Silicon oxide based (SiOxCyHz, noted SiOx) coatings are often used in surface engineering for microelectronics, corrosion resistance, barrier to gas permeation through polymeric materials, etc… SiOx coatings can be efficiently deposited by non‐equilibrium atmospheric pressure plasma processes, such as DBD or plasma jets. In the present study, the design of experiment (DoE) methodology was used to investigate the influence of process parameters on the characteristics of organosilicon coatings deposited by a non‐equilibrium atmospheric pressure plasma jet (APPJ) from hexamethyldisiloxane (HMDSO) and air mixtures. The results obtained were used to create an empirical model to predict the chemical composition of coatings. Among 11 process parameters, the 3 parameters which exhibited the strongest effect on the coating composition were the torch speed, the substrate to nozzle distance and the number of scans. Auger spectroscopy revealed that the carbon content of the thin films was as low as 6 ± 1.7% and AFM analysis showed that smooth coatings (Ra ∼ 2 nm) were obtained even at high dynamic growth rates (∼1 000 nm · m · min−1). A tentative macroscopic scaling law was also formulated to correlate our results with the available literature data.

No abstract

No abstract

In this work, TiO2 films produced by rf sputtering of a TiO2 target in argon and argon–oxygen plasmas were studied. The oxygen content in the feed gas was varied in a range 3–20%. The chemical composition and structure of films were characterized by Rutherford backscattering spectrometry, x-ray photoelectron spectroscopy (XPS) and x-ray diffraction. Important information about the intrinsic defects of the films and their effects on the optical properties as well as a scheme of the energy band structure of the films could be derived from a combined use of optical spectroscopy and XPS.

Modification of polydimethylsoloxane/water interaction, to promote a spontaneous water flux through the microchannels, is a crucial task in microfluidic applications. For that reason, in this research, the authors study the hydrophilicity improvement induced by low-power oxygen plasma treatments (15 W) on the polydimethylsiloxane (PDMS) microchannel. The effects of the oxygen plasma treatments on wettability and water-work of adhesion on PDMS surfaces have been studied by sessile contact angle. The chemical composition of the plasma has been investigated by means of optical emission spectroscopy. The results indicate that the improvement of wettability on treated PDMS is led by the percentage of atomic oxygen in the plasma discharge. Super-hydrophilic surfaces (contact angle < 5°) have been obtained optimising the atomic oxygen percentage in the plasma discharge varying only the plasma working pressure. Super-hydrophilic PDMS microchannels show the highest spontaneous capillary flow in the channels while the hydrophilic microchannel shows only a small capillary flow.