单分子链穿插进入双链凝聚线团的分子动力学方法模拟  

Molecular Dynamics Simulation of Single Polymer Chain Interpenetrating into a Two-chain Condensed Coils

作　　者：张竹青[1] 杨小震[1] 

机构地区：[1]中国科学院化学研究所

出　　处：《高等学校化学学报》2004年第5期975-978,共4页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号 :2 0 0 740 41);"八六三"项目;"九七三"项目(批准号 :G19990 64 80 7)资助

摘　　要：用分子动力学 ( MD)方法模拟了聚乙烯 (含 3 0 0个 CH2 单元 )单链凝聚线团与一个双链处于平衡态的凝聚线团相互穿插的融合过程 ,考察分析了体系结构演变的能量信息及第三个链的引入对原来两链穿插状态的影响 .研究发现 ,在两部分线团凝聚成一体后 ,各分子链一方面在表面势能各向异性的作用下试图挤入体系内部 ,另一方面在构象熵的驱动下又尽可能地占据体系的空间 ,线团的穿插是在两者共同作用下逐步完成的 .第三个链的融入使得原来两个链的质心距离有所增加 。A merging process of one condensed polyethylene chain into a two-chain globule(each of which consists of 300 CH 2) was simulated by molecular dynamics. Examination of the energy variation during whole structural evolution and evaluation of the perturbation of new chain to the well-penetrated two chains were performed. It was found that after the two parts become one globule, each of the chains attempts either to be inside under anisotropy of surface tension, or to occupy all the space possibly in the system by conformational entropy. The interpenetration process was thus carried out under such competition. It was also found that the third chain perturbs the distance between mass centers of the two previous chains and causes the distance increasing, which was also supported by the radial distribution function analysis.

关 键 词：双链凝聚线团 分子动力学 单分子链 相互穿插 高分子材料 

分 类 号：TB324[一般工业技术—材料科学与工程]