聚合物结构与构象的密度泛函理论

Wei Zhaoyang, Ning Nanying, Zhang Liqun, Tian Ming, Mi Jianguo

State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China.

Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, China.

Polymers (Basel). 2016 Apr 15;8(4):121. doi: 10.3390/polym8040121.

We present a density functional approach to quantitatively evaluate the microscopic conformations of polymer chains with consideration of the effects of chain stiffness, polymer concentration, and short chain molecules. For polystyrene (PS), poly(ethylene oxide) (PEO), and poly(methyl methacrylate) (PMMA) melts with low-polymerization degree, as chain length increases, they display different stretching ratios and show non-universal scaling exponents due to their different chain stiffnesses. In good solvent, increase of PS concentration induces the decline of gyration radius. For PS blends containing short (m₁ = 1 - 100) and long (m = 100) chains, the expansion of long chains becomes unobvious once m 1 is larger than 40, which is also different to the scaling properties of ideal chain blends.

我们提出了一种密度泛函方法，用于在考虑链刚度、聚合物浓度和短链分子影响的情况下，定量评估聚合物链的微观构象。对于低聚合度的聚苯乙烯（PS）、聚环氧乙烷（PEO）和聚甲基丙烯酸甲酯（PMMA）熔体，随着链长增加，由于它们不同的链刚度，它们表现出不同的拉伸比并显示出非通用的标度指数。在良溶剂中，PS浓度的增加会导致回转半径下降。对于含有短链（m₁ = 1 - 100）和长链（m = 100）的PS共混物，一旦m₁大于40，长链的扩张就变得不明显，这也与理想链共混物的标度性质不同。