writer：Yingying Wang, Jie Cui, Yuanyuan Han, Wei Jiang
keywords：巨型表面活性剂, 纳米粒子, 嵌段共聚物, 链构型, 相行为, 自洽场理论
source：期刊
specific source：Langmuir, 2019, 35(2), 468-477
Issue time：2019年

摘要：采用自洽场理论与密度泛函理论相结合，研究了由单个AB两嵌段共聚物链单端连接纳米粒子（NP）构成的巨型表面活性剂的相行为。通过改变NP在双嵌段共聚物链上的位置，构建了三种不同链构型的巨型表面活性剂。模拟结果表明，NP的引入可诱导原本无序的AB两嵌段共聚物发生相分离，并构建了以A嵌段链长比和A嵌段与NP间吸引力为变量的三种巨型表面活性剂体系相图。当NP从B嵌段末端移至AB连接点再移至A嵌段末端时，体系构象熵逐渐降低，导致相行为显著不同。NP连接在B嵌段末端时，巨型表面活性剂体系相图中相分离区域最小，所得有序结构特征尺寸最小；而NP连接在A嵌段末端时，相分离区域最大，有序结构特征尺寸也最大。此外，三种体系中NPs在微相分离畴内的分布均可通过改变A嵌段链长比或A嵌段与NP间吸引力进行调控。这些发现为实验中制备形貌可控、特征尺寸理想、NP分布精确的聚合物-纳米粒子复合材料提供了指导。

Abstract：The phase behaviors of the giant surfactant constructed from a nanoparticle (NP) monotethered by a single AB diblock copolymer chain were investigated by combining self-consistent field theory and density functional theory. Three types of giant surfactants with different chain architectures were constructed via changing the location of NP on the diblock copolymer chain. The simulation results show that the introduction of the NP can induce phase separation of the originally disordered AB diblock copolymers, and phase diagrams as a function of the chain length ratio of A block and the attraction between A block and NP were constructed for the three giant surfactant systems. Via changing the location of NP from the end of B block to the AB-junction point and to the end of A block, the conformational entropies of the systems gradually decrease, leading to a significant difference in phase behaviors. When the NP is tethered to the end of B block, the giant surfactant system has the smallest phase-separation region in the phase diagram, and the resulting ordered structures have the smallest feature sizes. However, when the NP is tethered to the end of A block, the giant surfactant system has the largest phase-separation region, as well as the largest feature sizes of ordered structures. Moreover, the distributions of the NPs within microphase-separated domain can be well tailored by changing the chain length ratio of A block or the attraction between A block and NP in all of the three giant surfactant systems.

论文链接：https://doi.org/10.1021/acs.langmuir.8b03756