Energetics of reactions in a dielectric barrier discharge with argon carrier gas: IV ethyl lactate

Abstract

We report dielectric barrier discharge (DBD)‐based atmospheric pressure (AP) plasma enhanced chemical vapor deposition (PECVD) experiments using argon carrier gas and ethyl lactate (EL) as the precursor molecule (“monomer”). As in our preceding research with other monomers, unprecedented precision and reproducibility is again demonstrated, here to create plasma polymerized (PP‐EL) deposits. PP‐EL is thought to be an excellent candidate for bio‐medical applications on account of the non‐toxic nature of resulting PP‐EL deposits. We have shown that a narrow range of energy values absorbed from the plasma, Em, between roughly 21 and 42 eV/molecule, lead to PP‐EL coatings of widely varying structural and physical properties, ones with controlled retention of chemical features of the EL monomer, and a predictable rate of degradation in aqueous media.

Energy of reactions in atmospheric‐pressure plasma polymerization with inert carrier gas

“…To be further reassured, we have verified the energy calculations for all of our E m values (refs. ) and have found systematic error to be <0.1% in all cases. For instance, in the CH 4 /Ar mixture shown in Figure , the value of E g changes from 1191.8 to 1191.5 μJ after correction, a difference of only 0.025%.…”

“…Over the past several years, this laboratory has undertaken and published several studies related to the topic described in the title above . In the first article, we presented methodology for determining E g , the energy dissipated per cycle of the applied a.c. high voltage, V a ( f ); this then enabled us to measure E m , the energy absorbed per molecule of volatile organic (“monomer”) additive in the 10 slm flow of noble carrier gas (namely argon, Ar) .…”

“…Of course, the main concern at this point was to determine whether or not the correction had a possible impact upon values of E g and E m in articles that were published at later dates, and in which the content hinged to a very large extent on the precision of energy determinations.…”

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

“…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 .…”

“…Earlier experience [37] taught us that the upper limit of region (iii) (lower limit of [ii], see Figure 2) corresponds to the one of interest for most PP experiments. For both precursors a few such conditions were therefore selected, with E m values ranging upward from ca.…”