Tailoring the physical characteristics of buckypaper via controlling the surfactant concentration

Abstract

Strategic improvement in mechanical load transfer ability of a randomly arranged carbon nanotube buckypaper by increasing nanotube interfaces comes at the cost of retarded increase in electrical counterpart on account of increased contact resistance. Various secondary routes, such as chemical functionalization, doping, densifying, etc., although have shown positive results, but still the physical attributes of buckypaper are not at par with the precedented knowledge of individual nanotubes. Herein, the mechanical and electrical properties of a buckypaper have been maneuvered desirably by controlling the amount of surfactant during its primary preparation steps. The prepared buckypapers showed high crystallinity and lower defects in their structures, evident from XRD and Raman spectra, respectively. The interplay of surfactant and physical parameters has been elicited by unbundling, and rebundling of nanotubes via surface coverage and micellar formation by surfactant molecules and has been duly correlated with the weakening of dispersion forces and decreased interface contact among nanotubes. Samples containing the lowest surfactant content exhibited the highest electrical conductivity of 91.74 S/cm, which was twice that of the buckypaper prepared with the highest surfactant content. Moreover, the control of surfactant concentration saw a 104% improvement in the tensile strength of buckypaper, as previously reported, which justifies that the results of this study are highly viable and crucial for the further development of buckypaper prospects.