端点附壁的高分子链形状的MonteCarlo模拟

A Monte Carlo Simulation on Shape of Grafted Polymer Chains

分别基于简立方格点和四面体格点模型对一端吸附在无限大平面的高分子链 (平面接枝高分子链 )的形状进行了 Monte Carlo摸拟 .结果表明 ,接枝高分子链的形状更偏离球形 ,〈L1 2〉∶〈L2 2〉∶〈L32〉的极限值约为 1∶ 2 .75∶ 1 2 .5,其中〈L1 2 〉,〈L2 2 〉和〈L32 〉分别为回转半径张量的本征值 L1 2 ,L2 2 和 L32 ( L1 2 <L2 2 <L32 )的统计平均 ;链长相同时 ,接枝高分子链的比值〈L2 2 〉/〈L1 2 〉和〈L32 〉/〈L1 2 〉均比自由 (稀溶液中 )高分子链的大 ,且与高分子链的格点模型有关 .

The shape of polymer chain on a simple cubic and a tetrahedral lattice, with one end absorbed by an impermeable wall, was studied with Monte Carlo technique. The results show that the shape of grafted polymer chains is more deviated from sphere than that of free ones. The limit value of 〈 L 1 2〉∶〈 L 2 2〉∶〈 L 3 2〉 of grafted polymer chains is about 1∶2.75∶12.5; the values of 〈 L 2 2〉/〈 L 1 2〉 and 〈 L 3 2〉/〈 L 1 2〉 of grafted polymer chains are bigger than those of free ones, they decrease with the increase of chain length. It is found that the deviation of 〈 L 2 2〉/〈 L 1 2〉 and 〈 L 3 2〉/〈 L 1 2〉 of grafted polymer chains from those of free ones depends on chain′s lattice model.