Study On Synthesis And Properties Of Modified Poly (N-isopropylacrylamide) Containing Europium

Firstly, poly(N-isopropylacrylamide) with terminal aromatic groups(Ar-PNIPAM) of varying hydrophobicity were synthesized by atom transfer radical polymerization(ATRP), using N-isopropylacrylamide as monomer and phenyl 2-chloropropionate, (4'-phenyl)phenyl 2-chloropropionate and (2',6'-diphenyl)phenyl 2-chloropropionate as initators. Secondly, by rare earth Europium(â…¢) ion(Eu(â…¢)) and a-thenoyl trifluoroacetone(TTA) coordinated with the Ar-PNIPAM, the Ar-PNIPAM-Eu(â…¢) and the Ar-PNIPAM-Eu(â…¢)-TTA complexes were prepared. Furthermore, the Ar-PNIPAM and the Europium(â…¢) complexes were investigated. The results can be found as follows:The polymerization kinetics showed a good controllability, and the molecular weights distribution was between 1.07 and 1.14. The Ar-PNIPAM and the resulting complexes showed thermosensitive property. The lower critical solution temperature(LCST) values of Ar-PNIPAM were 31.5℃,21.6℃and 21.0℃, compared with 32℃of PNIPAM. The drop of the LCSTs was owing to the effect of the different end hydrophobic groups. The LCST values of Ar-PNIPAM-Eu(â…¢) were 31.7℃,22.0℃and 21.2℃, while the LCST values of Ar-PNIPAM-Eu(â…¢)-TTA were 32.0℃,22.2℃and 21.8℃. The Ar-PNIPAM-Eu(â…¢) and the Ar-PNIPAM-Eu(â…¢)-TTA complexes all had excellent fluorescence performance. The fluorescence spectrum presented 5Doâ†'7FJ(J=0,1,2,3,4) characteristic emission of Europium(â…¢) in 613nm, and as the conjugate gradient of the different terminal hydrophobic aromatic groups of Ar-PNIPAM increasing, the fluorescence intensity of the complexes strengthened gradually.