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

Abstract

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 ΔEg, 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.