Conductivity of inkjet-printed PEDOT:PSS-SWCNTs on uncoated papers

Abstract Poly(3,4-ethylenedioxythiopene): poly (styrene-sulfonate), or PEDOT:PSS, as well as singlewalled carbon nanotubes, were incorporated into an inkjet ink. Handsheets were prepared which contained varying amounts of TiO₂filler, internal sizing agent, fixation agent, and either softwood or hardwood kraft pulp. The ink was jetted onto the handsheets to form conductive layers with apparent conductivity as high as 0.018 S/cm on internally alkyketene dimer-sized softwood kraft handsheets with no other additives. Internal sizing increased conductivity at low filler loadings by preventing PEDOT:PSS from penetrating into the substrate, resulting in a conductive ink film on the surface of the sample. Unsized handsheets allowed more rapid absorption, and therefore deeper penetration, of the PEDOT:PSS ink, which resulted in a more diffuse conductive layer. The inclusion of a polyethyleneimine retention aid for TiO₂filler decreased conductivity significantly even in unfilled sheets by interaction with PSS^-counterions. A positively charged fixation agent, poly(diallyldimethylammonium) chloride, reduced PEDOT conductivity through the retention of nonconductive PSS^-anions.