The influence of steam on the electrical properties of poly(3-alkylthiophenes) and their derivatives

The electrical properties of thin low and high molecular weight layers of poly(3-alkylthiophenes) (P3AT) and their chloro-, poly(3,beta'-chloroalkylo,4-chlorothiophenes) (P3AClT), and nitro-, poly(3-alkylo,4-nitrothiophenes) (P3ANO(2)T), derivatives for the application as detectors of steam, were studied. The kinetic of influence of steam on the d.c. conductivity of these polymers was studied too. It was found that d.c. conductivity of the studied polymers in the presence of steam increased and, during the removal, decreased. The increase of conductivity in the presence of steam is more evident in the chloro derivative cases. The layers of a polymer with a long alkyl side group, have a shorter response-time than those of polymers with a short one. The influence of steam on the d.c conductivity of these polymers is reversible. (C) 1997 Elsevier Science S.A.