Riccardo d'Agostino

Selective grafting of amine groups on polyethylene by means of NH3−H2 RF glow discharges

Plasma treatments in Radio Frequency Glow Discharges fed with NH3−H2 mixtures have been performed for modifying polyethylene surfaces. Treatment kinetics and the role of species present in the glow have been investigated. Actinometric Optical Emission Spectroscopy has been utilized as a plasma diagnostic technique. Electron Spectroscopy for Chemical Analysis has been utilized for studying surface composition of treated substrates, which have been examined both astreated and after derivatization of amine-functionalities with 4-trifluoromethylbenzaldehyde vapors. It has been found that experimental plasma parameters and plasma density of active species can be controlled to achieve selective grafting of-NH2 among all other nitrogen-containing groups.

Nanotexturing of Polystyrene Surface in Fluorocarbon Plasmas: From Sticky to Slippery Superhydrophobicity

In this work plasma etching processes have been studied to roughen and fluorinate polystyrene surface as an easy method to achieve a superhydrophobic slippery character. Radiofrequency discharges have been fed with CF(4)/O(2) mixtures and the effect of the O(2):CF(4) ratio, the input power, and the treatment duration have been investigated in terms of wettability, with focus on sliding performances. For this purpose, surface morphological variations, evaluated by means of scanning electron microscopy and atomic force microscopy, together with the chemical assessment by X-ray photoelectron spectroscopy, have been correlated with water contact angle hysteresis and volume resolved sliding angle measurements. Results indicate that by increasing the height and decreasing the density of the structures formed by etching, within a tailored range, a transition from sticky to slippery superhydrophobicity occurs. A short treatment time (5 min) is sufficient to obtain such an effect, provided that a high power input is utilized. Optimized surfaces show a unaltered transparency to visible light according to the low roughness produced.

Deposition of super-hydrophobic fluorocarbon coatings in modulated RF glow discharges

Superhydrophobic coatings were deposited in modulated RF glow discharges fed with tetrafluorothylene. Such coatings are characterized by a high fluorination degree, ribbon-like randomly distributed surface microstructures, and a certain crystallinity. Combined high fluorination degree and surface texture/roughness leads to the super hydrophobic behaviour, as attested by water contact angle values of 150° and more. The coatings were characterized by means of XPS, FT-IR and X-ray diffraction, while time resolved optical emission spectroscopy was utilized to investigate the plasma phase.

Diagnostics and decomposition mechanism in radio-frequency discharges of fluorocarbons utilized for plasma etching or polymerization

Optical emission (180–800 nm) and mass spectroscopy have been used to study the CF4, CF4+O2, C2F6, C2F6+H2, CF3Cl, and C2F4 decomposition in radio-frequency discharges. The analysis of the stable and unstable discharge products has allowed the suggestion of decomposition channels for the various gases and to classify the fluorinated gases according to their predominant etching or polymerizing characteristics on the basis of the active species present in the plasma. A new broad emission continuum centered at λ=290 nm (FWHM=66 nm) has also been identified and it has been tentatively assigned to CF+2.

Plasma‐Enhanced Chemical Vapor Deposition of Organosilicon Thin Films from Tetraethoxysilane‐Oxygen Feeds

The composition of films deposited in RF glow discharges fed with tetraethoxysilane and oxygen mixtures has been investigated by means of in situ x-ray photoelectron spectroscopy and infrared spectroscopy. These results, combined with mass spectrometric investigations of the gas phase, indicate that the overall deposition consists of several concurrent heterogeneous and homogeneous reactions

Application of plasma deposited organosilicon thin films for the corrosion protection of metals

In this contribution it will be shown that plasma enhanced chemical vapor deposition (PECVD) of silicon containing organic compounds is a promising approach for the corrosion protection of metals (steel and magnesium alloys). When the deposition process is preceded by a suitable plasma treatment, which depends on the particular metal under study, a marked increase of the protective properties measured with electrochemical impedance spectroscopy (EIS) is detected. The highest impedance modulus obtained for Mg is 450 KΩ·cm2, 8000 times higher than for the bare metal. Highly protective coatings are obtained for inorganic films, free of sylanols. A marked decrease of the impedance modulus of coated substrates has been registered after immersion in electrolyte solution due to the presence of pinholes which represents defect points where localized corrosion starts.

