In situ deposition of polythiophene nanoparticles on flexible transparent films: Effect of the process conditions

Polythiophene (PTh) was deposited as a thin film and nanoparticles on polyethylene naphthalate (PEN) films via ultrasonication or via magnetic stirring with or without a cationic (cetyltrimethylammonium bromide, CTAB) or non-ionic (Triton X-100) surfactant. The resulting conductive flexible films were characterized by UV-Vis spectroscopy, fluorescence spectrometry, field-emission scanning electron microscopy, contact angle measurements, the four-point-probe technique, X-ray diffraction, and cyclic voltammetry. The highest conductivity was obtained for PTh-CTAB nanoparticles, which had the most compact surface morphology among nanoparticles on PEN films. In general, the surface morphology, electrical conductivity, and whether PTh nanoparticles had been precipitated or deposited depended on the surfactant used, the surfactant/monomer ratio, the oxidant/monomer ratio, and the monomer concentration.