Preparation and characterization of superhydrophobic conductive fluorinated carbon blacks.

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

Source: Carbon.

Volume: 48 Issue: 15 Pages: 4382-4390.

DOI: 10.1016/j.carbon.2010.07.052. Published: Dec. (2010).

ABSTRACT:

Superhydrophobic conductive carbon blacks were prepared by covalent bonding of perfluorocarbon and perfluoropolyether chains on the conductive carbon black surface. Perfluorodiacyl and perfluoropolyether peroxides were used as reagents for the chemical treatment. Their thermal decomposition produced respectively, perfluoroalkyl and perfluoropolyether radicals that directly bonded the polycyclic aromatic structure of carbon black surface. Measurements of contact angles with water on molded pellets made with carbon black powder demonstrated that water droplets were enduringly stable on the treated carbon blacks. Contact angle values were significantly high, exceeding the superhydrophobicity threshold. On the contrary, the droplets were adsorbed in few seconds by the native carbon black. Conductivity measurements showed that the covalent linkage of fluorinated chains weakly modified the electrical properties of the conductive carbon black, even if the surface properties changed so deeply. The relationship between the linkage of fluorinated chains and the variations of physical?chemical properties were studied combining electron spectroscopy, resistivity measurements, X-ray diffraction, scanning electron microscopy, surface area analysis and thermal gravimetric analysis. The superhydrophobic conductive carbon blacks were compared with a superhydrophobic carbon black obtained by direct fluorination of conductive carbon black with elemental fluorine, F2.

http://www.sciencedirect.com/science/article/pii/S0008622310005567

Process for Preparing Ionomeric Membranes

US Patent: 7704639 B2

Date: Apr. 27, 2010

Inventors: W. Navarrini, S. Panero, B. Scrosati, A. Sanguineti

US7704639B2 – PDF

Low surface energy coatings covalently bonded on diamond-like carbon films

Author(s):Navarrini, Walter; Bianchi, Claudia L.; Magagnin, Luca; Nobili, Luca; Carignano, Gabriella; Metrangolo, Pierangelo; Resnati, Giuseppe; Sansotera, Maurizio.

Source: DIAMOND AND RELATED MATERIALS

Volume: 19 Issue: 4 Pages: 336-341

DOI: 10.1016/j.diamond.2010.01.004 Published: APR 2010

ABSTRACT:

In the present work, a chemical treatment with perfluorinated peroxides is proposed to obtain protective layers covalently linked to a diamond-like carbon (DLC) surface. The lubricant properties of perfiuorinated compounds and the stability of the chemical modification of DLC surface simultaneously cooperate in this technical approach. Each fluorinated layer is deposed on an bare DLC surface by a dip coating application technique and the covalent linkage of the fluorinated layers is obtained by the thermal decomposition of the peroxidic moieties of the perfluorinated peroxides. Reactive perfluorinated radicals are generated close to the sp(2) sites of the DLC surface, allowing the formation of covalent bonds. The fluorinated peroxides used in this work belong to the class of the PIPE peroxides and to the class of the perfluorodiacyl (PFDA) peroxides. The effect of the fluorinated coatings on the DLC surface is studied using X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), with contact angle (CA) measurements and, in particular, the friction forces are evaluated by means of lateral force microscopy (LFM).

http://www.sciencedirect.com/science/article/pii/S0925963510000130

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 .

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

Author(s):Navarrini, Walter; Sansotera, Maurizio; Venturini, Francesco; Bianchi, Claudia L.; Guarda, Antonio;Resnati, Giuseppe.

Source: CHIMICA OGGI-CHEMISTRY TODAY

Volume: 28 Issue: 2 Pages: 24- Published: MAR-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 sp(3) and sp(2) 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 sp(2) sites of the DLC structure avoiding any spacer, that usually decreases both thermal and chemical stabilities of the resulting fluorinated layers.

The little, juvenile and aggressive “fluorine atom” is growing up

Author(s): Navarrini, Walter.

Source: CHIMICA OGGI-CHEMISTRY TODAY Volume: 28 Issue: 2 Pages: 2-2 Published: MAR-APR 2010

Nanostructured TiO2 modified by perfluoropolyethers: Gas phase photocatalytic activity

Author(s): Bianchi, Claudia L.; Ardizzone, Silvia; Cappelletti, Giuseppe; Cerrato, Giuseppina; Navarrini, Walter; Sansotera, Maurizio.

