Synthesis of poly(styrene)-b-poly(2-vinyl pyridine) four-arm star block copolymers via ATRP and their self-assembly behaviors

• Published in: Polymer (Guilford) Vol. 213; p. 123212
• Main Authors: Hsu, Chia-Juei, Tu, Cheng-Wei, Huang, Yu-Wen, Kuo, Shiao-Wei, Lee, Rong-Ho, Liu, Yu-Ting, Hsueh, Han-Yu, Aimi, Junko, Huang, Chih-Feng
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 20.01.2021; Elsevier BV
• Subjects: Atom transfer radical polymerization; Atomic force microscopes; Atomic force microscopy; Block copolymers; Chains; Copolymers; Halides; Interaction parameters; Lamellae; Microscopes; Monomers; Morphology; poly(2-vinyl pyridine); poly(styrene); Polymer self-assembly; Polystyrene resins; Polyvinyl pyridine; Pyridines; Self-assembly; Small angle X ray scattering; Star block copolymers; Styrene; Styrenes; Substitution reactions; Transmission electron microscopy; X-ray scattering; Atom transfer radical polymerization; poly(2-vinyl pyridine); poly(styrene); Star block copolymers; Polymer self-assembly
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2020.123212

In this study, synthesis of poly (styrene)-b-poly (2-vinyl pyridine) four-arm star block copolymers ((PS-b-P2VP)4 sBCPs) possessing high interaction parameter (χ) feature was investigated. To obtain well-defined sBCPs, a challenge on ATRP of pyridine-containing monomers is foreseeable. We thus scrutinized the domino effect from PS macroinitiators (MIs) having different halogen chain ends (i.e., (PS–X)4, where X = Br/Cl) to the subsequent chain extensions. As evident from the model reactions of benzyl halides (BzX, where X = Br/Cl) and 2-methylpyridine (2 MP), the combination of BzCl and 2 MP can significantly suppress the substitution side reaction. Consequently, well-defined (PS-b-P2VP)4 sBCPs were obtained (Mn = ca. 58 k–82 k with PDI <1.5). From the analyses of small angle X-Ray scattering (SAXS), transmission electron microscopy (TEM), and atomic force microscope (AFM), self-assembly behaviors of the obtaining sBCPs were facilely observed due to the high χ feature, mainly including cylinder and lamellae morphologies, in nanoscale of approximately 30 nm. Well-defined 4-arm (PS-b-P2VP)4 sBCPs possessing high χ feature were synthesized via ATRP with distinctive conditions. The (PS-b-P2VP)4 sBCPs performed facilely self-assembly behaviors in nanoscale sizes. [Display omitted] •Domino effect from (PS-X)4 macroinitiators having different halogen chain ends (X= Br/Cl) to the subsequent chain extensions were studied and revealed the side reaction from the model reactions of benzyl halides (BzX; X = Br/Cl) and 2-methy lpyridine.•Well-defined 4-arm (PS-b-P2VP)4 star block copolymers (sBCPs) with high x feature were obtained (Mn = ca. 58 k-82 k with PDI <1.5).•From the analyses of SAXS, TEM, and AFM, self-assembly behaviors of the sBCPs were facilely observed, mainly including cylinder and lamellae morphologies (d-spacing = ca. 30 nm).