Fabrication of organogels composed from carbon nanotubes through a supramolecular approach

Abstract

A new organogelator, N,N′-bis (octadecyl)-L-(1-pyrenebutyric acid)-glutamic diamide (LPG), was designed and its interaction with pristine single-walled carbon nanotubes (SWNTs) in the gel state was investigated. It was found that LPG can form organogels with various kinds of organic solvents. Although SWNT itself is difficult to disperse into organic solvents, it can be well dispersed into LPG gel. The gelation process and the properties of the resulting nanocomposites were found to be closely related to the pyrene group in the gelator. The addition of SWNTs significantly decreased the critical gelation concentration of LPG, depressed the sol to gel transition temperature and prolonged the time required to form a gel. Rheological investigations of LPG organogels showed that the flow of nanocomposites became more resistant to the applied stress upon the incorporation of SWNTs. This happened presumably via effective dispersion of SWNTs into the LPG organogels through π–π interaction between the surface of SWNTs and the pyrene group of LPG. The textures of the nanocomposites were altered from layer structure to intertwined fibers upon the incorporation of SWNTs, which also supported the effective mixing of SWNTs into LPG organogels.