Physical Chemistry, Department of Chemistry, Lund University, 221 00 Lund, Sweden.
Langmuir. 2013 Aug 20;29(33):10346-59. doi: 10.1021/la4016542. Epub 2013 Aug 8.
We use a combination of different scattering techniques and rheology to highlight the link between structure and dynamics of dense aqueous suspensions of soft repulsive colloids in the vicinity of a glass transition. Three different latex formulations with an increasing amount of the hydrophilic component resulting in either purely electrostatically or electrosterically stabilized suspensions are investigated. From the analysis of the static structure factor measured by small-angle X-ray scattering, we derive an effective volume fraction that includes contributions from interparticle interactions. We further investigate the dynamics of the suspensions using 3D cross-correlation dynamic light scattering (3DDLS) and rheology. We analyze the data using an effective hard sphere model and in particular compare the linear viscoelasticity and flow behavior to the predictions of mode coupling theory, which accounts for a purely kinetic glass transition determined by the equilibrium structure factor. We demonstrate that seemingly very different colloidal systems exhibit the same generic behavior when the effects from interparticle interactions are incorporated using an effective volume fraction description.
我们使用多种散射技术和流变学相结合的方法，强调了在玻璃化转变附近，具有软斥力胶体的密集水悬浮液的结构与动力学之间的联系。我们研究了三种不同的乳胶配方，其中亲水性成分的含量逐渐增加，导致悬浮液完全由静电或电稳定。通过对小角度 X 射线散射测量的静态结构因子的分析，我们得出了一个有效体积分数，其中包括了颗粒间相互作用的贡献。我们进一步使用三维互相关动态光散射（3DDLS）和流变学研究了悬浮液的动力学。我们使用有效硬球模型分析数据，特别是将线性粘弹性和流动行为与模式耦合理论的预测进行比较，该理论考虑了由平衡结构因子决定的纯动力学玻璃化转变。我们证明了，当使用有效体积分数描述来包含颗粒间相互作用的影响时，看似非常不同的胶体系统表现出相同的一般行为。
