Outermost surface microstructure of as-grown, heat-treated and partially oxidized carbon microcoils Original Research Article

To evaluate the outermost surface microstructure of as-grown, heat-treated and oxidized carbon microcoils, the effects of the reaction time and heat treatment in Ar on the as-grown carbon microcoils were examined using TG/DTA, Raman scattering and microscopic FT-IR analyses. The starting temperature of the weight loss of the as-grown carbon microcoils in air increased with increasing reaction time. The weak and/or shouldered G-band peak at about 1580 cm−1, derived from the graphitic layer, was observed in the case of the longer reaction time of the as-grown carbon microcoils and/or their heat treatment in Ar. Furthermore, the absorption band at about 1580–1590 cm−1, assigned to the aromatic CC stretching vibrations of the oxidized carbon microcoils, was stronger than that of the as-grown carbon microcoils. The strengthened CC stretching vibration and/or G-band peak suggested an increase of the graphitized moieties of the carbon microcoils. In other words, it is considered that the graphitization degree at the outermost surface microstructure of the carbon microcoils increased by long reaction time, heat treatment in Ar and/or oxidation treatment.