Synthesis and photophysical studies of new segmented conjugated polymers with bis-styrylarylene units

ALMASSIO, M. F.; DEL ROSSO, P. G.; SEIXAS DE MELO, J. SERGIO; GARAY, R. O.

Porto

Congreso; 10th National Meeting on Photochemistry; 2010

Sociedade Portuguesa de Química

Conjugated polymers have become one of the most extensively studied classes of materials for use in organic electro-optical devices.[1] Most electro-optically active polymers have aromatic p-electron systems in their structure. Another structural feature is the type of units that link the aromatic systems. In conjugated polymers the active units are linked by likewise unsaturated units. On the other hand, regularly segmented conjugated polymers have non interacting or weakly interacting active units along the main chain which are isolated by saturated spacers. When the spacer is reduced to a methylene unit, the contorted polymer main chain forms very stable amorphous morphologies, substantially hinders interactions between chromophores and promotes solubility.[2] A new series of segmented conjugated polymers with meta-linked bis-styrylarylene units (see Fig.) were synthesised using the Wittig-Horner reaction. 1H NMR, 13C NMR and GPC were performed to obtain the structural characterization. Polymers have very regular chemical structures with all-trans carbon-carbon double bonds, good to high molecular weights (15 kDa to 40 kDa) and good solubility despite the absence in their structure of solubilising long chains. Extensive spectroscopic and photophysical studies of four bis-styrylarylene and their model compounds were undertaken in solution (293K and 77K) and in thin films. The optical properties of samples were investigated using UV–visible absorption, steady state and time-resolved photoluminescence emission spectroscopies together with triplet-triplet absorpion spectra and measurements of quantum yields (fluorescente, intersystem crossing and singlet oxygen convertion).  [1] a) L. Akcelrud, Prog. Polym. Sci., 28, (2003), 875. b) C. J. Brabec, N. S. Sariciftci, J. C. Hummelen, Adv. Funct. Mater., 11, (2001), 15. c) A.A. Argun et al. Chem. Mater., 16, (2004), 4401. d) S.W. Thomas, G.D. Joly, T.M. Swager, Chem. Rev., 107, (2007), 1339.[2] P.G. Del Rosso, M.F. Almassio, P. Aramendia, S.S. Antollini, R.O. Garay. European Polymer Journal 43 (2007) 2584-2593.