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锯齿状胶体的自组装和相行为
Self-Assembly and Phase Behaviour of Indented Colloids |
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| 课程网址: |
http://videolectures.net/kolokviji_wilding_phase_behaviour/
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| 主讲教师: |
Nigel B. Wilding
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| 开课单位: |
巴斯大学
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| 开课时间: |
2015-06-01
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| 课程语种: |
英语
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| 中文简介: |
带有压痕的球形胶体可以通过锁键结合的过程形成链，其中一个粒子（锁）的压痕侧整齐地与另一个粒子（键）的凸面配合。当胶体浸没在小得多的聚合物海洋中时，组装会自发发生，导致耗尽相互作用，从而促进键的形成。我们在两个模型中报告了这一过程的模拟和理论研究。首先，我们考虑了在一个由小得多的硬球组成的溶液中，锯齿状胶体的显式混合物。形成的链的形态敏感地取决于胶体压痕的大小，较小的值还允许链分支。与具有吸引斑块的球体的情况相反，Wertheim的热力学微扰理论未能提供聚合转变的完全定量描述。我们将这一失败归因于忽略了堆积效应，并引入了一种改进的理论，该理论可以更好地解释胶体的形状，从而改进了与模拟的一致性。其次，我们将全混合物的模拟映射到一个大大简化的模型，使我们能够研究大型系统的相行为。随着定向和非定向结合比率的增加，液相变得非常紧密，临界点移动到非常低的密度。由此产生的液体具有丰富、开放的结构和有趣的渗流特性。
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| 课程简介: |
Spherical colloids with an indentation can chain via the process of lock-key binding whereby the indented side of one particle (the lock) fits neatly into the convex side of another (the key). Assembly occurs spontaneously when the colloids are immersed in a sea of much smaller polymers leading to depletion interactions which promote bond formation. We report simulation and theoretical studies of this process in two models. Firstly we have considered an explicit mixture of indented colloids in a bath of much smaller hard spheres. The morphology of the chains that are formed depends sensitively on the size of the colloidal indentation, with smaller values additionally permitting chain branching. In contrast to the case of spheres with attractive patches, Wertheim's thermodynamic perturbation theory fails to provide a fully quantitative description of the polymerization transition. We trace this failure to a neglect of packing effects and we introduce a modified theory that accounts better for the shape of the colloids, yielding improved agreement with simulation. Secondly we have mapped simulations of the full mixture to a greatly simplified model allowing us to study the phase behaviour of large systems. As the ratio between directional and non-directional binding increases the liquid phases become very stringy with the critical points moving to very low density. The resulting liquids have a rich, open structure with interesting percolation properties.
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| 关 键 词: |
球形胶体; 聚合物; 锯齿状胶体
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| 课程来源: |
视频讲座网
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| 数据采集: |
2021-11-05：zkj
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| 最后编审: |
2021-11-05：zkj
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| 阅读次数: |
36
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