Alternating Sequence Control for Carboxylic Acid and Hydroxy Pendant Groups by Controlled Radical Cyclopolymerization of a Divinyl Monomer Carrying a Cleavable Spacer. (20th October 2016)

• Record Type: Journal Article
• Authors: Ouchi, Makoto; Nakano, Marina; Nakanishi, Tomoya; Sawamoto, Mitsuo
• Is Part Of: Angewandte Chemie. Volume 128:Number 47(2016)
• Page Start: 14804
• Page End: 14809
• Publication Date: 2016-10-20
• Subjects: Cyclopolymerisationen -- Methacrylsäure -- Radikalische Polymerizationen -- Sequenzkontrolle -- Untere kritische Lösungstemperatur (LCST); Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201607169
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: By utilizing features of the hemiacetal ester (HAE) bond: easy formation from vinyl ether and carboxylic acid and easy cleavage into different functional groups (‐COOH and ‐OH), we achieved control of the alternating sequence of two functional pendant groups of a vinyl copolymer. Methacrylate‐ and acrylate‐based vinyl groups were connected through HAE bonds to prepare a cleavable divinyl monomer, which was cyclo‐polymerized under optimized conditions in a ruthenium‐catalyzed living radical polymerization. Subsequent cleavage of the HAE bonds in the resultant cyclo‐pendant led to a copolymer consisting of alternating methacrylic acid and 2‐hydroxyethyl acrylate units as analyzed by 13 C NMR spectroscopy. The alternating sequence of ‐COOH and ‐OH pendants specifically provided a lower critical solution temperature (LCST) in an ether solvent, which was not observed with the random copolymer of same composition ratio.