Carbon nanotube (CNT) and cellulose composites were made using either long-fiber or short-fiber cellulose varieties in order to obtain bulk-conductive paper samples. From the mechanical and spatial homogeneity points of view, a 1:1 blend of both cellulose presented the best results for a fixed nanotube proportion. A combined X-ray diffractrometry and Raman scattering analysis confirmed the nanotube incorporation in the composite. By varying the CNT concentration, the sample resistivity was progressively decreased, reaching values as low as 4 × 10 −2 Ωm which is equivalent to 0.25 S/cm. The conduction mechanism of the composites is percolation-related and the critical CNT concentration is around 0.3%. An all-paper parallel-plate capacitor shows spatial homogeneity of the paper conductance (in terms of both fiber packing density and nanotube spatial distribution), and this seems to be key for achieving low-resistance conducting paper samples.
Metzger et al. (Sat,) studied this question.