Monte Carlo study of the micelles constructed by ABCA tetrablock copolymers and their formation in A-selective solvents
Monte Carlo study of the micelles constructed by ABCA tetrablock copolymers and their formation in A-selective solvents
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ABCA 四嵌段共聚物构建的胶束及其在 A 选择性溶剂中形成的蒙特卡罗研究
DOI：
10.1039/c5ra11865d
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发表时间：
2015
期刊：
影响因子：
3.9
通讯作者：
Sun Yingchun
中科院分区：
文献类型：
--
作者：
Ma Jiani;Cui Jie;Han Yuanyuan;Jiang Wei;Sun Yingchun
采用格子Monte Carlo模拟方法研究了ABCA四嵌段共聚物在A选择性溶剂中的相行为。主要关注的是嵌段B和C（eBS和eCS）的疏溶剂相互作用对胶束形态的影响。三种ABCA四嵌段共聚物，即，考虑A2 B6 C6 A2、A2 B7 C5 A2和A2 B8 C4 A2四嵌段共聚物。给出了这三种四嵌段共聚物的相图，并讨论了它们与eCS的关系以及嵌段B和C之间的疏溶剂相互作用差（用r = eBS/eCS表示）。结果表明，r和eCS均能影响胶束的比表面积，导致ABCA四嵌段共聚物胶束的形态发生变化。此外，r可以改变胶束的疏溶剂链构象，从而影响胶束疏溶剂部分的微观结构。对于A2 B7 C5 A2和A2 B8 C4 A2四嵌段共聚物，得到了一些新的胶束形态，如弯曲的Janus带和片层，短Janus管和碗状半囊泡。有趣的是，在A2 B7 C5 A2和A2 B8 C4 A2四嵌段共聚物的相图中，具有Janus类疏溶剂部分的胶束类型是主要的胶束类型，这主要是由嵌段B和C之间的疏溶剂相互作用平衡引起的。此外，这些新的Janus型胶束的形成途径给出和讨论。
The phase behavior of the ABCA tetrablock copolymers in A-selective solvents is investigated using Lattice Monte Carlo simulation. The main focus is the effects of the solvophobic interactions of blocks B and C (eBS and eCS) on the micelle morphologies. Three kinds of ABCA tetrablock copolymers, i.e., A2B6C6A2, A2B7C5A2 and A2B8C4A2 tetrablock copolymers, are considered. Phase diagrams of these three tetrablock copolymers as a function of eCS and the solvophobic interaction difference between blocks B and C (which is measured by r = eBS/eCS) are given and discussed. It is found that r and eCS can both affect the specific surface area of micelles and lead to the morphological changes of ABCA tetrablock copolymer micelles. In addition, r can change the solvophobic chain conformation and hence affect the micro-structures of the solvophobic parts of the micelles. For A2B7C5A2 and A2B8C4A2 tetrablock copolymers, several novel micelle morphologies, such as the bended Janus ribbon and lamella, short Janus tube, and bowl-shaped semivesicle, are obtained. Interestingly, it is found that in the phase diagrams of A2B7C5A2 and A2B8C4A2 tetrablock copolymers, the micelle type with Janus-like solvophobic parts is the majority micelle type, which mainly results from the solvophobic interaction balance between blocks B and C. Moreover, the formation pathways for these novel Janus-type micelles are given and discussed.