Controlled synthesis and fluorescent properties of poly(9-(4-vinylbenzyl)-9H-carbazole) via nitroxide-mediated living free-radical polymerization

The functional polymer containing carbazole unit, [(poly(9-(4-vinylbenzyl)-9H-carbazole) (PVBK)], was successfully prepared via nitroxide-mediated living free-radical polymerization of 9-(4-vinylbenzyl)-9H-carbazole (VBK). The controlled features of the polymerization were confirmed by the linear increase in the molecular weight with the monomer conversion while keeping the relative narrow molecular weight distribution (M-w/M-n <= 1.51), and successful chain extension with styrene. The resulting polymer absorbed light in the 305355 nm range and exhibited fluorescent emission at 350 nm. The fluorescent intensity of the polymer was lower than that of monomer and was affected by the properties of the different solvents, which decreased in the following order: DMF > THF > CHCl3 at the same concentration of carbazole units. The fluorescence intensity of the polymer was apparently influenced by chromophore concentration, and the maximum value was obtained when the carbazole unit concentration was around 8 x 10(-5) mol/L Moreover, it was shown that the strong fluorescence of PVBK can be quenched by methyl acrylate (MA). (C) 2008 Elsevier Ltd. All rights reserved.