TOWARDS A THEORETICAL DESIGN OF THERMOCHROMIC POLYTHIOPHENES

Ab initio calculations have been performed on several bithiophene deri vatives which are the building blocks of substituted polythiophenes in order to correlate their torsional potential energy curves with the t hermochromic properties of the parent polymers. It is found that the o ccurrence of thermochromism in polythiophenes can be related to the va lues of the energy barrier calculated for the dimer models. Moreover, trends in the thermally induced blue-shift observed with some polythio phene derivatives can be related to the difference in the torsional an gles between a co-planar conformation and the more stable conformation of the corresponding bithiophene moieties. (C) 1997 Elsevier Science B.V.