Carbon nanotube-directed polytetrafluoroethylene crystal growth via initiated chemical vapor deposition

Initiated chemical vapor deposition (iCVD) has been shown to be suitable for blanketing surfaces with thin polymer coatings of ≈1-2 nm and greater. In this work, iCVD coatings of polytetrafluoroethylene (PTFE) deposited on carbon nanotube (CNT)-based surfaces show CNT-templated PTFE single crystal growth. While the coating forms disoriented agglomerates when deposited on an amorphous carbon background, "shish-kebab" structures are observed when grown on single-walled carbon nanotubes (SWCNT) as well as CNT buckypaper. It is shown that the shish-kebab structure is composed of PTFE lamellae arranged with the chain backbones running parallel to the SWCNT axis. This result allows one to control not only the surface chemistry using PTFE but also the coating surface topology. Templated relief patterns of polytetrafluoroethylene can be obtained through polymerization of hexafluoropropylene oxide from the vapor phase. Using the initiated chemical vapor deposition technique, "shish-kebab" structures develop on carbon nanotube-based substrates.