Dispersion of the functionalized multiwalled nanotubes (MWNT) in the polyurethane (PU) matrix and DC conductivity of
the MWNT/PU composites are investigated with the oxidation conditions, the kind of surfactants and their content. First, the
most optimal surfactant type and its critical micelle concentration in the MWNT suspension are determined as a cationic
surfactant, benzalkonium chloride (BKC) of 0.6 wt.% to the MWNT content from DEA and FESEM results. All the MWNT
oxidized under several conditions are negatively charged and functionalized with carboxylic group, whereas the degree of
damage is different from oxidation conditions. In addition, each MWNT/PU composite derived from several oxidation
conditions shows different DC conductivity at a characteristic MWNT content. It is found that in order to enhance DC
conductivity of the polymeric composites containing the oxidized MWNT the better dispersion of MWNT should be obtained
by effective functionalities and surfactant adsorption with preserving the intrinsic geometry of pristine MWNT.