Doped non-conjugated polymers with enhanced electrical conductivity .2.

Our previous investigations showed that polymers built up of short aromatic blocks and methylene chains became conductive upon doping with iodine. Now we prepared similar polymers with conjugated blocks consisting of different types and numbers of rings (benzene, thiophene, 1,3,4-oxadiazole) and methylene chains of different length. Despite being non-conjugated these polymers can be doped with iodine, resulting in an increase in electrical conductivity by up to six orders of magnitude. The colour turns black and a new absorption maximum, characteristic of I-3(-), appears in the UV spectrum at 370 nm. These results confirm our previous assumption that in such a type of polymers, some ordering of the aromatic blocks takes place. This evokes enhanced interaction equivalent to an extension of the conjugation, thus allowing doping, leading to conductivity increase.