Carbon nanofibers: A novel nanofiller for nanofluid applications

Carbon nanofibers (CNF), which is considered as the novel nanofiller, were used to prepare nanofluids. A low temperature oxygen plasma treatment was performed to modify the CNF surface. The plasma-treated CNFs (TCNF) were introduced into distilled water and ultrasonicated to form a well-dispersed suspension medium. The oxygen content of the TCNFs was enhanced with increasing plasma-treatment time. Together with the change of surface functionality, the plasma treatment of CNFs provided morphological advantages for the efficient dispersion of the CNF-water nanofluid. Thermogravimetric analysis was carried out to investigate the thermal degradation behavior of the CNFs. The surface functionality of the CNFs was confirmed by zeta-potential measurements. The surface defects of single CNFs were reduced due to the etching effect of plasma treatment. Results show that the herringbone-type CNFs act as a novel nanofiller and an excellent substitute for CNTs in nanofluid applications.