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Counterintuitive Photomodulation of the Thermal Phase Transition of Poly(methoxy diethylene glycol acrylate) in Aqueous Solution by trans–cis Isomerization of Copolymerized Azobenzenes
Author(s) -
Miasnikova Anna,
BenítezMontoya C. Adrián,
Laschewsky André
Publication year - 2013
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201300203
Subject(s) - photoisomerization , lower critical solution temperature , polymer chemistry , copolymer , acrylate , chain transfer , monomer , diethylene glycol , azobenzene , isomerization , chemistry , polymerization , raft , photochemistry , polymer , ethylene glycol , radical polymerization , organic chemistry , catalysis
The non‐ionic monomer (methoxy diethylene glycol) acrylate is copolymerized with its azo‐dye‐functionalized acrylate analogue using reversible addition–fragmentation chain transfer (RAFT) polymerization. Copolymerization is increasingly difficult with increasing amounts of the azo‐dye‐bearing monomer. The resulting water‐soluble polymers are thermosensitive, exhibiting lower critical solution temperature (LCST) behavior, which can be modulated by the photoinduced trans–cis isomerization of the dye. While already small contents of the hydrophobic azobenzene group reduce the phase‐transition temperatures of the copolymers strongly, photoisomerization of the apolar trans ‐state to the more‐polar cis ‐state has only a small effect, and decreases rather than increases the cloud points.