Preparation and properties of multilayer poly(3,4-ethylenedioxythiophene) Langmuir-Blodgett film

Multilayer ultrathin film of poly(3,4-ethylene dioxythiophene) (PEDOT) was fabricated using a modified Langmuir-Blodgett (LB) method. The chemical polymerization of PEDOT occurred in the multilayer nanometer space of an as-prepared LB film by exposing the film to 3,4-ethylene dioxythiophene vapor. UV-Vis-near infrared absorption spectrum and Fourier-transform infrared spectrum techniques were applied to confirm the formation of the PEDOT ultrathin film. The results of atomic force microscopy investigation for the PEDOT LB film showed that the film surface consisted of small clusters having diameters ranging from 50 to 200 nm. X-ray photoelectron spectroscopy and secondary-ion mass spectrometry were employed to analyze the atomic composition of the PEDOT LB film and the location of the formed PEDOT. It was found that the atomic composition of the composite film was almost consistent with the theoretical value, and the PEDOT clusters were well located in different planes of the multilayer structure. The PEDOT LB film exhibited higher conductivity than conventional films and better doping/dedoping characteristics of conductivity. The sensitivity of the PEDOT LB film to NH3 and HCl gases was also discussed