Design and evaluation of plasma polymer deposition on hollow objects by electrical plasma generated from the liquid surface

Abstract

Recently, plasma deposition at atmospheric pressure has become a promising technology due to its reduced equipment costs and its possibility of in‐line processing. The main aim of this work was to show a process for the deposition of functional layers on hollow objects surface by plasma discharge generated above the liquid electrolyte. In principle, this process is based on the surface dielectric barrier discharge, where the plasma is generated from the boundary line of liquid precursor and dielectric surface. As a model precursor compound a hexamethyldisiloxane was chosen for deposition on external and internal wall surface of polytetrafluoroethylene tube.

Electrical analysis and ultra-fast sequential imaging of surface barrier discharge with streamer-leader sequence generated with 100 kHz frequency at the water interface

“…even 2 μs after the current peak the discharge generates an active plasma (look at the left branch). This is similar to what has been observed for coplanar barrier discharge in air [29] and is of beneficial importance for application of such types of surface discharges [3][4][5]. Moreover, the decay of the branches and their re-ignition (re-ionisation and re-excitation processes in the electrified gas) was evidenced here in its characteristic time-scale and partly supports the hypothesis proposed in our previous work for high-power surface discharges [8], that plasma filaments generated surface leaders can serve as a stabilised path for discharge reignition in subsequent periods.…”

“…Recently, water-containing plasmas have attracted intensive attention again, mostly due to the emerging applications in plasma medicine [1], or constant interests in water decontamination [2] or polymer surface treatment [3,4]. A special case of the discharge generation in contact with water is the surface barrier discharge, where one electrode is created by water [5].…”

“…As a consequence, transient plasma is generated at this interface. This phenomenon is considered a complication in electrowetting devices [6], or it can be favourable for polymer surface treatment [3] or deposition [4].…”

“…The investigated discharge system, the surface barrier discharge (surface BD or SBD) generated from the water interface (as it is used in various arrangements also for applications [3][4][5]), is schematically shown in figure 1. Although relatively simple, the presence of the wetting water interface and dielectric surface poses the following challenges related to microscopical complexity of the system: detailed estimation of the instantaneous charge transfer to the liquid at the triple-line, and instantaneous development of the light emission related to the charge transfer with reasonable resolution.…”

Deposition of SiOxCyHz Protective Coatings on Polymer Substrates in an Industrial-Scale PECVD Reactor

“…Some attempts have also been made to coat materials immersed into liquid HMDSO and apply atmospheric-pressure plasma next to the liquid surface. The most recent paper was published by Pavlinak et al [14], who created plasma above liquid HMDSO and successfully coated Teflon tubes with a thin film resembling polydimethylsiloxane. Obviously, such treatments cannot be used for the deposition of SiO x coatings.…”