中国物理B ›› 2015, Vol. 24 ›› Issue (4): 46402-046402.doi: 10.1088/1674-1056/24/4/046402

• CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES • 上一篇    下一篇

Self-assembly of lamella-forming diblock copolymers confined in nanochannels: Effect of confinement geometry

于彬a, 邓建华a, 王铮b, 李宝会b, 史安昌c   

  1. a Department of Physics and Materials Science, Tianjin Normal University, Tianjin 300387, China;
    b School of Physics, Key Laboratory of Functional Polymer Materials, Ministry of Education, Nankai University, and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300071, China;
    c Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
  • 收稿日期:2014-09-29 修回日期:2014-11-20 出版日期:2015-04-05 发布日期:2015-04-05
  • 基金资助:

    Project supported by the National Natural Science Foundation of China (Grant Nos. 11204215, 51302187, 20990234, 20925414, 21204040, and 91227121), the Natural Science Foundation of Tianjin City, China (Grant Nos. 12JCYBJC32500 and 14JCZDJC32100), the Program for Changjiang Scholars and Innovative Research Team in University (PCSIRT) (Grant No. IRT1257), and the 111 Project. A. C. Shi gratefully acknowledges the supports from the Natural Sciences and Engineering Research Council (NSERC) of Canada.

Self-assembly of lamella-forming diblock copolymers confined in nanochannels: Effect of confinement geometry

Yu Bin (于彬)a, Deng Jian-Hua (邓建华)a, Wang Zheng (王铮)b, Li Bao-Hui (李宝会)b, Shi An-Chang (史安昌)c   

  1. a Department of Physics and Materials Science, Tianjin Normal University, Tianjin 300387, China;
    b School of Physics, Key Laboratory of Functional Polymer Materials, Ministry of Education, Nankai University, and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300071, China;
    c Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
  • Received:2014-09-29 Revised:2014-11-20 Online:2015-04-05 Published:2015-04-05
  • Contact: Yu Bin, Li Bao-Hui E-mail:stevenyubin@163.com;baohui@nankai.edu.cn
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Grant Nos. 11204215, 51302187, 20990234, 20925414, 21204040, and 91227121), the Natural Science Foundation of Tianjin City, China (Grant Nos. 12JCYBJC32500 and 14JCZDJC32100), the Program for Changjiang Scholars and Innovative Research Team in University (PCSIRT) (Grant No. IRT1257), and the 111 Project. A. C. Shi gratefully acknowledges the supports from the Natural Sciences and Engineering Research Council (NSERC) of Canada.

摘要:

The self-assembly of symmetric diblock copolymers confined in the channels of variously shaped cross sections (regular triangles, squares, and ellipses) is investigated using a simulated annealing technique. In the bulk, the studied symmetric diblock copolymers form a lamellar structure with period LL. The geometry and surface property of the confining channels have a large effect on the self-assembled structures and the orientation of the lamellar structures. Stacked perpendicular lamellae with period LL are observed for neutral surfaces regardless of the channel shape and size, but each lamella is in the shape of the corresponding channel's cross section. In the case of triangle-shaped cross sections, stacked parallel lamellae are the majority morphologies for weakly selective surfaces, while morphologies including a triangular-prism-shaped B-cylinder and multiple tridentate lamellae are obtained for strongly selective surfaces. In the cases of square-shaped and ellipse-shaped cross sections, concentric lamellae are the signature morphology for strongly selective surfaces, whereas for weakly selective surfaces, stacked parallel lamellae, and several types of folding lamellae are obtained in the case of square-shaped cross sections, and stacked parallel lamellae are the majority morphologies in the case of ellipse-shaped cross sections when the length of the minor axis is commensurate with the bulk lamellar period. The mean-square end-to-end distance, the average contact number between different species and the surface concentration of the A-monomers are computed to elucidate the mechanisms of the formation of the different morphologies. It is found that the resulting morphology is a consequence of competition among the chain stretching, interfacial energy, and surface energy. Our results suggest that the self-assembled morphology and the orientation of lamellae can be manipulated by the shape, the size, and the surface property of the confining channels.

关键词: diblock copolymers, self-assembly, confinement geometry, phase behavior

Abstract:

The self-assembly of symmetric diblock copolymers confined in the channels of variously shaped cross sections (regular triangles, squares, and ellipses) is investigated using a simulated annealing technique. In the bulk, the studied symmetric diblock copolymers form a lamellar structure with period LL. The geometry and surface property of the confining channels have a large effect on the self-assembled structures and the orientation of the lamellar structures. Stacked perpendicular lamellae with period LL are observed for neutral surfaces regardless of the channel shape and size, but each lamella is in the shape of the corresponding channel's cross section. In the case of triangle-shaped cross sections, stacked parallel lamellae are the majority morphologies for weakly selective surfaces, while morphologies including a triangular-prism-shaped B-cylinder and multiple tridentate lamellae are obtained for strongly selective surfaces. In the cases of square-shaped and ellipse-shaped cross sections, concentric lamellae are the signature morphology for strongly selective surfaces, whereas for weakly selective surfaces, stacked parallel lamellae, and several types of folding lamellae are obtained in the case of square-shaped cross sections, and stacked parallel lamellae are the majority morphologies in the case of ellipse-shaped cross sections when the length of the minor axis is commensurate with the bulk lamellar period. The mean-square end-to-end distance, the average contact number between different species and the surface concentration of the A-monomers are computed to elucidate the mechanisms of the formation of the different morphologies. It is found that the resulting morphology is a consequence of competition among the chain stretching, interfacial energy, and surface energy. Our results suggest that the self-assembled morphology and the orientation of lamellae can be manipulated by the shape, the size, and the surface property of the confining channels.

Key words: diblock copolymers, self-assembly, confinement geometry, phase behavior

中图分类号:  (Phase separation and segregation in nanoscale systems)

  • 64.75.Jk
64.75.Yz (Self-assembly) 83.80.Uv (Block copolymers) 83.80.Sg (Polymer melts)