Author(s): Matthew Fogleman, Dylan Holmes
Mentor(s): Brian D. Jensen, Jared Bowden
Institution BYU
Carbon infiltrated carbon nanotubes (CICNTs) are nanostructures that have highly beneficial mechanical properties and potential applications in medical devices due to their antibacterial effects. CICNTs consist of carbon nanotubes (CNTs) that are infiltrated with carbon, enhancing their density and surface area as they coat a surface. This material is particularly effective in disrupting bacterial biofilms, since its rough surface texture reduces biofilm adhesion, while its individual nanotubes interact with bacterial cell walls to exert lethal mechanical stress. Recently, it was discovered that these effects are maximized when the CICNTs have a precise diameter of 150 nanometers. Synthesis of CICNTs involves positioning an iron-coated titanium sample square inside a quartz tube within a furnace apparatus. During the initial 1-minute growth phase, ethylene and hydrogen gases are introduced at a controlled flow rate. This is followed by an 8-minute infiltration phase which enables uniform carbon deposition, yielding CICNT structures well-suited for antibacterial applications. As such, nanotube diameter is a function of both flow rate and position within the furnace tube. For this project, CICNT samples were grown in various locations within the furnace and at different flow rates by a research team at BYU Idaho, then shipped to BYU in Provo for analysis. Here, a scanning electron microscope was used to produce images of each sample at 80,000x magnification, from which diameter measurements were gathered. Statistical analysis of these results indicates that CICNT diameter is closely related to the availability of growth gases, as nanotube size was positively correlated with both gas flow rate and distance within the furnace. Furthermore, CICNTs were consistently produced with the ideal diameter of 150 nanometers when samples were positioned 20 centimeters inside the furnace. Ultimately, these findings will allow research teams (such as those in Idaho) to produce CICNT surfaces with more precise control over nanotube diameters, accelerating the rate at which their antibacterial properties can be studied. Understanding the relationship between growth conditions and CICNT diameters is also an important precursory step to the mass-production of CICNT coatings for medical applications. As this research progresses, it will increase our ability to prevent infections associated with medical instruments, implants, and prosthetics.