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Looking at the increasing scope of plasma processing of materials surface, here we present the development and diagnostics of a microwave assisted Electron Cyclotron Resonance (ECR) plasma system suitable for surface modification of polymers. Prior to the surface-treatment, a detailed diagnostic mapping of the plasma parameters throughout the reactor chamber was carried out by using single and double Langmuir probe measurements in Ar plasma. Conventional analysis of I-V curves as well as the elucidation form of the Electron Energy Distribution Function (EEDF) has become the source of calibration of plasma parameters in the reaction chamber. The high energy tail in the EEDF of electron temperature is seen to extend beyond 60 eV, at much larger distances from the ECR zone. This proves the suitability of the rector for plasma processing, since the electron energy is much beyond the threshold energy of bond breaking in most of the polymers. Nylon 6 is used as a representative candidate for surface processing in the presence of Ar, H + N, and O plasma, treated at different locations inside the plasma chamber. In a typical case, the work of adhesion is seen to almost get doubled when treated with oxygen plasma. Morphology of the plasma treated surface and its hydrophilicity are discussed in view of the variation in electron density and electron temperature at these locations. Nano-protrusions arising from plasma treatment are set to be responsible for the hydrophobicity. Chemical sputtering and physical sputtering are seen to influence the surface morphology on account of sufficient electron energies and increased plasma potential.

Gas discharge plasma is being explored nowadays for its application as an alternative to the conventional sterilization and disinfection techniques in medical sciences. We have developed the non-thermal atmospheric plasma torch to study the effect of plasma treatment on the growth rate of E. faecalis culture and biofilms. E. faecalis treated with plasma was then compared with helium gas exposed and chlorohexidine treated cultures and biofilms. All the results are analysed for significance (P < 0.001) using ANOVA and TUCKEY'S test. Optical emission spectroscopy technique has been employed in. situ to identify the species interacting with the samples. It is found that atmospheric non-thermal plasma proves to be a promising alternative to traditional disinfectants for disinfection during endodontic treatment.

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The paper presents an improved method of depositing nanocrystalline thin films of Fe-doped TiO 2 to be used as a reusable cyclic photocatalyst for degrading the organic pollutants. The technique of electron cyclotron resonance plasma-enhanced chemical vapor deposition was employed with titanium tetra-isopropoxide (C 12 H 28 O 4 Ti) and ferrocene (C 10 H 10 Fe) as precursors of Ti and Fe, respectively. Optical emission spectroscopy was used to identify the reactive species, to determine the electron temperature and the ion density during deposition. The films were characterized using optical absorption and photoluminescence spectra, whereas the morphological analysis was carried out with scanning electron microscopy. Strong adhesion of the deposited films with the substrate ruled out any possibility of TiO 2 particles being leached out. It was confirmed by observing the degradation rate of the same film repeatedly. Cyclic use of the film for the catalytic reactions thus makes the process much user friendly for the water treatment.