This work directly compares vapour and liquid aerosol states for the deposition of perfluorocarbon coatings using an atmospheric pressure, non‐thermal equilibrium plasma jet system. The objective of the study is to evaluate how the physical state of the precursor (gas or liquid), influences the fragmentation of the monomer molecules in the plasma and the subsequent coating properties. Specifically the effect of gas or liquid aerosol precursor feed on the ability to achieve a soft plasma polymerization (SPP) is assessed with a view to producing a coating that exhibits minimal fragmentation, while being well cross‐linked. The precursor (perfluoro‐1‐decene) was introduced into a helium plasma and coatings deposited at rates of up to 50 nm · min−1. The deposited coatings were examined using XPS, FTIR, contact angle and ellipsometric measurements. These indicated that a controlled polymerization reaction through the vinyl group of the monomer had taken place in the case of the gas deposited samples with only minor fragmentation of the functional perfluoro chain. Furthermore, a high level of cross‐linking was achieved and the perfluorocarbon coatings were stable to a toluene wash. In contrast, while coatings deposited using the liquid deposition technique showed good retention of monomer molecular structure, they exhibited poor stability when immersed in toluene. This is attributed to lower levels of cross‐linking of the liquid precursor in the plasma, compared with coatings deposited using the gaseous precursor technique. magnified image

No abstract

Siloxane coatings were deposited using two different atmospheric plasma systems namely a reel‐to‐reel atmospheric plasma liquid deposition system called Labline™ and an atmospheric plasma jet system called PlasmaStream™. Both systems combine an atmospheric plasma, with the use of liquid precursors. The influence of the plasma source and processing conditions on the deposited coating properties were studied. The coatings were deposited onto Vycor glass and silicon wafer substrates from a liquid tetraethyl orthosilicate (TEOS) precursor which was nebulized into both He and He/O2 plasmas. Higher film growth rates were obtained using the plasma jet system; however, the reel‐to‐reel system facilitated the larger area coating of webs. The thickness (spectroscopic ellipsometry measurements) and water contact angle profile of the films deposited using the jet system on silicon wafer substrates in static mode were investigated. Amongst the other coatings characterization techniques used to evaluate the deposited coatings were optical profilometry, XPS, SEM, and AFM. The formation of particulates due to excess gas‐phase reactions during the atmospheric plasma deposition of coatings has been widely reported. In this study, larger number of particulates were observed under the conditions of higher plasma power, with the addition of O2 into the He plasma and also at low TEOS flow rates. The introduction of N2 into the He/O2 plasma, during the deposition of siloxane coatings led to a significant reduction in the number of particulates generated for both plasma sources. Nitrogen gas flow rate was varied systematically and a correlation was obtained on the influence of the flow rate of this gas on surface roughness and particulate formation.

The objective of this work was to increase color yield of direct dyes on cotton with the aid of grafted quaternary ammonium monomers. Plasma-induced graft polymerization of diallyldimethylammonium chloride (DADMAC) and [2-(acryloyloxy) ethyl] trimethylammonium chloride (AOETMAC) on cotton followed by dyeing with direct dyes was studied using different concentrations of the monomers and plasma conditions, and the color yield was evaluated using K/S measurements. Colorfastness and staining after laundering were evaluated using the standard grayscale. A significant increase of 149% in color yield was achieved when 30 g/L of DADMAC was used. 100-300% increase in K/S was achieved when ~20g/L of AOETMAC was used. To enhance the wash and lightfastness of the direct dyes on cotton, plasma-induced graft polymerization of 1,1,2,2-tetrahydroperfluorododecyl acrylate was achieved on the dyed cotton and showed considerable enhancement in both the wash and lightfastness.

No abstract