π-Electronic soft materials based on graphitic nanostructures

This review focuses on our recent studies on the development of soft materials consisting of graphitic nanostructures. We found that single-walled carbon nanotubes, when suspended in imidazolium ion-based ionic liquids and ground in an agate mortar, form physical gels (bucky gels), where entangled nanotube bundles are exfoliated to give highly dispersed, much finer bundles. The use of polymerizable ionic liquids as the gelling media leads to the formation of highly electroconductive polymer/nanotube composites, which show a dramatic enhancement in mechanical properties. Bucky gels allow the fabrication of the first printable actuator that operates for a long time in air at low applied voltages. We also succeeded in the development of a new family of nanotubular graphite through self-assembly of amphiphilic hexabenzocoronene derivatives. The nanotube consists of a graphitic wall formed from a great number of pi-stacked hexabenzocoronene units, which provide a charge carrier transport pathway. Suitable chemical modifications of the amphiphile resulted in the formation of nanotubes with various interesting properties. Details of the design, properties, and scope of such pi-electronic soft nanomaterials are described herein.