Covalent functionalization through pure molecular gaseous fluorination has been applied on carbon nanofibres. Nuclear magnetic resonance and thermal gravimetric analysis investigations have been performed on fluorinated carbon nanofibres in order to determine the chemical and thermal stability of the C-F bonding. The high covalency obtained allows no significant modification of the physicochemical nanostructure of fluorinated carbon nanofibres after sonification. Such modification of surface chemistry leads to a high increase in the limit concentration of dispersed carbon nanofibres in organic solvents without surfactant. An exciting maximum of 570 mg L-1 of fluorinated nanofibres can be homogeneously dispersed in N-methylpyrrolidone, whereas 310 mg L-1 is the maximum for non-fluorinated carbon nanofibres. In order to understand such dispersibility differences, Hildebrand and Hansen solubility theory has been used. (C) 2013 Elsevier Inc. All rights reserved.