The formation of different structures of poly(3-hexylthiophene) film on a patterned substrate by dip coating from aged solution.

Different local morphologies of poly(3-hexylthiophene) (P3HT, M(w) = 87,000 and 30,000-40,000 g mol(- 1)) are grown on a patterned substrate, which is composed of octadecyltrichlorosilane (OTS area) stripes on a silicon wafer (SiO(x) area), via dip coating from the aged solutions. Bundles of P3HT (M(w) = 87,000 g mol(- 1)) nanorods on the SiO(x) area and long nanofibrillar crystals on the OTS area are generated simultaneously from the one-day-aged 1 mg ml(- 1) solution, while oriented P3HT (M(w) = 30,000-40,000 g mol(- 1)) nanofibrillar crystals parallel to the long axis of the OTS pattern form on the OTS area from the seven-days-aged solution (1 mg ml(- 1)). Different dimensional sizes of the P3HT aggregate in the toluene solution upon aging and the flow of the solution from SiO(x) to the OTS area, on which the receding contact angle is larger than that on the SiO(x) area, determines the local structures of the P3HT film on the patterned substrate.