Sung Bong June, Yethiraj Arun
Theoretical Chemistry Institute and Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, USA.
J Chem Phys. 2005 Jun 15;122(23):234904. doi: 10.1063/1.1931649.
A self-consistent integral equation theory is presented for the conformational properties and spinodal lines of random copolymer melts. The theory combines field-theoretic methods with the polymer reference interaction site model (PRISM) theory. The many-chain problem is replaced by a single chain where the sites interact via a bare plus a self-consistently determined medium-induced potential, and the conformational properties are obtained using a variational method. The theoretical prediction for the spinodal line is qualitatively similar to that of non-self-consistent PRISM theory. The theory predicts macroscopic phase separation for all values of the monomer correlation strength, lambda. The inverse spinodal temperature is a nonmonotonic function of lambda with a maximum at lambda(max). For large values of lambda( approximately 1), the values of spinodal temperatures are almost identical to those of non-self-consistent PRISM theory. For low values of lambda, however, the theory predicts higher values for spinodal temperatures than non-self-consistent PRISM theory. The theory predicts significant changes in the mean-square end-to-end distance as the temperature is decreased.
提出了一种自洽积分方程理论，用于研究无规共聚物熔体的构象性质和旋节线。该理论将场论方法与聚合物参考相互作用位点模型（PRISM）理论相结合。多链问题被单个链问题所取代，其中位点通过裸势加上自洽确定的介质诱导势相互作用，并使用变分方法获得构象性质。旋节线的理论预测在定性上与非自洽PRISM理论相似。该理论预测了单体相关强度λ的所有值下的宏观相分离。逆旋节温度是λ的非单调函数，在λ(max)处有最大值。对于较大的λ值（约为1），旋节温度的值几乎与非自洽PRISM理论的值相同。然而，对于较低的λ值，该理论预测的旋节温度值比非自洽PRISM理论更高。该理论预测，随着温度降低，均方末端距会发生显著变化。
