In addition to developing catalysts and studying the catalysis process, we are also investigating ways to directly synthesize the carbon nanofibers into useful structures. Practically, this means that we can place the catalyst in a reaction chamber, and at the end of the reaction, we have an entirely fibrous, entirely carbon (< 1 % catalyst by mass), three-dimensionally tailored structure. This structure may be free-standing or it may be permanently contained within another component, such as tubing. Alternatively, materials may be contained within the carbon nanofibers grown to create a hybrid composite or other multi-component structures.
Referred to as the Constrained Formation of Fibrous Nanostructures (CoFFiN), this method can be modified to result in a variety of external geometries with additional control of the fiber characteristics possible. This truly multi-scale technique allows for a large degree of customization in a very simple, scalable package. Current capabilities allows us to produce carbon components with masses in grams and dimensions in centimeters within a few hours.
The properties of the carbon components are expected to make them suitable for applications in which carbon foams, activated carbon or carbon fiber is used. These nonwoven structures are in excess of 95% open volume and yet they are robust for handling. The close spacing of the nanofibers means that they can potentially filter out nanoscale contaminants, and their high surface area makes them competitive for catalyst support, super capacitor, molecular sieve and other surface sensitive applications. The primary advantage is the stability and usability of the material. A focused ion beam cross-section through the materials shown below. Property measurements and activation of the nanofibers are currently under way.
Want to see this stuff in action? Below are videos demonstrating the mechanical properties (and surprising robustness) of these materials.
Yes, it looks like a hockey puck. Fortunately, it works like one too!
This work is supported through the Civil, Mechanical and Manufacturing Innovation (CMMI) Division of NSF (Award # 1436444).
Constrained Nanofiber Publications:
- Mark A. Atwater, Roger J. Welsh, David S. Edwards. Direct synthesis of nanofibrous nonwoven carbon components: Initial Observations, Capabilities and Challenges. Journal of Micro- and Nano-Manufacturing. 4(4), p. 041004 (2016)
- Arash K Mousavi, Mark A Atwater, Behnam K Mousavi, Mohammad Jalalpour, Mahmoud Reda Taha, Zayd C Leseman. Mechanical and Electrical Characterization of Entangled Networks of Carbon Nanofibers. Materials; 7 (6), pp. 4845-4853 (2014)
- Mark A. Atwater, Arash K. Mousavi, Jonathan Phillips, Zayd C. Leseman. Direct Synthesis of Nanoscale Carbon Nonwovens by Catalytic Deposition. Carbon; 57 pp. 363-370 (2013)