Stable dispersion of single wall carbon nanotubes in polyimide: the role of noncovalent interactions

Single wall carbon nanotubes (SWNTs) have been dispersed in a nitrile functionalized polyimide matrix and the resulting composite shows excellent stability with respect to reaggregation of the nanotubes. This contrasts with the behaviour of structurally similar polyimides in which the dispersion is only stable for short periods of time. Shifts in certain characteristic FTIR and Raman peaks which indicate a charge transfer interaction between the nanotubes and polymer matrix are observed. A simple model for charge transfer stabilization is presented and shown to be consistent with the experimental observations.