No abstract

The sterilizing efficacy of low-pressure direct current glow discharge hydrogen peroxide (H 2 O 2) plasma generated by a planar parallel plate plasma source using the plasma enhanced chemical vapor deposition (PECVD) facility was tested. This study compares the effect of using different metals (copper, stainless steel, and aluminum) as electrodes in plasma sterilization of stainless steel dishes. Test samples were exposed to H 2 O 2 plasma under different sets of discharge currents and exposure times. Bacillus subtilis was used as the test organism and microbial analysis was made by means of the standard plate count method of serial dilution and pour plating. Evaluation of microbial death was done using survival curves, percent reduction, and decimal reduction value. Results showed that sterilization using copper electrodes exhibited the highest decimal reduction value (D-value) and percent reduction among the three electrodes. However, statistical analysis using multivariate analysis of variance (MANOVA) at 0.05 significance level assessed that the type of electrode material is not a significant factor in the H 2 O 2 plasma sterilization of Bacillus subtilis cells.

Anahaw (Livistona rotundifolia), Buri (Corypha elata) and Pandan (Pandanus amaryllifolius) leaves were plasma-treated using argon, oxygen and carbon tetrafluoride (CF4) gas under varying discharge currents (5 mA, 10 mA, 20 mA and 30 mA) for 15 minutes. The wettability properties of the plasma-treated samples were investigated using the sessile drop method to determine static contact angles on the surfaces. Based on the results, it was observed that increasing the discharge current in argon and oxygen plasma treatment was found to increase the wettability of the three samples while it decreased the wettability of Pandan and Buri samples for carbon tetrafluoride plasma.