Kłos J S, Sommer J-U
Leibniz Institute of Polymer Research Dresden e. V., 01069 Dresden, Germany.
J Chem Phys. 2008 Apr 28;128(16):164908. doi: 10.1063/1.2894870.
We use scaling arguments and computer simulations to investigate the adsorption of symmetric AB-random copolymers (RC) from a diluted solution onto a selective ABA layer. Depending on the ratio between the layer thickness and the size of excess blobs, d/xi, three regimes of RC adsorption are predicted. For large values of the layer thickness RC adsorption can be understood as adsorption on two selective interfaces where sequences of RC chains form bridges. When the layer thickness is of the order of xi, excess blobs are trapped in the layer and localize the copolymer chain strongly. If the layer thickness is very small a weak adsorption scenario is predicted where large loops are formed outside the layer. Our simulations using the bond fluctuation model are in good agreement with the scaling predictions. We show that chain properties display non-monotonous behavior with respect to the layer thickness with optimal values for d approximately xi. In particular, we discuss simulation results for density profiles, statistics of bridges, loops and tails formed by the adsorbed chains, as well as for the adsorption order parameter and free energy.
我们使用标度论证和计算机模拟来研究对称AB-无规共聚物（RC）从稀溶液吸附到选择性ABA层上的情况。根据层厚度与过量链段尺寸的比值d/ξ，预测了RC吸附的三种情况。对于较大的层厚度值，RC吸附可理解为在两个选择性界面上的吸附，其中RC链序列形成桥。当层厚度约为ξ时，过量链段被困在层中并强烈地使共聚物链定位。如果层厚度非常小，则预测会出现弱吸附情况，此时在层外形成大环。我们使用键涨落模型进行的模拟与标度预测结果吻合良好。我们表明，链的性质相对于层厚度呈现非单调行为，d约为ξ时有最优值。特别是，我们讨论了密度分布、吸附链形成的桥、环和尾的统计数据，以及吸附序参量和自由能的模拟结果。
