Fourier‐transform infrared spectroscopy of ethyl lactate decomposition and thin‐film coating in a filamentary and a glow dielectric barrier discharge

• Published in: Plasma processes and polymers Vol. 18; no. 7
• Main Authors: Milaniak, Natalia, Laroche, Gaétan, Massines, Françoise
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01-07-2021; Wiley-VCH Verlag
• Subjects: biomaterials; Chemical bonds; chemical composition; Chemical Sciences; Chemical vapor deposition; Decomposition; Dielectric barrier discharge; Dielectrics; Ethyl lactate; FSK; FTIR; Gas flow; in situ spectroscopy; Infrared spectroscopy; Material chemistry; plasma; Spectrum analysis; thin film; in-situ spectroscopy; FTIR; thin film; dielectric barrier discharge; biomaterials; plasma; chemical composition; FSK
• ISSN: 1612-8850; 1612-8869
• DOI: 10.1002/ppap.202000248

Glow 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.
Atmospheric pressure plasma enhanced chemical vapor deposition (AP PECVD) in a dielectric barrier discharge (DBD) configuration was used for thin film synthesis. Ethyl lactate (EL) decomposition in glow and filamentary discharges was followed using a space‐resolved in‐situ FTIR system. Calibration curves were built to measure the concentration of EL molecular bonds and plot their concentration evolution as a function of the energy provided per precursor molecule. These data were correlated with the composition of the deposited coatings, as deduced from their FTIR spectra, recorded at corresponding positions.