AFRL Reaches a Milestone with Vapor-grown Carbon Nanofibers

Applications

• Military and Commercial Significance:
• Nanotechnology provides unique opportunities to create and exploit revolutionary material combinations that scientists can use to circumvent classic material performance trade-offs. Such combinations can synergistically enable new properties only when the materials’ morphology (e.g., length scale) and the fundamental physics associated with the property coincide on the nanoscale.
• CNFs are nanoscale cylinders of graphitic carbon with a high aspect ratio (the ratio of length to diameter). A CNF is generally composed of two phases of carbon. The catalytic phase is formed by the catalytic action of the metal seed particle from which the CNF grows. This phase tends to consist of well-ordered, graphitelike planes of carbon atoms; however, these carbon planes are slightly curved to form
• a cylindrical material rather than a sheet. The deposited phase is the result of carbon CVD on top of the catalytic phase.
• AFRL and Applied Sciences, Inc., worked under a Small Business Innovation Research (SBIR) contract and
• reached a milestone by producing a longer vapor-grown carbon nanofiber (CNF) with a constant diameter
• of ~150 nm. The nanofibers can improve heat distortion temperatures and increase electromagnetic
• shielding. The long-fiber development also enables production of freestanding paperlike sheets, which
• are useful for several military and commercial applications. Examples of commercial applications include
• cell phone shielding, lightning strike protection, and electrostatic discharging materials.