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Photodependent release from poly(vinyl alcohol)/epoxypropoxy coumarin hydrogels
Author(s) -
Lee Mi Sun,
Kim JinChul
Publication year - 2011
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.35411
Subject(s) - vinyl alcohol , coumarin , self healing hydrogels , polymer chemistry , aqueous solution , molar ratio , polymer , residue (chemistry) , alcohol , nuclear chemistry , swelling , materials science , irradiation , chemistry , organic chemistry , catalysis , composite material , physics , nuclear physics
To obtain a photoresponsive hydrogel, poly(vinyl alcohol) (PVA) having coumarin residue as a pending group was crosslinked by photodimerizing the coumarin pendants. PVA having coumarin pendants was prepared by reacting the polymer with epoxypropoxy coumarin (EPC) in a strong alkali condition with EPC/PVA molar ratio of 200/1. According to the 1H NMR spectrum of PVA‐EPC conjugate, the molar ratio of EPC residue to PVA was about 4.3/1, indicating that EPC was attached to PVA every 444 repeating units of vinyl alcohol. An aqueous solution of PVA‐EPC (5%, w/v) became a semi‐solid hydrogel by the irradiation of a light (λ = 365 nm; 400 W) for 1 hr. The dimerization degree of EPC residues of the hydrogel decreased and increased in a periodical manner under the cyclic irradiation between two UV lights (λ = 365 nm and λ = 254 nm). The release of 5(6)‐carboxyfluorescein (CF) from PVA‐EPC hydrogel was significantly enhanced by the 5 min‐irradiation of λ = 254 nm (6 W), possibly due to the photodedimerization of EPC residues of the hydrogel. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012