Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
Proc Natl Acad Sci U S A. 2012 Jun 26;109(26):10187-92. doi: 10.1073/pnas.1202171109. Epub 2012 Jun 7.
Nanostructured materials based on colloidal particles embedded in a polymer network are used in a variety of applications ranging from nanocomposite rubbers to organic-inorganic hybrid solar cells. Further, polymer-network-mediated colloidal interactions are highly relevant to biological studies whereby polymer hydrogels are commonly employed to probe the mechanical response of living cells, which can determine their biological function in physiological environments. The performance of nanomaterials crucially relies upon the spatial organization of the colloidal particles within the polymer network that depends, in turn, on the effective interactions between the particles in the medium. Existing models based on nonlocal equilibrium thermodynamics fail to clarify the nature of these interactions, precluding the way toward the rational design of polymer-composite materials. In this article, we present a predictive analytical theory of these interactions based on a coarse-grained model for polymer networks. We apply the theory to the case of colloids partially embedded in cross-linked polymer substrates and clarify the origin of attractive interactions recently observed experimentally. Monte Carlo simulation results that quantitatively confirm the theoretical predictions are also presented.
基于胶体颗粒嵌入聚合物网络的纳米结构材料被应用于从纳米复合橡胶到有机-无机杂化太阳能电池等多种应用中。此外，聚合物网络介导的胶体相互作用与生物研究密切相关，其中聚合物水凝胶常用于探测活细胞的机械响应，这可以确定它们在生理环境中的生物学功能。纳米材料的性能取决于胶体颗粒在聚合物网络中的空间组织，而这又取决于介质中颗粒之间的有效相互作用。基于非局部平衡热力学的现有模型未能阐明这些相互作用的本质，从而阻碍了对聚合物复合材料进行合理设计的道路。在本文中，我们提出了一种基于聚合物网络粗粒化模型的这些相互作用的预测分析理论。我们将理论应用于部分嵌入交联聚合物基底的胶体的情况，并阐明了最近实验中观察到的吸引力相互作用的起源。还提出了定量证实理论预测的蒙特卡罗模拟结果。
