表面接枝二分散聚合物的自洽场理论

Self-consistent theory of bidisperse polymers grafted to surface

建立了表面接枝多分散聚合物的自洽场理论.通过对二分散聚合物进行自洽场模拟,研究了排除体积参数对分子链密度分布的影响,考察了分子链的摩尔分数与自由端分布的关系并将模拟结果与强伸展理论进行了比较.通过计算分子链的链段密度分布和伸展轨迹,讨论了二分散聚合物分子链的伸展行为.

A self-consistent field theory （SCFT） for polydisperse polymers grafted to a surface was developed. By solving the resulting equations numerically, both density profiles and free end distributions for bidisperse polymers consisting of two different chain lengths were simulated with moderate to strong excluded volume interactions. The results showed that the monolayer of bidisperse polymers separated into two sublayers as excluded volume interactions increased. The density profiles simulated by the selfconsistent field theory were consistent with the results of the strong stretching theory when excludedvolume interactions were high. Also the free end distributions of long chains were close to the prediction of strong-stretching theory （SST） in that case. But the free end distributions of short chains deviated from the SST results evidently. The average trajectories for both short and long chains were calculated. It revealed that short chains in bidisperse polymers were less stretching than the monodisperse chains with the same chain length. However long chains in bidisperse polymers were more stretching than the monodisperse chains with the same chain length in the inner layer and less stretching than that in the outer layer.