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Cold Plasma (cold + plasma)

Distribution by Scientific Domains

Polymers and Materials Science	80%

Selected Abstracts

Atmospheric Cold Plasmas for Synthesizing Nanocrystalline Anatase TiO2 using Dielectric Barrier Discharges

PLASMA PROCESSES AND POLYMERS, Issue 5 2007
Long-Hui Nie
Abstract Nanocrystalline anatase TiO2 has been successfully synthesized using TiCl4 and O2 as precursors by atmospheric cold plasmas generated by dielectric barrier discharges (DBD) without extra heating or thermal treatment. For the TiO2 powders synthesized by DBD plasma at an energy density of 5.9 kJ,·,L,1, XRD and TEM analyses revealed that the nanocrystallite size is about 10,15 nm. Only a single crystalline structure of anatase was observed performing XRD, HRTEM and SAED measurements. It was found that the particle size decreased with increasing the discharge power, and that the chlorine contamination dramatically decreased when using high discharge power levels. [source]

Mechanical behavior of cold plasma,treated sisal and high-density polyethylene composites

POLYMER COMPOSITES, Issue 3 2003
Adriana R. Martin
Sisal fibers and finely powdered high-density polyethylene were surface functionalized with dichlorosilane on a RF(radio frequency)-plasma reactor. Composites made from sisal and high-density polyethylene were compounded using a thermokinetic mixer. The discharged mass was cooled, granulated, and injected molded into composite specimens for testing. The mechanical behaviors (tensile, impact and thermal dynamical mechanical properties) of composites made from cold plasma-treated and untreated components are compared and discussed. The best mechanical performance was generally obtained for composites where only the inert thermoplastic matrix was plasma-functionalized. Plasma treatment of lignocellulosic fibers seems to induce decomposition processes of the surface layers structures exposed to the plasma that generally does not contribute to significant improvement on the mechanical behavior of the composite. [source]

Impact of Low-Temperature Plasmas on Deinococcusradiodurans and Biomolecules

BIOTECHNOLOGY PROGRESS, Issue 3 2003
Rakesh Mogul
The effects of cold plasma on Deinococcus radiodurans, plasmid DNA, and model proteins were assessed using microbiological, spectrometric, and biochemical techniques. In low power O2 plasma (,25 W, ,45 mTorr, 90 min), D. radiodurans, a radiation-resistant bacterium, showed a 99.999% reduction in bioburden. In higher power O2 plasma (100 W and 500 mTorr), the reduction rate increased about 10-fold and observation by atomic force microscopy showed significant damage to the cell. Damage to cellular lipids, proteins, and chromosome was indicated by losses of infrared spectroscopic peaks at 2930, 1651, 1538, and 1245 cm - 1, respectively. In vitro experiments show that O2 plasmas induce DNA strand scissions and cross-linking as well as reduction of enzyme activity. The observed degradation and removal of biomolecules was power-dependent. Exposures to 200 W at 500 mTorr removed biomolecules to below detection limits in 60 s. Emission spectroscopy indicated that D. radiodurans cells were volatilized into CO2, CO, N2, and H2O, confirming that these plasmas were removing complex biological matter from surfaces. A CO2 plasma was not as effective as the O2 plasma, indicating the importance of plasma composition and the dominant role of chemical degradation. Together, these findings have implications for NASA planetary protection schemes and for the contamination of Mars. [source]

Improvement of the Optical Transmission of Polymer Planar Waveguides by Plasma Treatment

PLASMA PROCESSES AND POLYMERS, Issue 3 2008
Aissam Airoudj
Abstract The aim of the present work is to reduce the optical losses of glycidyl ether of bisphenol A (SU-8) polymer planar waveguides using cold plasmas, which allow the substitution of H atoms by F. CF4 and mixtures of CF4/H2 RF plasma treatments were carried out for the surface fluorination of the SU-8 waveguide. The observed decrease in the optical losses due to propagation in the Si/SiO2/fluorinated SU-8 planar waveguides has been correlated with the surface fluorination as measured by XPS and CA measurements. In order to understand and to optimize the fluorination process, the plasma phase was analyzed by OES. Finally, the thickness of the fluorinated layer was estimated using modulated incident-angle XPS. [source]