Direct Filament Formation of Biological Carbon Nanotube Suspensions

In this study, aqueous carbon nanotube (CNT) suspensions were prepared using biological surfactant of sodium deoxycholate (NaDC). The influence of NaDC concentration on the NaDC self-association in water and the rheological responses of the NaDC-CNT-water system were investigated. It has been found that the yield stress of the suspension increased with NaDC concentration, which was strongly related to the NaDC self-association of lyotropic liquid crystals. Due to the enhanced rheological properties at high NaDC concentration (30%), it allowed the shear-induced filament formation in which the CNTs were aligned along to the shear direction. This filament formation may be attractive for transferring aligned CNTs on substrates in a controlled manner.