Microgels of poly(hydroxyethyl acrylate-co-coumaryl acrylate-co-octadecyl acrylate): photo-responsive release

초록

Poly(hydroxyethyl acrylate-co-coumaryl acrylate-co-octadecyl acrylate)s [P(HEA-CA-ODA)s], of which HEA/CA/ODA molar ratios were 98.6:0:1.4, 94.5:4.2:1.3, 90.9:7.6:1.4, and 82.5:16.2:1.3, were prepared by a free radical polymerization. CA residue is found to increase the amphiphilicity of the copolymer in the measurement of air/water interfacial activity. The CA residue of copolymers were readily dimerized and de-dimerized under the cyclic irradiation of UV light (365 nm and 254 nm). P(HEA-CA-ODA)s were assembled into microgels in distilled water possibly due to inter-/intramolecular hydrophobic interaction. A higher content of hydrophobic monomer (CA) led to a smaller microgel, possibly due to a short range hydrophobic interaction. The maximum Nile Red release degrees of the microgels in aqueous dimethylsulfoxide (DMSO) solution (10 %) were in the order of UV-untreated > UV (365 nm)-treated > UV (365 nm and 254 nm)-treated microgels possibly due to the CA dimerization and de-dimerization. The photo-sensitivity in the release was higher when the CA content of the copolymers was higher.

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