Cold Atmospheric Pressure Plasma VUV Interactions With Surfaces: Effect of Local Gas Environment and Source Design

This study uses photoresist materials in combination with several optical filters as a diagnostic to examine the relative importance of VUV-induced surface modifications for different cold atmospheric pressure plasma (CAPP) sources. The argon fed kHz-driven ring-APPJ showed the largest ratio of VUV surface modification relative to the total modification introduced, whereas the MHz APPJ showed the largest overall surface modification. The MHz APPJ shows increased total thickness reduction and reduced VUV effect as oxygen is added to the feed gas, a condition that is often used for practical applications. We examine the influence of noble gas flow from the APPJ on the local environment. The local environment has a decisive impact on polymer modification from VUV emission as O₂ readily absorbs VUV photons.