Yang Qing-Hui, Qi Hang-Kai, Yang Xiao, Luo Meng-Bo
Department of Physics, Hangzhou Dianzi University, Hangzhou 310018, China.
Soft Matter. 2021 Jan 28;17(4):1000-1007. doi: 10.1039/d0sm01721c. Epub 2020 Dec 7.
The critical adsorption and diffusion of a linear polymer chain on a heterogeneous surface with randomly distributed adsorption sites are studied using dynamic Monte Carlo simulations. Results show that the critical fraction of the adsorption sites at which critical adsorption takes place decreases exponentially with the increasing polymer-surface attraction strength and, at the same time, decreases with the increasing intra-polymer attraction strength. For adsorbed polymers with large intra-polymer attraction strength, we also find an adsorption-induced structural transition from a three-dimensional compact globule to a two-dimensional compacted pancake with an increasing fraction of adsorption sites. Anomalous sub-diffusion is observed for the adsorbed polymer diffusion on heterogeneous surfaces, in contrast to the normal diffusion on a homogeneous surface. The polymer on heterogeneous surfaces shows larger fluctuation in the total surface attraction energy and a longer waiting time.
利用动态蒙特卡罗模拟研究了线性聚合物链在具有随机分布吸附位点的非均匀表面上的临界吸附和扩散。结果表明，发生临界吸附时吸附位点的临界分数随聚合物-表面吸引强度的增加呈指数下降，同时也随聚合物内吸引强度的增加而下降。对于具有较大聚合物内吸引强度的吸附聚合物，我们还发现随着吸附位点分数的增加，会发生从三维紧密球状体到二维压实薄饼的吸附诱导结构转变。与在均匀表面上的正常扩散相反，在非均匀表面上观察到吸附聚合物扩散的反常亚扩散。非均匀表面上的聚合物在总表面吸引能上表现出更大的波动和更长的等待时间。
