Microstructure-dependent viscosity in concentrated suspensions of soft spheres

被引:29
作者
Paulin, SE
Ackerson, BJ
Wolfe, MS
机构
[1] OKLAHOMA STATE UNIV,DEPT PHYS,STILLWATER,OK 74078
[2] DUPONT CO INC,WILMINGTON,DE 19880
来源
PHYSICAL REVIEW E | 1997年 / 55卷 / 05期
关键词
D O I
10.1103/PhysRevE.55.5812
中图分类号
O35 [流体力学]; O53 [等离子体物理学];
学科分类号
070204 ; 080103 ; 080704 ;
摘要
Monodisperse colloidal suspensions of polymethylmethacrylate spheres swollen in benzyl alcohol have been theologically examined under applied steady and oscillatory shear while simultaneously monitoring microstructure via light scattering, In concentrated samples, long-lived nonequilibrium microstructures can be induced, corresponding to random hexagonal-close-packed planes (hcp) stacked in the direction of the shear gradient. The direction of closest packing within each hcp plane fan be oriented along either the vorticity or direction of flow. Creep and creep recovery measurements have been examined for each of these two orientations as a function of particle concentration and stress. Results indicate a strain-dependent dissipative profess correlated with changes sample microstructure, while dynamic measurements of the storage modulus show no significant difference between microstructures. We argue that instantaneous viscosities can be measured and show how they are correlated with changes in particle microstructure. The observed elastic response in these suspensions will be shown to be due to local microstructure and particle deformation.
引用
收藏
页码:5812 / 5819
页数:8
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