Energetics of reactions in a dielectric barrier discharge with argon carrier gas: V hydrocarbons

Abstract

We report dielectric barrier discharge (DBD)‐based atmospheric pressure (AP) plasma polymerization (PP) experiments using argon carrier gas and a wide variety of hydrocarbon molecules as the precursors (“monomers”). As in our preceding research with other reagents, unprecedented precision and reproducibility in energy measurements is again demonstrated. Measurements based on various aliphatic and aromatic hydrocarbon compounds have yielded values of Em, the energy absorbed from the plasma by each monomer molecule. Systematic differences among families of compounds enabled us to draw several important conclusions about fragmentation and polymerization in the DBD plasma environment, observations which are in fair qualitative agreement with low‐pressure radio‐frequency PP data by Yasuda and Hirotsu from the 1970s.

Energetics of reactions in a dielectric barrier discharge with argon carrier gas: VI PEG‐like coatings

“…Here, values for 1G and 2G were 61 eV and 76.1 eV, respectively. In agreement with previous work, the heavier molecule exhibits a significantly higher value of ; a “monomer‐rich” region spreading over high values, where smoothly decreases with rising . Figure b also shows plots of , this time versus 1/, and it reveals quasi ‐linear behavior in the monomer‐rich region, something that we had already amply discussed in our earlier reports .…”

“…Here, E m ð Þ max values for 1G and 2G were 61 eV and 76.1 eV, respectively. In agreement with previous work, [32] the heavier molecule exhibits a significantly higher value of E m ð Þ max ; (ii) a "monomer-rich" region spreading over high F d values,…”

“…The parameters Ψ and Δ were determined at 45°, 55°, 65°, and 75° incidence angles using a J. A. Woollam RC2® instrument operating in the 193‐1700 nm wavelength range, and they were interpreted using CompleteEASE™ software with a Gaussian oscillator ‐ based optical model Attenuated total reflectance (ATR) Fourier‐transform infrared (FTIR) spectroscopy measurements were performed using a Digilab® FTS 7000 spectrometer, equipped with a UMA 600 microscope and a hemispherical Ge ATR crystal, for operation in the region from 4000 to 700 cm −1 .…”

“…Some of the present authors have recently shown that dielectric barrier discharge (DBD) plasmas with Ar as carrier gas can be used to deposit PP coatings from a wide variety of monomers, with precise knowledge of the energy per precursor molecule, , absorbed from the plasma's “energy reservoir.” In recent joint communications with D. Hegemann, this approach was even shown to permit comparisons between AP and LP PP processes, based on a new “energy conversion efficiency” (ECE) parameter reminiscent of the “Yasuda parameter— W/FM ” concept from the 1970s and 80s …”

“…Some of the present authors have recently shown that dielectric barrier discharge (DBD) plasmas with Ar as carrier gas can be used to deposit PP coatings from a wide variety of monomers, with precise knowledge of the energy per precursor molecule, E m , absorbed from the plasma's "energy reservoir." [29][30][31][32] In recent joint communications with D. Hegemann, [33,34] this approach was even shown to permit comparisons between AP and LP PP processes, based on a new "energy conversion efficiency" (ECE) parameter reminiscent of the "Yasuda parameter-W/FM" concept from the 1970s and 80s. [35] In this present research, we adopted our above-cited AP DBD methodology as a routine tool for depositing PP-PEG using low molecular weight monoglyme (1G) and diglyme (2G) as precursors (see Figure 1), and we henceforth refer to the resulting coatings as PP-1G and PP-2G, respectively.…”