A novel atmospheric pressure plasma jet (APPJ) device using argon and oxygen gases was utilized to synthesize and deposit silver particles into pure cotton fabrics. The main goal of the study was to test the efficiency of the novel APPJ system for materials processing for antibacterial application. With maintained electrode distance to obey Paschen's Law, silver electrodes were placed in a glass tube powered by 15 kV. Flow rates of argon and oxygen were kept constant at 15 LPM and 5 LPM, respectively. Plasma species and electron temperature were identified using the optical emission spectroscopy results. Pure cotton fabrics were exposed to plasma for 1 min, 3 mins and 5 mins. Scanning electron microscopy and x-ray fluorescence revealed that silver particles were successfully sputtered on fabric samples. Moreover, plasma treatment also enriched the cotton samples with antibacterial property against Escherichia coli and Staphylococcus aureus as determined by modified standard disk diffusion method. These results demonstrated the surface-immobilization of plasma-synthesized silver nanoparticles on cotton fibers and the promising performance in antibacterial applications.

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A plasma sputter-type negative ion source is utilized to produce and detect negative Zr ions with energies between 150 and 450 eV via a retarding potential-type electrostatic energy analyzer. Traditional and modified semi-cylindrical Faraday cups (FC) inside the analyzer are employed to sample negative Zr ions and measure corresponding ion currents. The traditional FC registered indistinct ion current readings which are attributed to backscattering of ions and secondary electron emissions. The modified Faraday cup with biased repeller guard ring, cut out these signal distortions leaving only ringings as issues which are theoretically compensated by fitting a sigmoidal function into the data. The mean energy and energy spread are calculated using the ion current versus retarding potential data while the beam width values are determined from the data of the transverse measurement of ion current. The most energetic negative Zr ions yield tighter energy spread at 4.11 eV compared to the least energetic negative Zr ions at 4.79 eV. The smallest calculated beam width is 1.04 cm for the negative Zr ions with the highest mean energy indicating a more focused beam in contrast to the less energetic negative Zr ions due to space charge forces.

A sheet plasma device can produce a steady state high density plasma with strong density and temperature gradients. These characteristics provide efficient formation of negative hydrogen (H -) ions over a wide beam extraction area through the so called electron volume process [1]. The device configuration is suitable for plasma based materials processing. Concentrated plasma flow of the magnetized sheet plasma realizes rapid sputtering of target materials, and the produced flux of sputtered atoms can form thin functional films [2][3][4][5]. The cathode structure injects mono-energetic electron beam into sheet plasma that enables production of specific species of ions, excited neutral atoms and molecules in the produced plasma. A small sheet plasma device has been built to produce Hions, and was utilized to demonstrate the capability of controlling the surface structure of a Si substrate [3].The magnetic field structure of the sheet plasma has been improved so as to optimize the particle flux onto the sputtering target while minimizing the ion bombardment onto the produced thin film over the deposition target. Two configurations are proposed and tested. In one configuration, a simple dipole permanent magnet is attached behind the sputtering target. In the other configuration, the main plasma sheet splits into two channels. Both configurations produce enhanced sputtered particle flux and reduced ion bombardment onto the deposition target.