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Polypropylene and nylon 66 fabrics are subjected to atmospheric pressure He and He-O 2 plasmas for selected exposure time intervals. Scanning electron microscopy analysis of the fabrics shows no apparent changes in the plasma-treated nylon fiber surfaces, but significant surface morphological changes for the polypropylene. Surface analyses of the nylon filaments reveal small differences in the surface carbon and oxygen contents between the treated and control groups. The surface oxygen and nitrogen content of the polypropylene fabric increases significantly after treatment in both He and He-O 2 plasmas. There is a slight decrease in nylon fabric tensile strength after treatment in He plasma for 3 minutes, while. there is no significant change in tensile strength of the nylon fabric treated with He-O 2 after exposure times of up to 8 minutes.Plasma treatment of textile fabrics and yams is being investigated as an alternative to wet-chemical fabric treatment and pretreatment processes, e.g., shrink resistant (wool) or water-repellent finishing, which tend to alter fabric mechanical properties and are environmentally hazardous. Plasma treatment of textiles may result in desirable surface modifications, including but not limited to surface etching, surface activation. crosslinking, chain scission, decrystallization, and oxidation. Treatment depends on the choice of working gas and plasma density and energy [ 1,3,6,14,17,19]. The effects of low-pressure (vacuum) plasma treatments of polyester, high performance polymers, and wool are well documented [3, 11, 17, 191, while relatively little has been published about atmospheric pressure plasma treatments [4, 14, 171. Despite the effectiveness of plasma treatments on textiles, the inability to successfully incorporate low-pressure plasma treatment equipment into a continuous textile finishing operation has seriously limited the commercial viability of the technique [ 11 ]. Previously, plasmas generated at atmospheric pressure were believed to be neither uniform nor stable: however, recent research on atmospheric plasmas has shown their uniformity, stability, and applicability to processing and treatment of textiles, as well as many other materials [2]. In addition, atmospheric pressure plasma treatment devices can be integrated with continuous on-line processing of textile materials.While plasma treatment may result in many favorable or desirable surface modifications of textile materials. it may also cause undesirable physical degradation of the polymer surface [5,10,11 ]. Treatment parameters must be optimized in order to achieve desirable surface modifications without changing bulk properties. This paper presents results on polypropylene and nylon 66 fabrics treated with atmospheric plasmas of helium (He) and a mixture of helium and oxygen (He-02). Helium is typically used to initiate and generate the plasma at atmospheric pressure before another gas is introduced to the system. If there are no measurable changes in surface or mechanical properties as a result of e...

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Cotton fabrics were treated by radio-frequency plasma with tetrafluoromethane (CF 4 ) and hexafluoropropene (C 3 F 6 ) gases under different exposure times, pressures, and power levels. The hydrophobicity and water repellency were analyzed with measurements of the cosine of the contact angle (cos ) and wet-out time. The hydrophobicity was enhanced with treatments of both gases. Xray photoelectron spectroscopy (XPS) revealed increases in the surface fluorine content of 1-2% for CF 4 plasma and of 2.3-7.8% for C 3 F 6 plasma. The relative chemical composition of the C 1s spectra after CF 4 and C 3 F 6 plasma treatments showed increases in the relative amounts of OCOOOCO and fluorocarbon groups (OCF, OCF 2 , and OCF 3 ), whereas peak areas for OCOH and OCOOH decreased. The hydrophobicity was enhanced by the increase in the fluorine content and fluorocarbon groups. C 3 F 6 plasma treatment resulted in higher hydrophobicity than CF 4 plasma treatment according to not only cos and wet-out measurements but also XPS analysis.

Plasma treatments are gaining popularity in the textile industry due to their numerous advantages over conventional wet processing techniques. In this study, the nonwoven fabric Sontara®, commonly used for surgical gowns, is treated with antimicrobial finishes and a plasma containing fluorocarbon gas. Treated samples are evaluated for changes in physical and functional characteristics. The plasma treatment does not alter the weight, thickness, stiffness, air permeability, and breaking strength and elongation. Plasma-treated and water-repellent Sontara samples show higher blood and water resistance compared to other treatments. Plasma-treated samples also show a zone of inhibition for Staphylococcus aureus, thus providing a barrier against microbes. There is no zone of inhibition for the water repellent Sontara, untreated, and wet control samples. This implies that the nonwoven fabric treated with plasma can provide a better barrier against microbes than commonly available surgical gown fabric with a fluorocarbon finish.

The effect of plasma treatment on surface characteristics of polyethylene terephthalate films was investigated using helium and oxygenated-helium atmospheric plasmas. Sample exposure to plasma was conducted in a closed ventilation test cell inside the main plasma chamber with variable exposure times. The percent weigh loss of the samples showed an initial increase followed by decrease with extended exposure time, indicating a combined mechanism of etching and redeposition. The wettability as measured by the contact angle showed a sharp initial increase followed by a steady-state trend with increased exposure time, suggesting a change in surface functionality. Atomic force microscopy analysis revealed increase in surface roughness, as well as evidence of redeposition of etched volatiles. Functionality changes were measured using X-ray photoelectron spectroscopy and these changes were correlated to the new plasma-induced properties.

The electrospinnability of polyethylene oxide (PEO) was manipulated by atmospheric plasma treatment of pre-electrospinning solutions. Conductivity, viscosity, and surface tension of PEO solutions increased after plasma treatment, and the plasma effect remained longer when the solution concentrate increased. Both untreated and treated solutions were then electrospun, and the morphology of the resultant nanofibers was observed by SEM. Atmospheric plasma treatment improved the electrospinnability of PEO solutions and led to less beads and finer diameter distribution in the resultant nanofibers. Additionally, plasma treatment of the pre-electrospinning solutions affected the crystal structure of resultant nanofibers. These results suggest that atmospheric plasma treatment is a feasible approach to improve the electrospinnability of polymer solutions and can used to control the structure of electrospun nanofibers.