Utilizing polymers for shaping the interfacial behavior of carbon nanotubes

A major obstacle for utilization of carbon nanotubes is their tendency to bundle and pack into ropes that further entangle into networks, rendering the tubes insoluble in aqueous and organic liquids, and thus almost un-processable. As was shown recently, physically adsorbed block-copolymers may be used for exfoliating and dispersing carbon nanotubes in aqueous and organic media. In this approach entropic repulsion among polymeric layers attached to CNT induce steric repulsion among the polymer-decorated tubes. The tube-polymer interactions are relatively weak, do not depend on the detailed chemistry of the interface and their range is tuned by the molecular weight and density of the polymeric layers, rather than by the chemical composition of the monomers. Combining theoretical modeling and experimental studies we demonstrate that this approach may be used for engineering the interfacial behavior of carbon nanotubes in a variety of systems.