高分子链相关函数与液体小分子速度/应力-时间相关函数的可类比性  

LONG-RANGE CORRELATIONS IN A POLYMER CHAIN AND LONG-TAIL IN VELOCITY/STRESS CORRELATION FUNCTION IN MOLECULAR LIQUID

作　　者：熊志敏[1,2] 廖琦[1] 金熹高[1] 韩志超[1] 

机构地区：[1]中国科学院化学研究所、北京分子科学国家实验室、高分子物理与化学国家重点实验室,北京100190 [2]中国科学院研究生院,北京100049

出　　处：《高分子学报》2012年第6期685-688,共4页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号20974115)资助

摘　　要：通过标度关系,给出了良溶剂和熔体或θ溶剂中真实高分子链相关函数的幂率衰减关系.这一问题的物理背景,与液体中小分子速度和应力的时间相关函数的长时间拖尾现象,具有可类比的物理图像,但是由于高分子系统的复杂性,高分子的链相关函数表现出更复杂和丰富的可能形式.Starting from the long-tail in molecular liquid velocity correlation function, the same long-tail in the stress correlation function of molecular liquid is obtained by computer simulation. By using the scaling picture, it is shown that the long-range correlations in a polymer chain and the long-tail in velocity/stress correlation function in the molecular liquid share the same physical mechanism. Both of the velocity/stress correlation function and the bond vector correlation function have analogous characteristics. Instead of the exponential decay predicted by the classic model of the random walk, the new power-law decay of bond-vector correlation function in polymer chains is clearly explained. The bond vector correlation functions for chains in good and theta solvents are decayed as a power law with exponent 2v - 2 and - 3/2 ,respectively.

关 键 词：高分子链相关函数 幂率衰减 指数衰减 长时间拖尾 

分 类 号：O631.2[理学—高分子化学]