Fluorinated vinyl ether homopolymers and copolymers: Living cationic polymerization and temperature-induced solubility transitions in various organic solvents including perfluoro solvents

• Published in: Journal of polymer science. Part A, Polymer chemistry Vol. 49; no. 9; pp. 2051 - 2058
• Main Authors: Shimomoto, Hiroaki, Fukami, Dai, Kanaoka, Shokyoku, Aoshima, Sadahito
• Format: Journal Article
• Language: English
• Published: Wiley Subscription Services, Inc., A Wiley Company 01.05.2011
• Subjects: acetone; chloroform; composite polymers; fluorine; fluorocarbon polymers; gel chromatography; molecular weight; polymerization; separation; solubility; solvents; temperature; tetrahydrofuran; toluene
• ISSN: 0887-624X; 1099-0518
• DOI: 10.1002/pola.24634

Partially fluorinated poly(vinyl ether)s with C₄F₉ and C₆F₁₂H groups in the side chain were synthesized via living cationic polymerization in the presence of an added base in a fluorine-containing solvent, dichloropentafluoropropanes. For comparison, the polymerization of vinyl ether monomers with C₂F₅ and C₆F₁₃ groups and nonfluorinated monomers were also carried out. The characterization of the product polymers using size exclusion chromatography with a fluorinated solvent as an eluent indicated that all polymers had narrow molecular weight distributions (Mw/Mn ∼ 1.1). Interestingly, the moderately fluorinated polymers with C₄F₉ exhibited upper critical solution temperature-type phase separation in various organic solvents with wide-ranging polarities, whereas highly fluorinated polymers with C₆F₁₃ are insoluble in nonfluorinated solvents. Polymers with C₄F₉ groups exhibited temperature dependent solubility transitions not only in common organic solvents (e.g., toluene, chloroform, tetrahydrofuran, and acetone) but also in perfluoro solvents [e.g., perfluoro(methylcyclohexane) and perfluorodecalin]. On the other hand, the solubility of polymers with C₆F₁₂H showed completely different from that of polymers with C₆F₁₃, despite their similar fluorine content. In addition, various types of fluorinated block copolymers were prepared in a living manner. The block copolymers with a thermosensitive fluorinated segment underwent temperature-induced micellization and sol-gel transition in various organic solvents.