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Title
Japanese:Long-Range Ordered Lamellar Formation with Lower Molecular Weight PS-PMMA Block Copolymers: Significant Effects of Discrete Oligopeptides at the Junction 
English:Long-Range Ordered Lamellar Formation with Lower Molecular Weight PS-PMMA Block Copolymers: Significant Effects of Discrete Oligopeptides at the Junction 
Author
Japanese: Tomoka Yoshimura, Tomofumi Morishita, Yoshihiro Agata, Kodai Nagashima, Kevin Wylie, Yuta Nabae, Teruaki Hayakawa, Makoto Ouchi.  
English: Tomoka Yoshimura, Tomofumi Morishita, Yoshihiro Agata, Kodai Nagashima, Kevin Wylie, Yuta Nabae, Teruaki Hayakawa, Makoto Ouchi.  
Language English 
Journal/Book name
Japanese:Macromolecules 
English:Macromolecules 
Volume, Number, Page Vol. 55    No. 6    pp. 2148-2159
Published date Feb. 17, 2022 
Publisher
Japanese:American Chemical Society 
English:American Chemical Society 
Conference name
Japanese: 
English: 
Conference site
Japanese: 
English: 
Official URL https://doi.org/10.1021/acs.macromol.1c02569
 
DOI https://doi.org/10.1021/acs.macromol.1c02569
Abstract We achieved the long-range ordered lamellar formation through phase separation of PS-PMMA block copolymers having low number-averaged degrees of polymerization (DPn,PS = 79 and DPn,PMMA = 107) by introduction of a discrete oligopeptide comprising several amino acids at the junction. A series of block copolymers carrying different amino acid sequence patterns were precisely synthesized, while the molecular weights of the two polymer segments were fixed. In particular, an amine-terminated polystyrene (PS) underwent an iterative amidation/deprotection with Boc-protected amino acids, followed by the reaction with an active ester-terminated poly(methyl methacrylate) (PMMA). The SAXS profiles of thus-obtained block copolymers depended on the oligopeptide structure at the junction. Consequently, the block copolymer carrying six amino acid units in the hexFFFFhex (hex: aminohexanoic acid; F: phenylalanine) sequence afforded the periodic lamella structure as supported by SAXS and TEM despite having a much lower molecular weight than the lowest value for the phase separation of unmodified PS-PMMA block copolymer predicted by Flory窶滴uggins theory. The specific phase separation behavior was further examined by DSC analyses, comparing the block copolymers with different amino acid sequences and the oligopeptide-ended PSs.

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