SHORT-RANGE ORDER IN AMORPHOUS POLY(DECYLTHIOPHENES) - A TEMPERATURE-DEPENDENCE STUDY

X-ray diffraction studies have been carried out at various temperature s (300, 200, 100 and 15 K) for poly(3-decylthiophene) (PDT) and poly(4 ,4'-didecyl-2,2'-bithiophene) (PDDBT), both pristine and doped with Fe Cl4-. Because of the low crystallinity of all samples, especially for PDDBT, particular attention has been paid to the amorphous component o f diffractograms obtained. The temperature dependence of the diffracti on spectra gives strong evidence for structural transformation occurri ng between 300 and 200 K. This transformation is associated with the l owering of the mean intermolecular distance in the polymer, and it is visible both in the amorphous and crystalline components of the diffra ction patterns.