利用TDGL方法模拟嵌段共聚物链长和浓度对A/B/A-B三组分体系相形态演化的影响

从Flory-Huggins自由能出发,得到了适合TDGL模拟的自由能泛函.在自由能中保留了各序参量的耦合项,并且还保留了链长的信息.利用自由能中的链长的信息,模拟了不同嵌段共聚物链长以及不同浓度下体系的形态变化,在均聚物的链长和浓度确定的条件下,存在一个使体系的相区尺寸最小的最佳嵌段共聚物链长.同时,在嵌段共聚物和均聚物的链长都一定的情况下,研究了不同量的嵌段共聚物对体系相行为的影响,发现嵌段共聚物的浓度不同,体系的结构存在很大的区别.此外,如果均聚物A和B的浓度不同,其相区的结构也不同.

Effects of Chain Length and Concentration of Block Copolymer on the Phase Separation of A/B/A-B System by TDGL Simulation

The free energy functional for the time dependent Ginzburg-Landau equation were obtained by means of Flory-Huggins free energy. The couplings between different order parameters and the chain lengths were included. The phase behavior of A/B/A-B system at different A-B chain lengths and concentrations were simulated. For the same chain length and concentration of homopolymer A and B, there is an optimum chain length of diblock copolymer to minimize the mean domain size. At the fixed chain length of the homopolymer and diblock copolymer, the structures of the mixture are greatly different when the concentration of diblock copolymer is different. Furthermore, the phase domain structures are different at different concentrations of homopolymer A and B.