Generation of carbon nanofilaments on carbon fibers at 550 °C

• Published in: Carbon (New York) 2009-11, Vol.47 (13), p.3071-3078
• Main Authors: Luhrs, Claudia C., Garcia, Daniel, Tehrani, Mehran, Al-Haik, Marwan, Taha, Mahmoud Reda, Phillips, Jonathan
• Format: Article
• Language: English
• Subjects: Catalysis; Chemistry; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; General and physical chemistry; Materials science; Physics; Specific materials; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/j.carbon.2009.07.019

Employing a relatively new method, in which carbon structures are grown from fuel rich combustion mixtures using palladium particles as catalyst, multi-scale diameter nanometer – micrometer filament structures were grown from ethylene/oxygen mixtures at 550 °C on commercial PAN micrometer carbon fibers. The filaments formed had a diameter roughly equal to the palladium particle size. At sufficiently high metal loadings (>0.05 wt.%) a bimodal catalyst size distribution formed, hence a bimodal filament size distribution was generated. Relative short, densely spaced nanofilaments (ca. 10 nm diameter), and a slightly less dense layer of larger (ca. 100 nm diameter) faster growing fibers (ca. 10 μm/h) were found to exist together to create a unique multi-scale structure. A protocol was developed such that only nano-scale fibers or a mixture of nano and sub-micron fibers could be produced. No large range order was evident in the filaments. This work demonstrates a unique ability to create a truly ’multi-scale’ carbon structure on the surface of carbon fibers. This fiber structure potentially can enhance composite material strength, ductility and energy absorption characteristics.