Arrested fluid-fluid phase separation in depletion systems: Implications of the characteristic length on gel formation and rheology
Arrested fluid-fluid phase separation in depletion systems: Implications of the characteristic length on gel formation and rheology
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耗尽系统中阻止流体-流体相分离：特征长度对凝胶形成和流变学的影响
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
D. Weitz
中科院分区：
文献类型：
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作者：
J. Conrad;H. Wyss;V. Trappe;S. Manley;K. Miyazaki;L. Kaufman;A. Schofield;D. Reichman;D. Weitz
我们研究了胶体-聚合物混合物的结构，动力学和流变学性质的体积分数范围为0.15-0.35。我们的系统是密度匹配的，剩余电荷被屏蔽，聚合物-胶体尺寸比为0.37。对于这些系统，过渡到动力学逮捕状态，包括断开的集群和凝胶，符合流体-流体相分离边界。结构研究表明，网络的特征长度，L，是一个强大的功能的淬火深度：浅淬火，L是显着大于深淬火。相比之下，L对于给定的淬火深度几乎不依赖于ε;这表明铸坯厚度随着ε的增加而增加。股线厚度决定了线性流变学：最终弛豫时间表现出强烈的依赖性，而高频模量没有。我们提出了一个简单的模型的基础上估计的断股时间和剪切模量，半定量…
We investigate the structural, dynamical, and rheological properties of colloid-polymer mixtures in a volume fraction range of ϕ=0.15–0.35. Our systems are density-matched, residual charges are screened, and the polymer-colloid size ratio is ∼0.37. For these systems, the transition to kinetically arrested states, including disconnected clusters and gels, coincides with the fluid-fluid phase separation boundary. Structural investigations reveal that the characteristic length, L, of the networks is a strong function of the quench depth: for shallow quenches, L is significantly larger than that obtained for deep quenches. By contrast, L is for a given quench depth almost independent of ϕ; this indicates that the strand thickness increases with ϕ. The strand thickness determines the linear rheology: the final relaxation time exhibits a strong dependence on ϕ, whereas the high frequency modulus does not. We present a simple model based on estimates of the strand breaking time and shear modulus that semiquantit...