Tribological properties of fluorinated nanocarbons with different shape factors

The structural parameters of fluorinated nanocarbons presenting different shapes, i.e. spherical, tubular and discotic are investigated and correlated to their tribological properties. Different fluorination rates of graphitized carbon blacks (0D), carbon nanofibres (1D) and a mixture of carbon nanodiscs and nanocones (2D) were achieved under pure molecular fluorine gas flow (direct fluorination). Raman spectrometry, X-ray diffraction and 19F solid state nuclear magnetic resonance underline similar structure and nature of the CF bonds (covalent) for equivalent fluorine contents. In spite of the similarities of physical–chemical properties at equivalent fluorine contents, the tribological properties of the fluorinated nanocarbons differ. Those properties are discussed taking into account the role of the fluorine content and location of the fluorine atoms in the decrease of the interparticle interactions and in the cleavage of the external fluorocarbon layers to form the tribofilm. Finally, the effect of the shape is discussed.

Graphical abstractComparative study of the tribological properties of fluorinated nanocarbons with different dimensionalities (0D, 1D, 2D).Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Nanocarbonaceous materials with different shape factors were fluorinated using pure F2 gas with similar fluorine contents. ► Structure and CF bonding are similar at given fluorine content. ► The tribological properties of the fluorinated nanocarbons have been investigated and compared according to the shape factor.