Fabrication of Large-scale Drop-cast Films of π-conjugated Polymers with Floating-film Transfer Method

Abstract

Large-scale drop-cast films of π-conjugated polymers such as polythiophene derivs. and polyfluorene-based copolymers were formed on a liq.-substrate with 1-step deposition of floating-film transfer method (FTM). Centimeter-scale uniform cast films could be obtained. Relative sharp vibronic structure was found in the absorption spectra of FTM films as compared to those in spin-coated ones. FTM provides concentrically oriented films of a polymer having thermotropic liq. crystal characteristics. Comparative study of AFM topog. with absorption spectra revealed that the origin of the optical anisotropic absorption was in the uniaxial orientation of nano-scale fibrils. This indicates that the oriented FTM films possess extremely large domains extended over 5 orders from micrometer to 10 cm scale. The findings represent that FTM is a simple and effective casting method to provide large-scale and uniform drop-cast films. [on SciFinder(R)]