title: Reversible modulation in luminescence intensity of a single vesicle composed of diblock azo-copolymer and tris(dibenzoylmethanate)(phenanthroline)europium(III).
abstract: Tris(dibenzoylmethanate)(phenanthroline)europium(III)[Eu(DBM)(3)Phen]-doped amphiphilic vesicles were obtained by self-assembling of poly(N-isopropylacrylamide)-b-poly[6-[4-(4-methylphenyl-azo) phenoxy] hexylacrylate] (PNIPAM(83)-b-PAzoM(20)) in presence of Eu(DBM)(3)Phen in the mixed solvent of THF/H(2)O (50/50 vol.%). Their optical properties were studied by UV-vis and fluorescence spectroscopies. The UV-vis spectrum showed that the electronic transition bands of azobenzene and Eu(DBM)(3)Phen were overlapped at about 365 nm and the main peak of fluorescence emission band appeared at 612 nm. So the vesicles showed obvious red luminescence. It was found that the fluorescence intensity of a single Eu(DBM)(3)Phen-doped vesicle could be modulated by irradiation with UV and visible light due to the reversible trans-cis-trans photoisomerization reaction of azobenzene moiety. Possible energy allocation process for this property was discussed in details.
authors.affiliation: CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, Anhui Province, University of Science and Technology of China, Hefei, Anhui, PR China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Yan
authors.forename: Wei
authors.initials: W
authors.lastname: Su
authors.forename: Yilong
authors.initials: Y
authors.lastname: Chen
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Luo
authors.forename: Qijin
authors.initials: Q
authors.lastname: Zhang
mesh_terms: D000178:Acrylamides / Q000138:chemical synthesis / Q000737:chemistry; D001391:Azo Compounds / Q000737:chemistry*; D047188:Chalcones / Q000737:chemistry; D005063:Europium / Q000737:chemistry*; D008027:Light; D008081:Liposomes / Q000737:chemistry*; D049449:Luminescence; D008163:Luminescent Measurements; D008856:Microscopy, Fluorescence; D008863:Microspheres; D008954:Models, Biological; D009942:Organometallic Compounds / Q000737:chemistry*; D010618:Phenanthrolines / Q000737:chemistry*; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry; D014466:Ultraviolet Rays
chemical_list: D000178:Acrylamides; D001391:Azo Compounds; D047188:Chalcones; D008081:Liposomes; D009942:Organometallic Compounds; D010618:Phenanthrolines; D011108:Polymers; C517349:europium-tris(dibenzoylmethane)-1,10-phenanthroline; C538829:poly(N-isopropylacrylamide)-b-poly(6-(4-(4-methylphenyl-azo) phenoxy) hexylacrylate); D005063:Europium; C061481:dibenzoylmethane