Highly conductive and uniform PEDOT on poly(acrylic acid-vinylbenzyl chloride) functionalized surfaces

This study demonstrates increasing the uniformity and conductivity of poly(3,4-ethylene dioxythiophene) (PEDOT) thin films synthesized by vapor phase polymerization (VPP) through the utilization of a thin interfacial prime layer on the substrate surface. The prime layer, which is a copolymer of acrylic acid (AA) and vinylbenzyl chloride (VBC), was coated on the substrate surface using initiated chemical vapor deposition (iCVD) method. FTIR and XPS were used to analyze the structure of as-deposited films. The use of P(AA-VBC) copolymer as a prime layer allowed uniform and complete coverage of the oxidant solution on the substrate surface due to the hydrophilic nature of the AA constituent. During the VPP, the existence of the chlorine ions originating from the VBC constituent allowed in-situ doping of the as-deposited polymer, which contributes to the increased uniformity and the conductivity. The experimental studies were carried out to show the increase in uniformity, conductivity and adherence of the as-deposited PEDOT film in the presence of the prime layer. There was nearly a 4-fold increase in the conductivity of as-deposited PEDOT in the presence of the prime layer, with measured conductivity uniformity as high as 96% over a 5×5 cm² glass surface.