Decomposition of Perfluorooctanoic Acid Photocatalyzed by TiO2: Chemical Modification of the Catalyst Surface Induced by Fluoride Ions.

17th ESFC – Paris 2013

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Perfluoropolyethers as hydrophobizing agents for fuel cells carbonaceous functional materials.

17th ESFC – Paris 2013

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Functionalization of multi-walled carbon nanotubes with perfluoropolyether peroxide to produce superhydrophobic properties

 

Author(s): TALAEEMASHHADI S.; SANSOTERA M.; GAMBAROTTI C.; FAMULARI A.; BIANCHI C. L.; GUARDA P. A.; NAVARRINI W.

Source: CARBON

Volume: 59 Pages: 150-159

DOI: 10.1016/j.carbon.2013.03.003 Published: AUG 2013

ABSTRACT:

Multi-walled carbon nanotubes (MWCNTs) have been functionalized through perfluoropolyether (PEPE) radicals obtained by thermal decomposition of linear PFPE peroxide. The reactivity of MWCNTs with PFPE peroxide has been compared with the direct fluorination of MWCNTs using elemental fluorine in mild conditions. The experimental results indicated that the functionalization with PFPE peroxide and the direct fluorination with elemental fluorine were suitable techniques to modify and control the physical-chemical properties of MWCNTs. After the introduction of PFPE chains on the MWCNT surface, the wettability of MWCNTs changed from hydrophilic to superhydrophobic, because the low surface energy properties of PFPE were transferred to the MWCNT surface. However, the linkage of PFPE chains weakly influenced the electrical properties of conductive MWCNTs. The amount of PFPE chains linked to the carbon nanotubes, the PFPE fluids obtained by homocoupling side-reactions and the decomposed portion of PFPE have been evaluated by mass balance. The modified MWCNTs have been characterized by X-ray photoelectron spectroscopy, thermal gravimetric analysis, X-ray diffraction, scanning electron microscopy, contact angle and surface area measurements. The effects of the chemical treatment on the conductive properties of MWCNTs have been studied by resistivity measurements at different applied pressures.

http://www.sciencedirect.com/science/article/pii/S0008622313002078

17th European Symposium on Fluorine Chemistry – July 21-25, 2013, Paris, France

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17th European Symposium on Fluorine Chemistry – Paris – July 21-25, 2013

Perfluoropolyethers as hydrophobizing agents for Fuel Cells carbonaceous functional materials

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RELATED POSTER

Fluoritech awarded for Best poster on Sustainability at 17th ESFC

During the 17th European Symposium on Fluorine Chemistry (ESFC) in Paris, the poster ”Decomposition of perfluorooctanoic Acid Photocatalyzed by Titanium Dioxide: Chemical Modification of the Catalyst Surface Induced by Fluoride Ions” with authors F. Persico, M. Sansotera, W. Navarrini, C.L. Bianchi, S. Gatto, C. Pirola, was awarded as Best Poster on Sustainability.

Recent developments in the chemistry of organic perfluoro hypofluorites.

Author(s): VENTURINI F., SANSOTERA M., NAVARRINI W.

Source: Journal of Fluorine Chemistry

Volume: 155 Pages: 2-20

DOI: 10.1016/j.jfluchem.2013.07.005 (2013)

 

ABSTRACT:

Recent findings in the synthesis of perfluoro-hypofluorites, their reactivity and their use in the preparation of important perfluoro monomers are herein summarized and analyzed. The experimental conditions to induce free radical or electrophilic reactivity as well as their use as initiation system in the oxidation and oxypolimerization of fluorinated olefins are also presented. Particular emphasis is dedicated to safety issues since organic hypofluorites have the tendency to self-decompose forming gaseous compounds.The hypofluorites considered in this review are: CF3OF, CF2(OF)2, CF3CF2OCF2OF, CF3OCF2CF2OCF2OF, CF3O(CF2O)nCF2OF, CF3OCF2CF2OF, (CF3)2CFOF (CF3)3COF, FS(O)2CF2CF2OF, CF3OCF2CF2CF2OF, cyclo-(CF2OCF2OCF)-CF2OF, (CF3)2N-CF2OF.

http://www.sciencedirect.com/science/article/pii/S0022113913002601

Advances in glass Microfabrication. Femtosecond laser irradiation followed by chemical etching.

Author(s): VENTURINI F., SANSOTERA M., OSELLAME R., CERULLO G., NAVARRINI W.

Source: Chimica Oggi – Chemistry Today.

Volume: 30 Pages: 10-13. December (2012).

ABSTRACT:

Femtosecond laser irradiation followed by chemical etching (F.L.I.C.E.) is an emerging technique for the fabrication of directly buried, three-dimensional microfluidic channels in silica. The procedure attested in literature, which has been widely studied in the past years, consists of irradiating a glass slab and subsequently apply a chemical etching step. The results obtained by different research groups vary widely. In this paper we present a review of the most recent advancements of this technique discussing several critical factors that affect the aspect ratio, the length and the etching speed of the microchannel.

http://www.teknoscienze.com/Articles/Chimica-Oggi-Chemistry-Today-Advances-in-glass-Microfabrication-Femtosecond-laser-irradiation.aspx#.UouCWycUlZM

Direct fluorination of carbon monoxide in microreactors.

