Personne : Laroche, Gaétan
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Laroche
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Gaétan
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Université Laval. Département de génie des mines, de la métallurgie et des matériaux
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ncf10316941
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Publication Accès libre Fourier-Transform infrared spectroscopy of ethyl lactate decomposition and thin-film coating in a filamentary and a glow dielectric barrier discharge(Wiley-VCH-Verl., 2021-07-05) Milaniak, Natalia; Laroche, Gaétan; Massines, FrançoiseGlow and filamentary regimes of atmospheric pressure plasma-enhanced chemical vapor deposition in a planar dielectric barrier discharge configuration were compared for thin-film deposition from ethyl lactate (EL). EL decomposition in the plasma phase and thin-film composition were both characterized by Fourier- transform infrared spectroscopy. EL chemical bonds' concentration along the gas flow decreases progressively in the glow dielectric barrier discharge (GDBD), whereas it drastically oscillates in the filamentary dielectric barrier discharge (FDBD), with values higher than that of the initial mixture. EL decomposition route depends on the discharge regime, as the decrease of the concentration of the different investigated bonds is different for an identical amount of energy provided to EL molecules. CO2 is systematically formed reaching concentrations of 25 and 40 ppm, respectively, in FDBD and GDBD.Publication Restreint Atmospheric-pressure plasma-enhanced chemical vapor deposition of nanocomposite thin films from ethyl lactate and silica nanoparticles(Weinheim Wiley-VCH-Verl., 2020-10-09) Milaniak, Natalia; Laroche, Gaétan; Massines, FrançoiseNanocomposite coatings are made by atmospheric-pressure plasma-enhanced chemical vapor deposition from ethyl lactate (EL) and silica nanoparticles (NPs) in a dielectric barrier discharge (DBD) using frequency-shift keying (FSK) to alternate between 1- and 15-kHz voltages. In situ plasma Fourier-transform infrared spectroscopy (FTIR) and thin film FTIR, scanning electron microscopy, atomic force microscopy, and profilometry show that (i) 1 kHz DBD mainly deposits NPs, 15 kHz only polymerizes EL; (ii) the EL polymerization rate is the same in FSK and continuous modes; (iii) despite the 50/50 contribution of both frequencies, the NP deposit is three times faster in FSK mode than in 1 kHz DBD and compared with 1 and 15 kHz coatings, in the nanocomposite, NP Si–O–Si and EL C═O bonds per unit length are equal to 68% and 34%, respectively. In situ FTIR detects SiO2 NPs, their functionalization, and the formation of CO2.Publication Accès libre A new approach for synthesizing plasmonic polymer nanocomposite thin films by combining a gold salt aerosol and an atmospheric pressure low-temperature plasma(2021-02-05) Nadal, Elie; Milaniak, Natalia; Laroche, Gaétan; Glenat, Hervé; Massines, FrançoiseThe proof of the concept of a new, onestep and safe by design process to synthesize metal-polymer nanocomposites thin films on a large surface is presented. It is based on the injection of an aerosol of a solution of metal (gold) salts dissolved in a polymerizable solvent (isopropanol) into an argon atmospheric pressure dielectric barrier discharge. The main novelty of this method resides in the fact that the nanoparticles are formed in situ, inside the plasma reactor, in the gas phase. Consequently, the nanoparticle synthesis and deposition are concomitant with the solvent polymerization used to produce the matrix, which makes it possible to obtain homogeneous layers of non-agglomerated nanoparticles (NPs) with high NPs density. By toggling between low and high-frequency discharges, gold/polymer nanocomposites with different morphologies and optical properties are synthesized. The effect of the concentration of gold in the aerosol and the gas residence time in the plasma as well as the ratio of high and low-frequency discharge and their repetition rate are presented. The thin films are systematically characterized by AFM and UV–visible spectroscopy to analyze their morphologies along with their plasmonic resonances.