Evaluation of surfactant-free stabilized vapor grown carbon fibers with ζ- potential and Raman spectroscopy

Commonly utilized mixed acids (H2SO4:HNO3 = 3:1, v/v) is utilized to investigate the covalent functionalization route of VGCF in this work. Sp2 hybrid C–C band of VGCF has been partly converted to sp3 hybrid by covalent treatment as confirmed by Raman and FT-IR spectroscopy results. And the converted C–C hybrid which results in the increased surface defects of fibers is identified to various hydrophilic groups. ζ-Potential and size distribution analysis of VGCF with/without treatment effectively explain that improved solubility is attributed to the enhanced electrostatic interaction between shortened VGCF collides and water. Finally, we give a proposal for the chemical functionlization route of VGCF based on the available characterization results.