The effects of compositions, interaction parameters, and number of blocks on the self-assembly of nonfrustrated ABCBA linear pentablock terpolymer melts are investigated and compared with the corresponding ABC linear triblock terpolymers using the self-consistent field theory. For the case of symmetric interaction parameters (χ_ABN = χ_BCN) and majority B-blocks, both ABC triblocks and ABCBA pentablocks can form intriguing A- and C-domains embedded in the B-matrix. While these morphologies persist in the ABC systems when the segregation strength is decreased, the A blocks tend to mix with the B blocks in the ABCBA pentablocks due to the chain topology, resulting in the formation of C-domains embedded in the AB-mixed matrix. Different phase behavior is observed for the case of asymmetric interaction parameters (χ_ABN < χ_BCN). Aside from the core–shell type structures, a number of morphologies arise due to the separation between C and AB-mixed domains in ABCBA pentablock copolymers. The theoretical results not only capture the self-assembling behavior of poly(isoprene-b-styrene-b-ethylene oxide-b-styrene-b-isoprene) pentablocks, but also provide concrete suggestions for designing diverse microstructures in the linear ABC-type terpolymers.

中文翻译：

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非受阻 ABCBA 线性五嵌段三元共聚物的自组装

研究了组成、相互作用参数和嵌段数量对非受阻 ABCBA 线性五嵌段三元共聚物熔体自组装的影响，并使用自洽场理论与相应的 ABC 线性三嵌段三元共聚物进行了比较。对于对称相互作用参数的情况 ( χ _AB N = χ _BC N) 和多数 B 嵌段，ABC 三嵌段和 ABCBA 五嵌段都可以形成嵌入 B 矩阵的有趣的 A 和 C 域。虽然当分离强度降低时这些形态在 ABC 系统中持续存在，但由于链拓扑结构，A 嵌段倾向于与 ABCBA 五嵌段中的 B 嵌段混合，导致形成嵌入 AB 混合基质中的 C 域. 对于不对称相互作用参数（χ _AB N < χ _BC N）的情况，观察到不同的相行为。除了核壳型结构外，由于 ABCBA 五嵌段共聚物中 C 和 AB 混合域之间的分离，还会出现许多形态。理论结果不仅捕获了聚（异戊二烯-b -苯乙烯- b -乙烯氧化物- b -苯乙烯- b -异戊二烯）五嵌段，而且还提供用于设计在直线ABC型三元共聚物的微结构不同的具体建议。