Wetting and print quality study of an inkjet-printed poly(3-hexylthiophene) on pigment coated papers

Wetting and printing properties of recently developed smooth multilayer coated papers suitable for printed functionality have been investigated. Spreading of a semiconducting polymer poly(3-hexylthiophene) (P3HT) dissolved in ortho-dichlorobenzene (o-DCB) was studied both by contact angle measurements (macro-scale drop) and inkjet printing experiments (micro-scale droplet). In addition, film formation and final print quality of inkjetted P3HT was analyzed by topographical, chemical and optical characterization. Results were compared to reference substrates, poly(ethylene terephthalate) (PET) plastic and atomically flat mica. Wetting rate of the macro-scale drop was strongly influenced by the magnitude of surface extremes (asperties). Maximal spreading of inkjet droplets was affected by roughness, surface energy, pore volume and geometry of the substrate. Both the film formation of successive printings and the final film quality were comparable for the paper substrates and the PET film. Therefore the multilayer coated paper can be used instead of plastic films to reduce environmental impact. For example, low-cost disposable electronics can thus be made recyclable.