Solvent-free functionalization and transfer of aligned carbon nanotubes with vapor-deposited polymer nanocoatings

Abstract

We studied solvent-free, one-step functionalization of aligned multi-walled carbon nanotube (MWNTs) using initiated chemical vapor deposition. Aligned MWNTs with a variety of aspect ratios were uniformly functionalized with an epoxy polymer. The vapor deposition process allowed excellent retention of the nanotube alignment and control of the porosity of the resultant MWNT nanostructure. In addition, we transferred the functionalized MWNTs using a flip-over procedure and directly measured the mechanical properties of the transferred MWNTs using nanoindentation. The transferring process created a synergistic effect by crosslinking the polymer coatings sheathed around the aligned nanotubes and forming strong adhesion between the nanotubes and the target substrate. As a result, the transferred MWNTs demonstrated a nanoindentation hardness of 0.49 GPa and an elastic modulus of 25.8 GPa, while the pristine MWNTs collapsed during nanoindentation. The transferred MWNT nanostructure also demonstrated significantly enhanced stability towards wetting and drying. The combination of surface functionality, nanotube alignment, controlled porosity, and enhanced mechanical robustness in the MWNT nanostructures may greatly impact the fabrication of carbon nanotube devices.