Energetics of Reactions in a Dielectric Barrier Discharge with Argon Carrier Gas: III Esters

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, V-a(f) = 8kV(p-p) = 2.8 kV(rms)). Five esters, acrylates with differing number of unsaturations were used as monomers; monomer flows, F-d, were at% concentrations in the F = 10 standard liters per minute (slm) of argon. We earlier perfected and reported a method for measuring E-g, the energy dissipated per cycle of the applied a.c. voltage, and Delta E-g, the energy difference with and without monomer in the Ar flow. The latter, combined with F-d enable calculation of E-m, the average energy absorbed from the plasma per monomer molecule. Plots of E-m versus F-d and 1/F-d 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.