Polythiophene Langmuir-Blodgett films: How do they order?

Polythiophene Langmuir-Blodgett films do not appear to have a layer structure as evidenced by X-rays. Results in the literature imply an apparent layer structure for a mixture of a polythiophene and a fatty acid but the Bragg peaks obtained were identical to those given by the fatty acid alone. In order to understand this apparent anomaly we have studied films of a polythiophene having perfluorinated side chains. We obtained Z layers and the films were apparently of a high quality but still did not exhibit a layer structure, Atomic force microscopy (AFM) showed that a five-layer film had re-arranged into a network whose individual cells were typically 100 nm across, These materials thus tend to re-organise into a fibrous structure on a scale only observable by AFM, We also attempted to form a superlattice by dipping bilayers of mercury stearate alternating with monolayers of the polymer and obtained superlattice X-ray peaks but also Bragg peaks corresponding to the mercury stearate alone.