Author(s): NAVARRINI W., VENTURINI, F., TORTELLI V., BASAK S., PIMPARKAR K. P., ADAMO A., JENSEN K. F. Source: Journal of Fluorine Chemistry. Volume: 142 Pages: 19-23. DOI: 10.1016/j.jfluchem.2012.06.006. Published: Oct (2012). ABSTRACT:

Many attempts to obtain a clean stream of COF2 have been carried out in the past by means of the direct fluorination of carbon monoxide with elemental fluorine or by electrochemical fluorination. The reaction is highly exothermic, therefore difficult to control. It can easily develop into a thermal runaway with a poor selectivity. We have successfully circumvented these critical issues by using a stainless steel parallel channel microreactor (surface/volume ratio approximate to 1 x 104 m(-1), residence time T approximate to 0.1 s) for the direct fluorination of carbon monoxide. Its performance in terms of operability and selectivity is compared to that of a standard reactor assembly, namely a fluorine burner reactor coupled with a water cooled heat exchanger. While the microreactor assembly succeeded to control the exothermic reaction, in the same experimental conditions the standard assembly reactor underwent serious corrosion issues that lead to nozzle meltdown lack of selectivity and consequent plant shutdowns. http://www.sciencedirect.com/science/article/pii/S0022113912001790

Micromanufacturing in Fused Silica via Femtosecond Laser Irradiation Followed by Gas-Phase Chemical Etching.

Author(s): VENTURINI F., SANSOTERA M., VAZQUEZ R. M., OSELLAME R., CERULLO G., NAVARRINI W.

Sources: Micromachines

Volume: 3 (4) Pages: 604-614.

DOI:10.3390/mi3040604.

Published: Sept (2012).

ABSTRACT:

Femtosecond laser irradiation followed by chemical etching (FLICE) with hydrogen fluoride (HF) is an emerging technique for the fabrication of directly buried, three-dimensional microfluidic channels in silica. The procedure, as described in literature, consists of irradiating a silica slab followed by chemical etching using hydrogen fluoride. With aqueous HF the etching process is diffusion-limited and is self-terminating, leading to maximum microchannel lengths of about 1.5 mm, while the use of low-pressure gaseous HF etchant can quickly produce 3 mm long channels with an aspect ratio (Length/Diameter) higher than 25. By utilizing this methodology the aspect ratio is not constant, but depends on the length of the channel. When the microchannel is short the aspect ratio increases quickly until it reaches a maximum length at around 1400 um hereafter the aspect ratio starts to decrease slowly. In this paper we present a variation of the low-pressure gaseous HF etching method, which is based on the dynamic displacement of the etchant. This method results in a 13% increase in the aspect ratio (L/D = 29) at the expense of a low etching speed (4 um/min).

SurfaceModification of Multi-Walled Carbon Nanotubes by Perfluoropolyether Peroxide.

International Conference on Diamond and Carbon Materials – Granada 2012

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Direct trifluoro-methoxylation of aromatics with perfluoro-methyl-hypofluorite.

Author(s): VENTURINI F., NAVARRINI W., FAMULARI A., SANSOTERA M., DARDANI P., TORTELLI V.

Source: Journal of Fluorine Chemistry.

Volume: 140 Pages: 43-48.

DOI: 10.1016/j.jfluchem.2012.04.008.

Published: Aug (2012).

ABSTRACT:

The reactivity of CF3OF (FM) has been widely studied especially in halogenated olefinic systems and its use in pharmaceutical synthesis as a mild radical and electrophilic fluorinating agent is well documented. On the other hand, the chemical behavior of the perfluoro-methyl-hypofluorite with aromatic substrates is much less studied. Up to now few and scattered data regarding its use as electrophilic fluorinating agent of variously substituted aromatic compounds are found in the literature. In this work the reactivity of CF3OF with simple electron rich and electron poor aromatics (alpha,alpha,alpha-trifluoro-toluene, toluene. benzene, chloro-benzene, methoxybenzene) has been investigated. The possibility of selectively bind the trifluoro-methoxy group (via radical mechanism) or the fluorine atom (via electrophilic addition) by varying the reaction conditions has been explored. In particular we have observed that the trifluoromethoxy free radical substitution can be the main synthetic pathway if the reaction is promoted by an independent and steady source of CF3O radical. http://www.sciencedirect.com/science/article/pii/S0022113912001145

20th International Symposium on Fluorine Chemistry – Kyoto (Japan) – July 22-27, 2012

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Superhydrophobic Properties and Electrical Performances of PFPE-Modified Carbonaceous Materials for PEM-FCs.

Fuel Cell Science & Technology – Berlin 2012

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Conductivity and superhydrophobic effect on PFPE-modified porous carbonaceous materials.

Author(s): SANSOTERA M., NAVARRINI W., GOLA M., DOTELLI G., STAMPINO P. G., BIANCHI C.L.

Source: INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

Volume: 37 Issue:7 Pages: 6277-6284

DOI: 10.1016/j.ijhydene.2011.07.041

ABSTRACT:

The thermal decomposition of a linear perfluoropolyether peroxide produced perfluoropolyether radicals that covalently bonded the unsaturated moieties on the surface of carbon black and carbon cloth. Measurements of contact angles demonstrated that water droplets were enduringly stable on the treated materials and that contact angle values were significantly high, exceeding the superhydrophobicity threshold. On the contrary, the droplets were adsorbed in few seconds by the native materials. Conductivity measurements showed that the covalent linkage of fluorinated chains weakly modified the electrical properties of the conductive carbonaceous materials, 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 X-ray photoelectron spectroscopy, resistivity measurements, scanning electron microscopy and surface area analysis. The modified carbon cloth was also tested out as gas-diffusion layer in a fuel cell and preliminary results were recorded.

http://www.sciencedirect.com/science/article/pii/S0360319911017010