In this research, a diffuse coplanar surface barrier discharge (DCSBD) type plasma reactor was used for the surface modification of raw linen fabric. Changes in physical properties and chemical composition of the fiber surface as well as color of the fabric were measured as a function of time of the atmospheric air plasma treatment. Furthermore, ageing of the effects created on the fiber surface by plasma treatment was also characterized in a period of 0-14 days elapsed after the plasma treatment. Significant differences were found between the properties of the raw and plasma treated linen fabrics, including increase of wettability, wickability, surface energy and O/C ratio, and decrease of water contact angle and deterioration of the waxy outer layer of the fibers. Most of the parameters depended on the time of plasma treatment (0–180 s). O/C ratio increased steadily with the increase of duration of the plasma treatment, which was explained by destruction of the waxy surface layer, creation of polar groups and exposure of cellulosic components. Most of the properties tested were found to be stable during two weeks of storage after the plasma treatment, indicating that the surface ‘topography’ created by plasma remained almost unaltered and the recovery of the etched waxy coverage of the fiber did not occur.
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An air diffuse coplanar surface barrier discharge is used to activate the surface of polytetrafluoroethylene (PTFE) samples, which are subsequently coated with polyvinylpyrrolidone (PVP) and tannic acid (TAN) single, bi- and multilayers, respectively, using the dip-coating method. The surfaces are characterized by X-ray Photoelectron Spectroscopy (XPS), Attenuated Total Reflection – Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Atomic Force Microscopy (AFM). The XPS measurements show that with plasma treatment the F/C atomic ratio in the PTFE surface decreases, due to the diminution of the concentration of CF2 moieties, and also oxygen incorporation through formation of new C–O, C=O and O=C–O bonds can be observed. In the case of coated samples, the new bonds indicated by XPS show the bonding between the organic layer and the surface, and thus the stability of layers, while the gradual decrease of the concentration of F atoms with the number of deposited layers proves the creation of PVP/TAN bi- and multi-layers. According to the ATR-FTIR spectra, in the case of PVP/TAN multilayer hydrogen bonding develops between the PVP and TAN, which assures the stability of the multilayer. The AFM lateral friction measurements show that the macromolecular layers homogeneously coat the plasma treated PTFE surface.
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Atmospheric-pressure air and nitrogen plasmas generated by surface dielectric barrier discharges have been used to incorporate new functionalities at the surface of polypropylene nonwoven fabric. The main goals were to activate the polymer surfaces for subsequent immobilization of chitosan from water solution without using any crosslinking and wetting agents. The samples were analyzed by diffuse reflectance infrared Fourier transform spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. The nitrogen plasma treatment resulted in relatively high oxygen incorporation, about 9 atomic % mainly in aliphatic C=O type bonds and about 4 at.% of nitrogen incorporation in amine and other nitrogen functionalities. Chitosan was immobilized on the fabric fibers surfaces very homogeneously in amount of 2 - 5 g m-2. The chitosan coated samples exhibited a good laundering durability and strong antimicrobial activity against Bacillus subtilis and Escherichia coli.
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