Morphological and structural study of plasma deposited fluorocarbon films at different thicknesses

The growth of fluorocarbon thin films has been obtained by continuous and modulated r.f. plasmas fed with C2F4. The kinetics surface morphology of the coatings has been investigated and analyzed on films of various thicknesses. Such a study has allowed the evolution of structures in size and shape to be followed. Specifically, it has been observed that modulated plasmas with the proper duty cycles (⩽7%) lead to the formation of micrometer-long ribbon-shaped nanostructures. The precursors of the ribbons are nuclei that align into a spiral-mimic. Highly nanostructured films with an optimal thickness and ribbon density exhibit a super-water repellent surface with contact angles up to 170°. The surface roughness and smoothing of fluorocarbon films are strongly affected by the modulated and continuous plasmas, respectively.

Rf plasma deposition of SiO2-like films : plasma phase diagnostics and gas barrier film properties optimisation

Hexamethyldisiloxane/oxygen fed radiofrequency glow discharges have been utilised for the deposition onto polyethyleneterephtalate of transparent silicon dioxide-like films with barrier properties to oxygen. The complexity of such plasma phases and the increasing interest shown for the industrial deposition process of barrier films have led the authors to investigate Fourier transform infrared absorption spectroscopy as a plasma technique for better understanding of the deposition mechanism and the development of a process control useful for scaling up. The above mentioned technique has shown its potential in the correlation of plasma phase chemistry with the barrier properties of the SiOx coated polymer, especially when very good performances are required (OTR≤3 cm3/m2 day atm).

Polymer film formation in C2F6H2 discharges

Abstract Thin fluoropolymer films deposited in an r.f. discharge fed with C 2 F 6 H 2 mixtures were studied. The effect of the electrical characteristics, the substrate temperature and the feed composition on both the chemical structure of the film and on the growth mechanism were analysed. It was found, in particular, that the structure of the film is affected by the H 2 concentration in the feed and by the discharge voltage and current values and that the polymerization rate decreases with temperature after a threshold.

Advanced plasma technology

Basic Approaches to Plasma Production and Control N. Sato Plasma Sources and Reactor Configurations P. Colpo Simulations for Low-Temperature Plasma Applications J. K. Lee Modeling and diagnostics of He discharges for treatment of polymers D. Mataras 3-D Modelling of Thermal Plasmas (RF and Transferred Arc) for the Design of Sources and Industrial Processes E. Ghedini RF Plasma Sources for Semiconductor processing F. F. Chen Advanced Plasma Diagnostics for Thin Film Deposition R. Engeln Plasma Processing of Polymers by a Low-Frequency Discharge with Asymmetrical Configuration of Electrodes F. Arefi-Khonsari and M. Tatoulian Fundamentals on plasma deposition of fluorocarbon films A. Milella Plasma CVD processes for thin film Si solar cells A. Matsuda VHF Plasma Production for Solar Cells Y. Kawai Growth Control of Clusters in Reactive Plasmas and Its Application to High-stability a-Si Film Deposition Y. Watanabe Micro- and Nano-Structuring in Plasma-Processes for Biomaterials: Micro- and Nano-Features as Powerful Tools to Address Selective Biological Responses E. Sardella Chemical Immobilization of Biomolecules on Plasma Modified Substrates for Biomedical Applications L. C. Lopez In Vitro Methods to Assess the Biocompatibility of Plasma Modified Surfaces M. Nardulli Cold gas plasma in biology and medicine E. Stoffels Mechanisms of Sterilization and Decontamination of Surfaces by Low Pressure Plasma F. Rossi Application to Atmospheric Pressure Glow Plasma M. Kogoma Hydrocarbon and fluorocarbon thin films deposition in atmospheric pressure glow dielectric barrier discharges F. Fanelli Remark on Production of Atmospheric Pressure Non-Thermal Plasmas for Modern Application R. Itatani Present status and Future of Color Plasma Display T. Shinoda Characteristics of PDP Plasmas H. Ikegami Recent progress in plasma spray processing T. Yoshida Electrohydraulic Discharge Direct Plasma Water Treatment Processes J.-S. Chang Development and Physics Issues of an Advanced Space Propulsion M. Inutake