Critical Coagulation Concentrations for Carbon Nanotubes in Nonaqueous Solvent

Critical coagulation concentrations for several inorganic and metallodendrimer coagulants have been determined for dispersion of single-walled carbon nanotubes in nonaqueous solvent. The behavior of the nanotubes is not consistent with previously reported coagulations from aqueous electrolytes and is not described using classical Derjaguin, Landau, Verwey, and Overbeek theory of lyophobic colloids. Nanoscale rigid dendrimers are studied as they interact and bind to the carbon nanotubes. With a diameter of 5.8 nm and a charge of +20, these metallodendrimers bind strongly and specifically to the nanotubes. Systematic studies of aggregating nanotubes and nanoparticles are required to more completely understand the complex interactions between the nanotubes and the matrix in which they are dispersed. Strategies for directed self-assembly of the nanotubes have implications for the potential three-dimensional nanomanufacturing of nanoscale sensors and actuators.