Installing a functional group into the inactive ω-chain end of PMMA and PS-b-PMMA by terminal-selective transesterification. Issue 24 (22nd May 2019)

• Record Type: Journal Article
• Authors: Yoshida, Kohei; Yamamoto, Takuya; Tajima, Kenji; Isono, Takuya; Satoh, Toshifumi
• Is Part Of: Polymer chemistry. Volume 10:Issue 24(2019)
• Page Start: 3390
• Page End: 3398
• Publication Date: 2019-05-22
• Subjects: Polymers -- Periodicals; Macromolecules -- Periodicals; Polymerization -- Periodicals; 547.705
• DOI: 10.1039/c9py00315k
• Languages: English
• ISSNs: 1759-9954

Abstract

Abstract : Various functional groups were incorporated into the inherently inactive ω-chain end of polymethacrylate-based polymers by terminal-selective transesterification. Abstract : Polystyrene- block -poly(methyl methacrylate) (PS- b -PMMA) has been widely used as a nanotemplate material for the block copolymer lithography. Thus, development of a simple method to functionalize the inherently inactive PS- b -PMMA is of considerable interest to expand its potential applications. Herein, we demonstrate that titanium alkoxide-catalyzed transesterification can be a versatile chain-end functionalization method for proton-terminated PS- b -PMMA. Starting from anionically synthesized PMMA and PS- b -PMMA, the ester-side chain of the MMA unit at the ω-chain end was selectively transesterified in the presence of various alcohols with the aid of the corresponding titanium alkoxides to yield the end-functionalized PMMAs and PS- b -PMMAs. A wide range of alcohols containing various functional groups ( e.g., alkyl chains, aromatic rings, and fluorocarbon chains) were utilized for terminal-selective transesterification. Clickable groups ( e.g., pentafluorobenzyl and azido) were also successfully incorporated into the ω-terminal MMA unit, which serves as the reactive site for further modification. Importantly, even the hydroxy-functionalized polymer poly(ethylene glycol) monomethyl ether could be used for the terminal-selective transesterification of PS- b -PMMA, yielding a polystyrene- block -poly(methyl methacrylate)- block -poly(ethylene glycol) triblock terpolymer. The present transesterification system can be a powerful tool for chain-end functionalization of the inactive chain-end of PS- b -PMMA, providing insight into the effect of the chain-end structure on microphase separation behavior.