Sung Bong June, Yethiraj Arun
Theoretical Chemistry Institute and Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, USA.
J Chem Phys. 2005 Aug 15;123(7):074909. doi: 10.1063/1.2008232.
The conformational properties and static structure of freely jointed hard-sphere chains in matrices composed of stationary hard spheres are studied using Monte Carlo simulations and integral equation theory. The simulations show that the chain size is a nonmonotonic function of the matrix density when the matrix spheres are the same size as the monomers. When the matrix spheres are of the order of the chain size the chain size decreases monotonically with increasing matrix volume fraction. The simulations are used to test the replica-symmetric polymer reference interaction site model (RSP) integral equation theory. When the simulation results for the intramolecular correlation functions are input into the theory, the agreement between theoretical predictions and simulation results for the pair-correlation functions is quantitative only at the highest fluid volume fractions and for small matrix sphere sizes. The RSP theory is also implemented in a self-consistent fashion, i.e., the intramolecular and intermolecular correlation functions are calculated self-consistently by combining a field theory with the integral equations. The theory captures qualitative trends observed in the simulations, such as the nonmonotonic dependence of the chain size on media fraction.
利用蒙特卡罗模拟和积分方程理论，研究了由静止硬球组成的基质中自由连接硬球链的构象性质和静态结构。模拟结果表明，当基质球体与单体大小相同时，链尺寸是基质密度的非单调函数。当基质球体尺寸与链尺寸相当时，链尺寸随基质体积分数的增加而单调减小。这些模拟用于检验复制对称聚合物参考相互作用位点模型（RSP）积分方程理论。当将分子内相关函数的模拟结果输入该理论时，仅在最高流体体积分数和小基质球体尺寸下，对关联函数的理论预测与模拟结果之间的一致性才是定量的。RSP理论也以自洽方式实现，即通过将场论与积分方程相结合，自洽地计算分子内和分子间相关函数。该理论捕捉到了模拟中观察到的定性趋势，如链尺寸对介质分数的非单调依赖性。
