Effect of Plasma Exposure on the Chemistry and Morphology of Aerosol‐Assisted, Plasma‐Deposited Coatings

Abstract

This study reports on the effect on the morphology and chemistry of atmospheric pressure plasma deposited nm‐thick coatings (21 ± 3 nm) as the level of exposure to the plasma is systematically altered. Coatings were deposited by directly injecting hexamethyldisiloxane, polydimethylsiloxane or tetramethyldisiloxane liquid precursors through a nebulizer into a helium/oxygen atmospheric pressure plasma. An increase in the level of the precursor was found to be associated with a decrease in the concentration of methyl functional groups in the coating and to an increase of the SiO crosslinking, as demonstrated using surface energy and XPS analysis. This resulted in an increase in the coating refractive index, and in a reduction of the number of surface particulates, as well as of surface roughness.magnified image

Atmospheric pressure plasma treatment of amorphous polyethylene terephthalate for enhanced heatsealing properties

“…This is related to the motion and reorientation of hydrophilic functionalities away from the surface and towards the bulk of the polymer. This is commonly referred to as hydrophobic recovery [26,27]. Chemical functionality of the plasma treated APET material In order to determine the effect of the plasma treatment on the polymer a surface analysis study was carried out.…”

Correlation Between the Electrical and Optical Properties of an Atmospheric Pressure Plasma During Siloxane Coating Deposition

“…With increasing power the number of discharge events, per half cycle of the waveform, increased from 1 to 13 at 2,000 W for both He and He/O 2 discharges. Such multiple discharges per half cycle, varying in number with both the frequency and amplitude of the applied voltage, have been previously reported in DBDs [18,[29][30][31]. These are generally explained as resulting from the maximum applied voltage exceeding the threshold breakdown voltage for the gap.…”

“…The coatings were deposited using the Dow Corning Ò SE-1100 Labline TM atmospheric pressure plasma system [18]. It comprises 2 vertical parallel-plate plasma chambers arranged in conjunction with a dedicated polymer film handling system.…”

“…It has been demonstrated previously that surface energy measurements provide an indication of surface chemistry (level of oxidation) and precursor plasma polymerization [18,23]. The surface energy was determined according to the sessile drop technique using an OCA 20 video capture apparatus from Dataphysics Instruments.…”

“…The introduction of a liquid precursor is typically carried out in the form of an aerosol via direct injection [14,15] or as a gas via a bubbler system [16,17]. Extensive analysis of coatings deposited in DBD systems has also enabled a detailed understanding of the precursor polymerisation, dissociation and deposition [18][19][20][21].…”