Zackrisson Malin, Stradner Anna, Schurtenberger Peter, Bergenholtz Johan
Department of Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden.
Phys Rev E Stat Nonlin Soft Matter Phys. 2006 Jan;73(1 Pt 1):011408. doi: 10.1103/PhysRevE.73.011408. Epub 2006 Jan 24.
A comprehensive experimental study of the dynamics and rheology of concentrated aqueous dispersions of poly(ethylene glycol)-grafted colloidal spheres is reported. The study focuses on good solvent conditions, for which excluded-volume interactions dominate. At high concentrations a glass transition is evident from the nondecaying component of the intensity correlation function measured with three-dimensional dynamic light scattering. Results for the linear viscoelastic and steady shear rheology on approaching the glass transition correlate well with the slowing of the diffusive dynamics; in particular, at, or close to, the concentration where the dynamics becomes nonergodic, the dispersions acquire a low-frequency plateau in the elastic shear modulus as well as a yield stress. The overall behavior of the dispersions conforms to that of hard-sphere dispersions; however, some qualitative differences are observed in the evolution of the dynamics and rheology with increasing concentration near the glass transition.
本文报道了聚（乙二醇）接枝胶体球浓水分散体系动力学和流变学的综合实验研究。该研究聚焦于良溶剂条件，此时排除体积相互作用占主导。在高浓度下，通过三维动态光散射测量的强度相关函数的非衰减分量明显显示出玻璃化转变。接近玻璃化转变时线性粘弹性和稳态剪切流变学的结果与扩散动力学的减慢密切相关；特别是在动力学变为非遍历性的浓度处或接近该浓度时，分散体系在弹性剪切模量中获得低频平台以及屈服应力。分散体系的整体行为符合硬球分散体系；然而，在接近玻璃化转变时，随着浓度增加，动力学和流变学的演变存在一些定性差异。
