Soft Plasma Polymerization of Gas State Precursors from an Atmospheric Pressure Corona Plasma Discharge

Abstract

An atmospheric pressure nonthermal equilibrium corona plasma jet is described for depositing polymeric coatings with a high degree of functional chemistry retention. A long chain perfluorocarbon molecule was introduced as a vapor into a helium plasma at atmospheric pressure and coatings were deposited onto Si wafers at rates of 60-100 nm/min. XPS, FTIR and contact angle measurements indicate that a controlled polymerization reaction took place through the vinyl group of the monomer, with minimal fragmentation of the functional perfluoro chain. Electrical characterization of the corona plasma indicates that the power coupled into the jet was 6.8 W. It is proposed that low specific energy (J/cm 3 ) coupled into the plasma region is inherent to this plasma type and enables deposition of coatings with minimal fragmentation of the precursor monomer molecule. The system is inherently suitable for small-to-moderate area, high-added-value functional coating.

Electrical, Thermal and Optical Diagnostics of an Atmospheric Plasma Jet System

“…However, at 7.6 W, the discharge has expanded into the quartz tube volume, and the entire tube is heated. The average quartz tube surface temperature at 3.7 W is 319 K, while at 7.6 W the quartz tube reached a temperature of 343 K. These thermal measurements agree well with wall temperature measurements reported by Herbert et al [24].…”

“…These temperatures are higher than the quartz tube wall temperatures, as expected. Note that previous temperature measurements reported for this Plasma Chem Plasma Process plasma jet system design were not carried out in the effluent region [24]. Temperature measurements carried out in this study in the effluent region *10 mm from the nozzle resulted in a lower thermal temperature of 293 K. This indicates that the plasma activated species are rapidly cooled in the expanding effluent region to such a degree that allows heat sensitive treatment of polymeric and composite materials and many medical applications [38].…”

“…Here a dial reading 0-100 sets the power delivered to the circuit; and this is referred to as the 'set power'. Finally the surface temperature of the quartz tube was monitored using an InfraTec VarioCAM Ò high resolution infrared thermographic camera in a similar procedure as reported in reference [24].…”

“…The results of the initial electrical power characterization of the APPJ performed at a gap distance of 2.5 mm and a helium gas flow of 5 slm as a function of set power is shown in [24] for a similar APP jet system. Although there is a degree of uncertainty in the rf ground return path using this method, the measurements demonstrate the importance of measuring discharge power at the plasma rather than using the applied power measured at the input circuit.…”

Substrate Independent Dyeing of Synthetic Textiles Treated with Low-Pressure Plasmas

“…For plasma processes based on plasma-chemical reactions, however, it could be shown that both LPP and APP processes can be compared (Sawada et al, 1995). For instance, the incorporation of polar groups in ultrathin plasma polymer films might be examined yielding a permanent hydrophilic surface (Herbert et al, 2009). The deposition rate is mainly determined by the monomer flow rate due to a comparable energy input into the plasma phase.…”