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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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

A large research reactor for dielectric barrier discharge (DBD) experiments at atmospheric pressure (AP) has been used with argon (Ar) carrier gas under constant plasma conditions ( f = 20 kHz, Va( f) = 8 kVp-p = 2.8 kVrms). Five esters, acrylates with differing number of unsaturations were used as 'monomers'; monomer flows, Fd, were at ‰ concentrations in the F = 10 standard liters per minute (slm) of argon. We earlier perfected and reported a method for measuring Eg, the energy dissipated per cycle of the applied a.c. voltage, and Δ Eg, the energy difference with and without monomer in the Ar flow. The latter, combined with Fd enable calculation of Em, the average energy absorbed from the plasma per monomer molecule. Plots of Em versus Fd and 1/ Fd yield much valuable information, for example about the role of CC and CC bonds in fragmentation and polymerization reactions. Fourier-transform infrared (FTIR) spectroscopy, spectroscopic ellipsometry (SE), and scanning electron microscopy (FEG-SEM) further enhance and complement data interpretation. [ABSTRACT FROM AUTHOR]

In the plasma polymerization literature, there has been an interest since at least the 1970s to correlate the structure of plasma polymer (PP) deposits with plasma parameters during deposition, most particularly with the energy input per monomer molecule, Em. In our two laboratories, we have developed methods for measuring Em (or somewhat equivalent, Ea) in low- (LP) and atmospheric-pressure (AP) discharge plasmas. In this article we propose a new parameter, the so-called energy conversion efficiency, ECE, which permits direct comparison of LP and AP experiments. This is done for the case of three model monomer compounds, ethane, acetylene, and acrylic acid (AAc). 'Critical' energy values that demarcate ECE regimes separating different fragmentation/reaction mechanisms agree remarkably well for all three monomers examined; resulting Em (or Ea) values are correlated with specific mechanisms, and the numerical results are convincingly supported by data from the chemical literature. [ABSTRACT FROM AUTHOR]

The method developed for fundamental understanding of energetic exchanges between monomer molecules and argon carrier gas in a dielectric barrier discharge (DBD) has previously proven merit. In this seventh article related to this methodology, research has been extended to a new family of precursors: anhydrides. Monomers (typically ‰) were mixed with 10 slm of Ar in a 20 kHz, 8 kV (peak‐to‐peak) DBD corresponding to an energy per cycle of 1600 μJ for pure Ar. For each of the investigated monomers Em, the energy absorbed per molecule was plotted as a function of precursor flow rate. The influence of chemical structure (C/O ratio, unsaturation) has been investigated and compared with previous data for other types of precursors. Thin plasma polymer coatings were deposited; in addition to measuring deposition rates, we also present relationships between Em values, spectro‐ellipsometric and FTIR measurements. [ABSTRACT FROM AUTHOR]