Abstract
A catalytic sensor for the measurement of radical density in weakly ionized CO2 plasmas, created in a low-pressure electrodeless discharge, is presented. The CO2 plasma was created in a 4 cm wide borosilicate glass tube inside a copper coil connected to a radio frequency generator operating at 27.12 MHz with a nominal power of 250 W. The dissociation fraction of the CO2 molecules was measured in the early afterglow at pressures ranging from 10 Pa to 100 Pa, and at distances of up to 35 cm along the gas stream from the glowing plasma. The radical density peaked (2 × 1020 m−3) at 80 Pa. The density quickly decreased with increasing distance from the glowing plasma despite a rather large drift velocity. The dissociation fraction showed similar behavior, except that the maximum was obtained at somewhat lower pressure. The results were explained by rather intense surface recombination of radicals.
Highlights
Oxidative plasmas are a popular medium for modification of the surface properties of solid materials
Reactive particles created in the oxidative plasma react with solid materials at much lower temperature than the parent molecules, and this allows for surface modification of the materials at relatively low temperature
The role of plasma irradiation on the probe was measured with an optical emission spectrometer (OES) with sensitivity of 14,000 counts μW–1 per ms integration time
Summary
Oxidative plasmas are a popular medium for modification of the surface properties of solid materials. Reactive particles created in the oxidative plasma react with solid materials at much lower temperature than the parent molecules, and this allows for surface modification of the materials at relatively low temperature. This treatment often leads to unique surface properties for the treated materials. Powerful discharges are suitable for production of large quantities of metal oxide nanoparticles [7,10] They are too aggressive for treatment of polymer materials, let alone delicate biomedical samples [11]. A small problem arising from application of plasmas created in discharges at low power is the ignition phenomenon. With some modifications of the heterogeneous recombination model on a probe, radical densities in an early afterglow of a plasma created in a CO2 electrodeless radiofrequency discharge can be determined
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
