Structure and properties of 3-alkoxy substituted polythiophene synthesizedat low temperature

Ln order to get a better knowledge on the influence of the introduction of alkoxy group on the thermal and optical properties of the conducting polyth iophene derivatives, poly(3-alkoxythiophene)s have been chemically polymeri zed using iron (III) chloride as oxidizing agent under lower temperature an d controlled addition of monomer. The polymers so obtained have relatively higher molecular weight, less defects and increased crystallinity as compar ed with those produced at room temperature. Their X-ray diffraction pattern s support the stacking structure of polymer chain as proposed for poly(3-al kylthiophene). Their thermal stability and transition behavior are studied using TGA and MDSC techniques and compared with those of corresponding poly (3-alkylthiophene). The glass transition and the onset of decomposition tem perature of the polymer decrease with the increase of the side chain length and the glass transition is dependent on the flexibility of the side chain introduced. The extent of conjugation of these polymers are higher than th at of poly(3-alkylthiophene) and the polymers exhibit interesting fluoresce nce phenomena. Moreover, these polymers are photosensitive and the prelimin ary results of the interaction between the polymer and the light are also r eported. (C) 2000 Elsevier Science Ltd. All rights reserved.