Application of polyaniline dispersions by means of screen printing

Abstract

In the recent time, the printing of functional substances (e.g., conducting polymers, metal-particle composites, carbon black and graphene based materials, etc.) has become of large importance. The main reason is the establishment of so-called printed electronics, where such substances are applied and later form functional electronic devices (e.g., sensors, displays, photovoltaic cells, transistors, etc.). Polyaniline has been reported to be a very versatile conducting polymer. Therefore, its application in a formof functional coatings and thin layers is desired. Polyaniline can be prepared in the presence of water-soluble polymeric stabilizers [e.g., poly(N-vinylpyrrolidone)], so that stable colloidal dispersions are obtained after the synthesis based on the oxidation of aniline with ammonium peroxydisulfate. These dispersions must be further adjusted for the needs of printing. This work is focused on the application of polyaniline-based dispersions by means of screen-printing method. A screen-printable formulation of polyaniline-based dispersion was prepared and printed on Melinex® ST504 poly(ethylene terephthalate) substrate. The quality and functionality of the prepared layers was studied by means of common methods (electrical resistance measurement, profilometry, optical microscopy with image analysis, optical spectroscopy). The prepared polyaniline films were examined also by means of photoacoustics, where changes in the subsurface structure and thickness of the polyaniline layers could be observed. The influence of the printing parameters as well as the components of the prepared formulations on the resulting quality and functionality was investigated.