Orientation of poly(3-alkylthiophene) on polyethylene crystals

Abstract

Poly(3-alkylthiophene)s (P3ATs) are conductive polymers soluble in many organic solvents. The number of carbon atoms (n) in the linear side chain in P3ATs used in this study was 6, 8, and 12. We concentrate on the result of P3HT (n=6), since similar results were obtained for the other two cases. In this paper we will report the molecular packing in P3HT whisker, and also the morphology and orientation of P3HT epitaxial growth on polyethylene (PE) crystals.P3HT whiskers were grown from a dilute solution of cyclohexanone while cooling the solution to room temperature. The color of the solution changed to red from yellow as the whiskers were formed. P3HT whiskers were also grown in cyclohexanone solution on PE single crystals mounted on a Cu grid supported by carbon film. Ultra-high molecular weight (UHMW) PE (Mw=4x106) gel film was uniaxially stretched (draw ratio=100). The drawn gel film was dipped into a xylene solution of P3HT at room temperature in order to crystallize the P3HT molecules onto the PE crystal. The samples were examined by a transmission electron microscope (TEM) at 80 kV.