Conductive paper through LbL multilayering with conductive polymer: dominant factors to increase electrical conductivity

A conductive paper was made of cellulose fibers with a multilayer of polyethyleneimine (PEI) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and the factors to increase the conductivity of the paper were investigated. The adsorption amount and the structure of PEI and PEDOT:PSS multilayer was changed by controlling salt concentration and the number of layers, and inter-contact degree of fibers was controlled by calendering. The adsorption behavior of the polyelectrolytes onto cellulose was evaluated using a quartz crystal microbalance with dissipation monitoring, and the adsorption amount was quantitatively analyzed through Kjeldahl nitrogen analysis and an Inductively Coupled Plasma Optical Emission Spectrometer. The conductivity of the resultant paper was in the range of 10⁻⁵–10⁻⁴ S/cm without loss of paper strength. The conductivity of the paper increased when the multilayer was formed at low salt concentration and the conductive paper was calendered. It appeared that electron transfer by increased contact between PEDOT:PSS improved the conductivity of the paper.