Gels of carbon nanotubes and a nonionic surfactant and high-quality carbon nanotube films prepared by gel coating

Abstract

This paper reports gels of carbon nanotubes (CNTs) with a nonionic surfactant, polyoxyethylene(12) tridecyl ether (POETE), and high-quality CNT films prepared by gel coating. Mixtures of multi-walled CNTs (MWCNTs) and POETE that was a fluid at room temperature became gels after mechanical grinding. The heavily entangled MWCNTs debundled during the grinding and dispersed with fewer bundles in POETE. The mechanism for the gel formation was studied by the dynamic mechanical measurements and scanning electron microscopy. The results suggest that the formation of the CNT/POETE gel is the result of the physical-crosslinking CNT networks, mediated by the van der Waals interaction between CNTs and the nonionic surfactant. The CNT/POETE gels were electrically conductive and could be processed into conductive CNT films by coating the CNT/POETE gels on a substrate by a doctor blade and subsequent heating. POETE was removed during the heating, while the heating did not degrade the CNTs. The CNT films had a good adhesion to substrate.