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.

• Yoon-Jin Kim(Department of Materials Science and Engineering, Korea University)
• Yong-Kyun Jang(Department of Materials Science and Engineering, Korea University)
• Woo-Nyon Kim(Department of Chemical and Biological Engineering, Korea University)
• Min Park(Polymer Hybrid Center, Korea Institute of Science and Technology)
• Jun-Kyung Kim(Polymer Hybrid Center, Korea Institute of Science and Technology)
• Ho-Gyu Yoon(Department of Materials Science and Engineering, Korea University)