The microphase-separating behaviors of two types of star-diblock copolymers （Ax）4（By）4 and （A^Bg）4 in thin films are studied using the simulation technique of dissipative particle dynamics. A variety of ordered ...The microphase-separating behaviors of two types of star-diblock copolymers （Ax）4（By）4 and （A^Bg）4 in thin films are studied using the simulation technique of dissipative particle dynamics. A variety of ordered mesostructures have been observed and the simulated phase diagrams show obvious symmetries for the （Ax）4（By）a films and asymmetries for the （AxBy）4 films, besides, it is easier for the （Ax）4（By）4 than for the （A^By）4 to carry out microphase separation under the same conditions, which has been recognized in bulk and can be ascribed to the structural difference between the two types of star copolymers. There are some correspondences between the mesostructures formed in the film and those formed in bulk at the same composition fraction. Decreasing the thickness of film and strengthening the A-B repulsion both help the mesostructures enhance the degree of order. Composition fraction dependences of the mean-square radius of gyration in the two types of star copolymer films are almost contrary, which can be attributed to the differences in their respective structures. These findings can provide a guide to designing novel microstructures involving star-diblock copolymers via geometrical confinement.展开更多
用自洽场理论方法(Self-consistent field theory,SCFT)计算了嵌段共聚物AB和三等臂星型均聚物A共混体系的微相形态.为了简化计算,着重讨论了固定嵌段共聚物本体的相形态(如层状相)时,所加入的均聚物的体积分数及均聚物与嵌段共聚物链...用自洽场理论方法(Self-consistent field theory,SCFT)计算了嵌段共聚物AB和三等臂星型均聚物A共混体系的微相形态.为了简化计算,着重讨论了固定嵌段共聚物本体的相形态(如层状相)时,所加入的均聚物的体积分数及均聚物与嵌段共聚物链长之比对体系相形态的影响;并结合体系的熵和相互作用能的变化,讨论了星型均聚物在体系微相结构中的分布.展开更多
文摘The microphase-separating behaviors of two types of star-diblock copolymers （Ax）4（By）4 and （A^Bg）4 in thin films are studied using the simulation technique of dissipative particle dynamics. A variety of ordered mesostructures have been observed and the simulated phase diagrams show obvious symmetries for the （Ax）4（By）a films and asymmetries for the （AxBy）4 films, besides, it is easier for the （Ax）4（By）4 than for the （A^By）4 to carry out microphase separation under the same conditions, which has been recognized in bulk and can be ascribed to the structural difference between the two types of star copolymers. There are some correspondences between the mesostructures formed in the film and those formed in bulk at the same composition fraction. Decreasing the thickness of film and strengthening the A-B repulsion both help the mesostructures enhance the degree of order. Composition fraction dependences of the mean-square radius of gyration in the two types of star copolymer films are almost contrary, which can be attributed to the differences in their respective structures. These findings can provide a guide to designing novel microstructures involving star-diblock copolymers via geometrical confinement.
文摘用自洽场理论方法(Self-consistent field theory,SCFT)计算了嵌段共聚物AB和三等臂星型均聚物A共混体系的微相形态.为了简化计算,着重讨论了固定嵌段共聚物本体的相形态(如层状相)时,所加入的均聚物的体积分数及均聚物与嵌段共聚物链长之比对体系相形态的影响;并结合体系的熵和相互作用能的变化,讨论了星型均聚物在体系微相结构中的分布.
