Abstract
Novel statistic copolymers of dialkyl vinylphosphonates have been synthesized via rare earth metal-mediated group transfer polymerization using easily accessible tris(cyclopentadienyl)ytterbium. The copolymerization parameters have been determined by activity measurements showing the formation of almost perfectly random copolymers (r1, r2 ∼ 1). Thus, the polymerization rate of vinylphosphonate GTP is mainly limited by the steric demand of growing polymer chain end. The obtained copolymers of diethyl vinylphosphonate and dimethyl or di-n-propyl vinylphosphonate show thermoresponsive properties, i.e., exhibit a tunable lower critical solution temperature following a coil-globule transition mechanism, with cloud points between 5 and 92 C. Hereby, the LCST can be precisely adjusted by varying the comonomer composition and correlates linearly with the content of hydrophilic/hydrophobic comonomer. These thermoresponsive poly(vinylphosphonate) s, exhibiting a sharp and reversible phase transition, and minor environmental effects such as concentration and additives on their cloud point, are promising candidates in biomedical applications.
Original language | English |
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Pages (from-to) | 9751-9758 |
Number of pages | 8 |
Journal | Macromolecules |
Volume | 45 |
Issue number | 24 |
DOIs | |
State | Published - 21 Dec 2012 |