This work deals with the most severe limitations of Parylene‐C coatings, namely their poor adhesion to the substrate and barrier properties. To address these limitations, the surface properties of the substrate are modified prior to the Parylene deposition step by depositing a nano‐film interfacial layer by means of a plasma polymerization process. The multilayer coating was realized using a newly designed, innovative multi‐chamber system. Tests of dry adhesion (at 90° and 180°) and electrochemical impedance spectroscopic (EIS) measurements were performed to evaluate the effect of the plasma pre‐processing. Adhesion strength of 3 and 6.8 N cm−1 were recorded for the 90° and 180° tape tests, respectively, while an impedance level of 107 Ω cm−2 at 100 Hz was registered by EIS measurement.

This work deals with the Paschen law in electrical breakdown of gases at pd values around the Paschen minimum. From the Townsend model, it is possible to deduce theoretical forms of the coefficients in Paschen's law, of which our calculated values are in the range of the tabulated values from the literature. These formulae show that the breakdown voltage must be influenced by the inter‐electrode distance, while the product pd remains a key parameter. This is confirmed by the Paschen curves measured in an argon discharge for inter‐electrode distances varying from 2 to 9 cm (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

This work deals with the luminous chemical vapour deposition (plasma polymerization) of hydrocarbon polymeric thin films in a magnetic field enhanced discharge of methane. The films were deposited on 4@ <111> single crystal silicon substrates. We investigated the influence of the different glow discharge parameters (e.g. pressure, flow rate, power input, etc.) on the deposition rate of methane and the refractive index of the resulting polymeric films, as well as the distribution of these parameters across the wafer. We used a Shinko Seiki Plasma Polymerization equipment with a bell jar reactor comprising two electrodes connected to a symmetric AC power supply of 15 kHz. Two magnetrons were formed by placing two circular shaped concentric magnetic poles behind each electrode. The substrates were attached on both sides of a rotating wheel held at a floating potential in the middle of the two electrodes. This equipment allowed us to vary a single parameter and keep the other parameters constant over the whole process. We measured the thickness and the refractive index and their distribution over the wafer. The effect of the system pressure, decoupled from the effect of flow rate, is explained by the characteristic nature of luminous gas phase and by the polymerization/deposition mechanism of luminous chemical vapour deposition.

The in vitro efficacy of transient spark disinfection was examined on different types of bacteria that are relevant in endodontics, in particular Enterococcus faecalis. A device was constructed so that it could be inserted down to the apex of prepared root canals and could be applied in conventional, regenerative, and reparative endodontics. Starting with a bacterial load of 0.2 mL of undiluted 10 9-bacteria/mL spread on a Petri dish, 3-min treatment led to a 10 6-CFU/ cm 2 reduction in bacterial load over a surface area relevant to root canal treatment.

The deposition of dielectric nanofilms by magnetron AF plasma polymerization between two planar electrodes shows a number of advantages over the standard RF method without magnetron enhancement. Because it is powered at 15 kHz, it works as a DC discharge swapping side every half cycle. We investigated here the effect of the magnetron on the breakdown voltage in our system taking Paschen curves with a DC power source. Subsequently, we related the Paschen curves with the deposition rate of the coating, showing that the Paschen minimum corresponds to the maximum growth rate as far as the pressure and the inter‐electrode distance are concerned. This result can be used to quickly determine the maximum growth rate in a given configuration via the measurement of a Paschen curve (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)