Spectroscopic studies on conjugated polymers in channels: influence of polymer side-chain mesoporous length

The influence of mesoporous environment on the conjugated polymers was studied by UV-Vis absorption and Photoluminescence spectroscopy. The applied polymers were three novel poly(p-phenylenevinylene) derivatives (DDMA-PPV). These polymers have dibenzothiophen-5,5-dioxide units in their backbones, but are different from each other in the length of alkoxy side-chains. The polymers were incorporated into the mesoporous channels of SBA-15 by sorption from their dilute solutions. The confined polymers exhibited different trends in the shifts of the absorption onsets and the emission peaks depending on the length of the side-chains. The polymer with shorter side-chain showed red-shifts in both the absorption and emission spectra, whereas the polymer with longer side-chain showed blue-shifts. These phenomena were caused by the combined influences from the electronic confinement and the conformation distortion. Moreover, these trends were enhanced when the polymers were loaded in amine-modified SBA-15. (C) 2003 Published by Elsevier Ltd.