的力引起凝胶化、线性粘弹性和屈服。 最近的模型絮凝，渗滤和分形的基础上将进行实验测试，使用模型胶体悬浮液的小和广角光散射方法，因为它们经历屈服过渡和剪切。 几乎折射率匹配的悬浮液的金属氧化物颗粒（球体和杆的可变纵横比）在有机和水性溶剂将被调查的体积分数在0.02和0.2之间。 该项目将检查应变引起的结构变化的暂停之前屈服。 将获得微观结构现象和宏观流变行为之间的联系。 建议的工作具有相关性，在陶瓷，磁存储介质和涂料的制造中的胶体悬浮液的处理。

Abstract9813824M.J. Solomon, U. of MichiganThe microstructural origins of the yield stress and viscoelasticity in highly concentrated colloidal suspensions will be investigated. The interparticle forces give rise to gelation, linear viscoelasticity and yielding. Recent models based on flocculation, percolation and fractals will be experimentally tested using the small and wide-angle light scattering methods of model colloidal suspensions as they undergo yielding transition and shear. Nearly refractive index matched suspensions of metal oxide particles (spheres and rods of variable aspect ratios) in both organic and aqueous solvent will be investigated for volume fractions between 0.02 and 0.2. The project will examine the strain-induced changes in structure of the suspension just prior to yielding. A connection between the microstructural phenomena and macroscopic rheological behavior will be obtained. The proposed work has relevance in processing of colloidal suspensions in the manufacture of ceramics, magnetic storage media and coatings.