Phase behavior of α, ω-dihexyl- α-quaterthiophene and ordering on a textured substrate

Abstract

Ordering of α, ω-dihexyl- α-quaterthiophene (DH α4T) thin films on substrates including friction-transferred polytetrafluoroethylene (PTFE) is explored. DH α4T exhibits a high-temperature mesophase from 81 to 181 °C. Textural analysis reveals this phase to be a tilted, highly ordered smectic phase. Upon cooling from the isotropic melt, the smectic phase grows layer by layer on many surfaces. Smectic thin films grown on friction-transferred PTFE exhibit a high degree of alignment with edge dislocations being the primary defect. Upon crystallization from the mesophase, the material retains for the most part the order of the mesophase. Growth of the smectic phase on directional surfaces such as friction-transferred PTFE appears to be a route to control of surface ordering of DH α4T.