title: Architectural Effects on Solution Self-Assembly of Poly(3-hexylthiophene)-Based Graft Copolymers.
abstract: While solution assembly of conjugated block copolymers has been widely used to produce long 1-D nanowires (NWs), it remains a great challenge to provide a higher level of control over structure and function of the NWs. Herein, for the first time, we report the solution assembly of graft copolymers containing a conjugated polymer backbone in a selective solvent and demonstrate that their self-assembly behaviors can be manipulated by the molecular structures of the graft copolymers. A series of poly(3-hexylthiophene)-graft-poly(2-vinylpyridine) (P3HT-g-P2VP) copolymers was designed with two different architectural parameters: grafting fraction (fg) and molecular weight of P2VP chains (Mn,P2VP) on the P3HT backbone. Interestingly, crystallization of the P3HT-g-P2VP copolymers was systematically modulated by changes in fgand Mn,P2VP, thus allowing for control of the growth kinetics and curvatures of solution-assembled NWs. When Mn,P2VP(4.4 to 15.1 kg/mol) or fg(2.8 to 9.2%) of the P3HT-g-P2VP polymers was increased, the crystallinity of the copolymers was reduced significantly. Steric hindrance from the grafted P2VP chains apparently modified the growth of NWs, leading to shorter NWs with a greater degree of curvature for graft copolymers with more hindrance. Therefore, we envision that such conjugated chain-based graft copolymers can be versatile building blocks for producing NWs with controlled length and shape, which can be important for tailoring the optical and electrical properties of NW-based devices.
authors.affiliation: Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST) , Daejeon, 34141, Korea.
authors.forename: Youngkwon
authors.initials: Y
authors.lastname: Kim
authors.affiliation: Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST) , Daejeon, 34141, Korea.
authors.forename: Hyeong Jun
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST) , Daejeon, 34141, Korea.
authors.forename: Jin-Seong
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Department of Polymer Science and Engineering, University of Massachusetts , Amherst, Massachusetts 01003, United States.
authors.forename: Ryan C
authors.identifier: http://orcid.org/0000-0001-6483-2234
authors.initials: RC
authors.lastname: Hayward
authors.affiliation: Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST) , Daejeon, 34141, Korea.
authors.forename: Bumjoon J
authors.identifier: http://orcid.org/0000-0001-7783-9689
authors.initials: BJ
authors.lastname: Kim
keywords: controlled crystallinity; graft copolymers; poly(3-hexylthiophene)-based copolymers; semicrystalline polymer; solution assembled nanowires; solution self-assembly