Effect of amorphous fluorinated coatings on photocatalytic properties of anodized titanium surfaces.

Author(s): PERSICO F., SANSOTERA M., DIAMANTI M. V., MAGAGNIN L., VENTURINI F., NAVARRINI W.

Source: THIN SOLID FILMS

Volume: 545 Pages: 210-216

DOI:10.1016/j.tsf.2013.08.004

ABSTRACT:

The photocatalytic activity promoted by anodized titanium surfaces coated with different amorphous perfluoropolymers was evaluated. A copolymer between tetrafluoroethylene and perfluoro-4-trifluoromethoxy-1,3-dioxole and two perfluoropolyethers containing ammonium phosphate and triethoxysilane functionalities, respectively, were tested as coating materials. These coatings revealed good adhesion to the anodized titanium substrate and conferred to it both hydrophobicity and oleophobicity. The photocatalytic activity of the coating on anodized titanium was evaluated by monitoring the degradation of stearic acid via Infrared spectroscopy. The degradation rate of stearic acid was reduced but not set to zero by the presence of the fluorinated coatings, leading to the development of advanced functional coatings. The morphological variations of the coatings as a result of photocatalysis were also determined by atomic force microscopy.

http://www.sciencedirect.com/science/article/pii/S0040609013012960#

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

Electrodeposition of Fe-Ga thin films from eutectic-based ionic liquid.

Author(s): ZHAO F., FRANZ S., VICENZO A., BESTETTI M., VENTURINI F., CAVALLOTTI P. L.

Source: Electrochimica Acta.

doi:10.1016/j.electacta.2013.07.172 (2013).

ABSTRACT:

In the present work, a novel process for Fe-Ga thin films electrodeposition is addressed and the magnetic properties of the films are studied. The electrodeposition was carried out under ambient conditions using an ionic liquid electrolyte consisting of a mixture of choline chloride and ethylene glycol in the molar ratio 1:2, containing 0.3 M FeCl2 and 0.1 M GaCl3, either in the absence or in the presence of oxalic acid at 4 or 17 mM concentration. The effect of oxalic acid on the discharge reaction of the single ionic species Fe2+ and Ga3+ and on their codeposition was investigated by linear sweep voltammetry, suggesting a specific action of oxalic acid on the cathodic reduction of Ga3+ ionic species. Depending on deposition potential and oxalic acid concentration, alloy films with Ga content variable in the range up to about 20 at.% could be obtained. The Fe-Ga thin films showed a disordered body-cantered cubic phase (A2) with (110) preferred orientation and columnar microstructure, with a drastic change from pyramidal to granular surface morphology revealed raising the deposition potential. No superlattice reflections, indicating the formation of the D03 structure, were observed. A vibrating sample magnetometer was employed to measure hysteresis loops by applying longitudinal and transversal magnetic field on the Fe-Ga film plane. The saturation magnetization of as-deposited film reached 1.75 T for Fe83Ga17 thin films, confirming that good quality films were obtained. For the same alloy composition, the coercivity values were 67 Oe and 200 Oe, with applied field parallel and perpendicular to the film plane, respectively. http://www.sciencedirect.com/science/journal/aip/00134686

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

Serendipity and Murphy’s law are two sides of the same coin

Author(s): Navarrini, Walter.

Source: CHIMICA OGGI-CHEMISTRY TODAY Volume: 31 Issue: 4 Pages: 2-3 Published: JUL-AUG 2013

http://www.teknoscienze.com/Articles/Chimica-Oggi-Chemistry-Today-Serendipity-and-Murphy-rsquo-s-law-are-two-sides-of-the-same-coin.aspx#.Uo3g2ieiKP4

The environmental issue on CFCs in the optimization of the Italian system for WEEE recycling

Author(s): Sansotera, Maurizio; Gola, Massimo; Navarrini, Walter.

Source: CHIMICA OGGI-CHEMISTRY TODAY

Volume: 31 Issue: 3 Pages: 68-72

Published: MAY-JUN 2013

ABSTRACT:

The fast innovation cycle of electrical and electronic equipments (EEEs) pose the problem of a largewaste production. The correct disposal of WEEE is strictly needed because of their content in hazardous materials, like heavy metals and environmentally dangerous chemicals, which substances can be very dangerous both for the human health and the environment in which they are released. Chlorofluorocarbons (CFCs) are largely present in a particular class of WEEE, cooling and freezing equipment. CFCs are well recognized as ozone-depleting gases and can have an impact on the global warming higher than CO2. Being Northern Italy the primary source of CFC in Europe, the Italian WEEE Management System development has been investigated, with a focus on cooling and freezing equipment and related CFCs disposal.

http://www.teknoscienze.com/Articles/Chimica-Oggi-Chemistry-Today-The-environmental-issue-on-CFCs-in-the-optimization-of-the-Italian.aspx#.Uo3euSeiKP4

Italian WEEE management system and treatment of end-of-life cooling and freezing equipments for CFCs removal.

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

Source: Waste management (New York, N.Y.).

DOI: 10.1016/j.wasman.2013.03.012 (2013).

ABSTRACT:

This study presents and analyzes the data of the Italian system for take-back and recovery of waste electrical and electronic equipments (WEEEs) in the start-up period 2008-2010. The analysis was focused particularly on the data about the treatment of end-of-life cooling and freezing equipments. In fact, the wastes of cooling and freezing equipments have a high environmental impact. Indeed, in their compressor oil and insulation polyurethane (PU) foams chlorofluorocarbon (CFC) ozone-depleting gases are still present. In the period 2001-2004 Northern Italy resulted the main source in Europe of CFCs. The European Directive on WEEE management was enacted in 2002, but in Italy it was implemented by the legislative Decree in 2005 and it became operational in 2008. Actually, in 2008 the national WEEE Coordination Centre was founded in order to organize the WEEE pick-up process and to control collection, recovery and recycling targets. As a result, in 2010 the average WEEE collection per capita exceeded the threshold of more than 4 kg per inhabitant, as well as cooling and freezing appliances represented more than one fourth of the Italian WEEE collection stream. During the treatment of end-of-life cooling and freezing equipments, CFCs were recovered and disposed principally by burner methods. The analyses of defined specimens collected in the treatment facilities were standardized to reliably determine the amount of recovered CFCs. Samples of alkaline solid salt, alkaline saline solution, polyurethane matrix and compressor oil collected during the audit assessment procedure were analyzed and the results were discussed. In particular, the analysis of PU samples after the shredding and the warm pressing procedures measured a residual CFCs content around 500-1300 mg/kg of CFCs within the foam matrix. http://www.sciencedirect.com/science/article/pii/S0956053X13001542