Microwave plasmas sustained at atmospheric pressure, for instance by electromagnetic surface waves, can be efficiently used to abate greenhouse-effect gases such as perfluorinated compounds. As a working example, we study the destruction and removal efficiency (DRE) of SF6 at concentrations ranging from 0.1% to 2.4% of the total gas flow where N2, utilized as a purge gas, is the carrier gas. O2 is added to the mixture at a fixed ratio of 1.2–1.5 times the concentration of SF6 to ensure full oxidation of the SF6 fragments, providing thereby scrubbable by-products. Fourier-transform infrared spectroscopy has been utilized for identification of the by-products and quantification of the residual concentration of SF6. Optical emission spectroscopy was employed to determine the gas temperature of the nitrogen plasma. In terms of operating parameters, the DRE is found to increase with increasing microwave power and decrease with increasing gas flow rate and discharge tube radius. Increasing the microwave power, in the case of a surface-wave discharge, or decreasing the gas flow rate increases the residence time of the molecules to be processed, hence, the observed DRE increase. In contrast, increasing the tube radius or the gas-flow rate increases the degree of radial contraction of the discharge and, therefore, the plasma-free space close to the tube wall: this comparatively colder region favors the reformation of the fragmented SF6 molecules, and enlarging it lowers the destruction rate. DRE values higher than 95% have been achieved at a microwave power of 6 kW with 2.4% SF6 in N2 flow rates up to 30 standard l/min.

Organic thin films were deposited by plasma-enhanced chemical vapor deposition, using isopropyl alcohol as a precursor. The pulsed, inductively coupled plasma was characterized with in situ Langmuir probe measurements and mass spectrometry. We identify the key ionized species diffusing to the substrate and offer explanations as to how they are generated. The films were analyzed with X-ray photoelectron spectroscopy. Correlations were observed between the plasma ion mass distributions and the oxidation state of the deposited carbon.

Highly exothermic polymerization reactions of monomers have been carried out in ionic liquids (ILs) by employing an accelerating‐rate calorimeter (ARC) to assess the role of the IL. The results indicate that the IL acts as an ideal heat sink in controlling the potential for the reactions to reach thermal runaway as well as contributing to a significant pressure reduction (see the acrylonitrile (AN) example depicted).

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