16th European Symposium on Fluorine Chemistry – July 18 – 23, 2010, Ljubljana, Slovenia

16th European Symposium on Fluorine Chemistry – July 18 – 23, 2010, Ljubljana, Slovenia

FLUOROPOLYMER 2010 – June 13-16, 2010 – Meze, France

Linear and branched perfluoropolyether coatings on diamond-like carbon films: covalent linkage and physical deposition.

Author(s): NAVARRINI W., SANSOTERA M., VENTURINI F., BIANCHI C. L., GUARDA P. A., RESNATI G.

Source: Chimica Oggi – Chemistry Today.

Volume: 28 Pages: 24-27. Published: Apr (2010).

ABSTRACT:

The progresses in the magnetic media technology brought to the application of liquid lubricant films on diamond-like carbon (DLC) coatings. Hard surfaces are typically lubricated with fluorinated or perfluorinated organic compounds, such as perfluoropolyethers (PFPE). Many attempts have been done to obtain a stable layer of PFPE lubricant on the DLC surface by dip-coating or by vapour deposition so as to minimize any friction and wear . Diamond-like carbons are formed by an amorphous mixture of sp3 and sp2 hybridized carbon atoms with hydrogen atoms incorporated in the structure (a-C:H DLC). We have established a specific methodology for the straight-forward introduction of perfluorinated groups with carbon-carbon bond formation on a variety of unsaturated materials . Indeed, by using this methodology, perfluorinated radicals can directly bond to the sp2 sites of the DLC structure avoiding any spacer, that usually decreases both thermal and chemical stabilities of the resulting fluorinated layers .

19th International Symposium on Fluorine Chemistry – Jackson Hole (USA) – August 23-28, 2009

Functionalization of Carbonaceous Materials with High Fluorine Content Organic Peroxides

M. Sansotera ^a, W. Navarrini ^a, P. Metrangolo ^a, G. Resnati ^a, C. Bianchi ^b, A. Guarda ^c

^a Dip-CMIC ”Giulio Natta”, Politecnico di Milano, via Mancinelli 7, 20131 Milan, Italy;

^b Department of Physical Chemistry and Electrochemistry, University of Milan, via Golgi 19, 20133, Milan, Italy

^c R&D Centre, Solvay Solexis, viale Lombardia 20, 20021 Bollate (MI), Italy

E-mail: maurizio.sansotera@polimi.it

Perfluorodiacyl peroxides and perfluoropolyether peroxides (FOMBLIN peroxides) are suitable organic peroxides for direct linkage of perfluoroalkyl and perfluoropolyether chains on unsaturated substrates through a radical pathway. Highly graphitic carbon black and a-C:H diamond-like carbon are carbonaceous materials characterized by sp² hybridized carbon atoms in the structure. Consequently a chemical treatment with high fluorine content organic peroxides allows the introduction of fluorinated groups onto carbonaceous substrates with carbon-carbon bond formation [1]. Depending on the peroxide involved during the treatment, several fluorinated chains, i.e. perfluoroethyl, CF₃CF₂-, perfluoro-n-propyl, CF₃CF₂CF₂-, perfluoro-iso-propyl, (CF₃)₂CF-, and perfluoropolyether residual, has been covalently linked on the surface of such carbonaceous materials. Functionalization of carbon black transfers the typical hydrophobic properties of perfluorinated chains to the carbon black surface even preserving its conductive properties. This chemical treatment on diamond-like carbon films produces a covalently linked protective layers with the typical lubricant properties of perfluorinated compounds.

[1] Navarrini W., Sansotera M., Metrangolo P., Cavallotti P., Resnati G. WO 2009/019243 A1.