Source: JOURNAL OF MATERIALS RESEARCH

Volume: 25 Issue: 1 Special Issue: SI Pages: 96-103

DOI: 10.1557/JMR.2010.0008 Published: JAN 2010

ABSTRACT:

A high-molecular-weight perfluoropolyether (PFPE-YR) and a perfluoropolyether containing ammonium phosphate (PFPE-F10) have been evaluated as fluorinated coating for high-surface-area titanium oxides. Coated nano-TiO2 shows hydrophobic properties and excellent buoyancy on water. In addition to photoactivity toward the degradation of toluene in gas phase, specific trial analyses have been completed to estimate the modified titanium oxide features. Brunauer-Emmett-Teller (BET) analysis for the surface area determination, ultraviolet-visible spectroscopy (UV-Vis) for the material electronic band gap, high-resolution transmission electron microscopy (HRTEM), x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS) for the morphology, structure, and surface composition, respectively, and water contact angle and infrared (IR) analysis have been performed to estimate the wettability and stability of coated titanium.

http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=7938175

Highly Hydrophobic Carbon Black Obtained by Covalent Linkage of Perfluorocarbon and Perfluoropolyether Chains on the Carbon Surface

Author(s): Sansotera, Maurizio; Bianchi, Claudia L.; Lecardi, Giorgio; Marchionni, Giuseppe; Metrangolo, Pierangelo; Resnati, Giuseppe; Navarrini, Walter.

Source: CHEMISTRY OF MATERIALS

Volume: 21 Issue: 19 Pages: 4498-4504

DOI: 10.1021/cm901271q

Published: OCT 13 2009

ABSTRACT:

Perfluorocarbon chains, that is, perfluoroethyl, CF(3)CF(2)-, pernuoro-n-propyl, CF(3)CF(2)CF(2)-, perfluoro-iso-propyl, (CF(3))(2)CF-, and perfluoropolyether (PFPE) residues, were covalently bonded on the surface of a carbon black using perfluorodiacyl and PFPE peroxides. Thermal decomposition of the fluorinated peroxides allows the covalent linkage of fluorinated radicals to the polycyclic aromatic structure of the carbon black. Contact angle measurements in agreement with XPS data revealed a gradual enhancement of the water repellence with increasing fluorine content on the surface. When perfluoroalkyl chains were bonded to the carbon black the morphology and the surface areas of the modified carbonaceous materials were mostly retained as shown by BET and SEM analyses.

http://pubs.acs.org/doi/abs/10.1021/cm901271q

Novel perfluoropolyethers containing 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxole blocks: synthesis and characterization

Author(s): Avataneo, M.; Navarrini, W.; De Patto, U.; Marchionni, G.

Source: JOURNAL OF FLUORINE CHEMISTRY

Volume: 130 Issue: 10 Pages: 933-937

DOI: 10.1016/j.jfluchem.2009.07.007 Published: OCT 2009

ABSTRACT:

Peroxidic perfluoropolyethers (PFPEs) are industrial intermediates used by Solvay Solexis for the preparation of different classes of (per)fluoropolyethers (Fomblin (R), Galden (R), Solvera (R), Fluorolink (R)). The chemistry of these peroxidic compounds has been recently exploited for the synthesis of novel PFPE block copolymers. In the present work we report the synthesis, the structural and physical-chemical characterization of block copolymers obtained by the reaction of peroxidic PFPEs with 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxole, a cyclic homopolymerizable perfluoroolefin. These block copolymers combine the most attractive properties of the PFPEs, like the excellent lubrication, the high thermal stability and the optical transparency, with new specific properties which are related to the perfluorodioxolenic blocks.

http://www.sciencedirect.com/science/article/pii/S0022113909002036

Perfluoroalkylation of graphitic carbon black: synthesis and thermal properties.

Author(s): SANSOTERA M., VENTURINI F., BERETTA S., BASSI M., PASQUALI A., BIANCHI C. L., METRANGOLO P., RESNATI G., NAVARRINI W.

Source: Chimica Oggi – Chemistry Today.

Volume: 27 Pages: 56-59.

Published: Jun. (2009).

