Study of the Effect of Low-Temperature Plasma Exposure on Mould Fungi Colonizing Paper

The influence of radiofrequency cold plasma in ambient air at 200 Pa pressure on mould fungi of the genus Aspergillus was studied. It was shown that 20 min plasma treatment of paper with mould and contamination reduced the number of colony forming units but didn't lead to complete suppression of fungal viability. Strains of A. versicolor after plasma treatment lost the ability to excrete pink pigment to the environment. A. niger strains were more resistant and kept acidification ability. One of the possible plasma inactivation factors was formation of reactive hydroxyl (OH) radical

ATMOSPHERIC PRESSURE H 2 O PLASMA TREATMENT OF POLYESTER CORD THREADS

Polyester cord threads, which are used as a reinforcing materials of rubber blend, have been treated in atmospheric-pressure H2O plasma in order to enhance their adhesion to rubber. The atmospheric-pressure H2O plasma was generated in an underwater diaphragm discharge. The plasma treatment resulted in approximately 100% improvement in the adhesion. Scanning electron microscopy investigation indicates that not only introduced surface polar groups but also increased surface area of the fibres due to a fibre surface roughening are responsible for the improved adhesive strength

Underwater pulse electrical diaphragm discharges for surface treatment of fibrous polymeric materials

Preliminary results on physical characteristics of pulsed underwater diaphragm electrical discharges are presented. The discharges burning in tap water, water-chelaton solutions, and some other water-based solutions were studied as a potential atmospheric-pressure H2O-plasma source for surface activation of polyester cord threads. The discharge plasma parameters have been measured by means of optical emission spectroscopy. Electron number density of roughly 2 x 10(8) cm(-3) and an electron temperature of 1x10(4) K were estimated from broadening of hydrogen lines (Halpha), and vibrational temperature of 2500 K was determined from the vibrational band of nitrogen. A significant increase in the surface energy and wettability of the cord threads due to the plasma treatment was obtained.</p

Comparative study of diffuse barrier discharges in neon and helium

Abstract Diffuse dielectric barrier discharges in neon and helium at atmospheric pressure were studied. The discharges were generated between two metal electrodes, both covered by an alumina layer and driven by ac voltage of frequency 10 kHz. The discharge gap was 2.2 mm and 5 mm, respectively. The discharges were investigated by electrical measurements and by temporally and spatially resolved optical emission spectroscopy. The experimental results revealed similar discharge behaviour in both gases being considered. Although the discharges were ignited at slightly different electric field strengths, their evolutions were found to be similar. At maximum discharge current the spatial light intensity distribution was characterized by the formation of a cathode fall. A difference was observed in the magnitudes of the current density only. In addition to the regime with a single discharge pulse per voltage half period T /2, a discharge mode with two and more subsequent current pulses per T /2 (also referred to as the pseudoglow discharge regime in the literature) was obtained due to an increase in the voltage amplitude or an admixture of nitrogen

Generation of Supersonic Plasma Flow by Means of Unipolar RF Discharges

Recently the unipolar discharges has been used as a plasma source which employ the flow of the working gas for the creation of plasma channels : At first the radio frequency unipolar one hollow cathode discharge the cathode of which acts simultaneously as a nozzle for working gas inlet to the reactor chamber has been used in the particular applications.[1,2]. On the base of this reactor the plasma-chemical reactor with a system of unipolar multi-hollow-cathode discharges has been developed. This reactor is able to deposit the composite thin films and multi-layer structures onto internal walls of cavities, tubes and on the components with complicated shapes. Secondly the RF unipolar torch discharge has been used as a source of the plasma Channel. The advantage of this system is that it is possible to use it up to atmospheric pressure of the working gas and even in the liquid environment[3],[4]. In the present report the generation of the plasma channels by means of mentioned RF unipolar plasma discharges is discussed. At first the devices with RF unipolar hollow cathode discharge are presented and after that the device with the torch discharge is mentioned