ABSTRACT:

Perfluorodiacyl peroxides are suitable tools for thecovalent linkage of fluorinated groups on substrates containing aromatic moieties. The thermal decomposition process of such fluorinated peroxides allows the covalent linkage of fluorinated radicals on the polycyclic aromatic structure of a graphitic carbon black. Depending on the perfluorodiacyl peroxide involved during the chemical treatment, several fluorinated chains, i.e. perfluoroethyl, CF3CF2-, perfluoro-n-propyl, CF3CF2CF2- and perfluoro- iso-propyl, (CF3)2CF-residues have been bonded covalently on the surface of a conductive carbon black. At the characteristic temperature of perfluorocarbons thermolysis (400 C), thermogravimetric analyses revealed weight loss in agreement with the fluorine contents on the modified carbon blacks.

Composition for Porous Materials

EP: 1580320 B1

Date: May 27, 2009

Inventor: W. Navarrini

EP1580320B1 – PDF

Fluorovinyl Ethers and Polymers Obtainable Therefrom

US Patent: 7534845 B2

Date: May 19, 2009

Inventor: W. Navarrini

US7534845B2 – PDF

FLUO 34-Synthesis of low Ostwald coefficient perfluorinated ethers by the exploit of perfluoroalkyl hypofluorites.

Author(s): Navarrini, Walter; Venturini, Francesco; Sansotera, Maurizio; Metrangolo, Pierangelo; Resnati, Giuseppe; Galimberti, Marco; Tortelli, Vito.

Source: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY

Volume: 236

Meeting Abstract: 34-FLUO Published: AUG 17 2008

ABSTRACT:

The addiction reaction of hypofluorite to halogenated olefins has been studied in the past. In our previous studies we have noticed that the concentration of hypofluorite in the reaction media is an important variable to control the course of the main reaction. This experimental approach allowed the identification of a straight and economical methodology for the preparation of highly pure perfluoroethers with low boiling point and low Ostwald coefficient. These perfluoroethers have been recently tested as fluids for the preparation of injectable microbubble compositions as contrast agents in diagnostic ultrasound imaging. In many ultrasounds imaging applications there is the need for more efficient contrast agents and efforts to develop suitable materials are ongoing.

Addition of perfluoroolefins to trifluoromethyl hypofluorite for the preparation of low molecular weight perfluorinated oxygen containing fluids kinetics and byproducts.

Author(s): VENTURINI F., METRANGOLO P., RESNATI G., NAVARRINI W., TORTELLI V.

Source: Chimica Oggi – Chemistry Today.

Volume: 26 Pages: 36-38. Published: Aug. (2008).

ABSTRACT:

The products deriving from the addition of CF2=CFOCF3 to CF3OF are proved to be low Ostwald coefficient fluids suitable for producing high stable micro bubbles that can be used as ultrasound imaging contrast agents. The standard gas-liquid fast radical chain reaction between trifluoromethyl hypofluorite CF3OF and reactive perfluoroolefins like CF2=CFOCF3produces oligomerization and dimerization byproducts. Therefore a purification procedure is needed in order to separate the low Ostwald coefficient products from the reaction mixture. Surprisingly we have found that the selectivity of the reaction can be increased by modifying the experimental reaction conditions adopted. This behaviour is an experimental evidence for the presence of two different reaction schemes that can be switched by tuning the hypofluorite concentration in the reaction media.

The use of perfluoroalkyl hypofluorites for an efficient synthesis of perfluorinated ethers characterized by low Ostwald coefficient.

Author(s): NAVARRINI W., VENTURINI F., SANSOTERA M., URSINI M., METRANGOLO P., RESNATI G., GALIMBERTI M., BARCHIESI E., DARDANI P.

Source: Journal of Fluorine Chemistry.

Volume: 129 Issue: 8 Pages: 680-685.

DOI: 10.1016/j.jfluchem.2008.05.018. Published: Aug. (2008).

ABSTRACT:

In the reaction between perfluoroolefins and perfluoroalkylhypofluorites the existence of two different free radical reaction mechanisms is demonstrated by the presence of characteristic byproducts. These kinetic schemes can be experimentally controlled by tuning the hypofluorite concentration in the reaction media. In particular, in the reactions between trifluoromethyl hypofluorite and highly reactive perfluoroolefins like CF2CFOCF3 and CF2CF2, the free radical oligomerization and dimerization products can be suppressed by utilizing the opportune experimental conditions. The pure perfluorinated ethers obtained, having low Ostwald coefficient, can be utilized as contrast agents for diagnostic ultrasound imaging injectable microbubbles composition.

http://www.sciencedirect.com/science/article/pii/S0022113908001486