Papers by Veronica Satulu
International Journal of Molecular Sciences
Despite the technological progress of the last decade, dental caries is still the most frequent o... more Despite the technological progress of the last decade, dental caries is still the most frequent oral health threat in children and adults alike. Such a condition has multiple triggers and is caused mainly by enamel degradation under the acidic attack of microbial cells, which compose the biofilm of the dental plaque. The biofilm of the dental plaque is a multispecific microbial consortium that periodically develops on mammalian teeth. It can be partially removed through mechanical forces by individual brushing or in specialized oral care facilities. Inhibition of microbial attachment and biofilm formation, as well as methods to strengthen dental enamel to microbial attack, represent the key factors in caries prevention. The purpose of this study was to elaborate a cold plasma-based method in order to modulate microbial attachment and biofilm formation and to improve the retention of fluoride (F−) in an enamel-like hydroxyapatite (HAP) model sample. Our results showed improved F rete...
Nuclear Materials and Energy, 2022
Materials Research Express, 2020
2008 23rd International Symposium on Discharges and Electrical Insulation in Vacuum, 2008
In this contribution we report on plasma modification of natural textile fibres, like raw wool an... more In this contribution we report on plasma modification of natural textile fibres, like raw wool and wool yarn and cotton wool and cotton yarn. Radiofrequency plasmas (13.56 MHz) generated in parallel plate configuration at low pressure and in dielectric barrier discharge (DBD) configuration at atmospheric pressure have been used. At low pressure the samples were treated at different times (1-30
Plasma Processes and Polymers, 2009
ABSTRACT The effect of plasma treatment on the properties of poly(ethylene terephthalate) track m... more ABSTRACT The effect of plasma treatment on the properties of poly(ethylene terephthalate) track membranes has been investigated. The influence of plasma treatment conditions and composition of plasma-forming gas on basic membrane characteristics–pore size and shape, wettability, hydrodynamic, and electrochemical properties–were studied. It is shown that the plasma treatment of membranes can significantly improve their performance characteristics and give them a lot of useful properties.
Russian Journal of Electrochemistry, 2011
The structure and electrochemical properties of polyethylene terephthalate track membranes modifi... more The structure and electrochemical properties of polyethylene terephthalate track membranes modified in acetylene plasma are studied. It is found that polymer deposition on the track membrane surface using acetylene polymerization in plasma results in the case of formation of a semipermeable layer covering pores in formation of a composite nanomembrane featuring asymmetry of conductivity in solutions of electrolytes: a rectifying
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2010
The structure and the charge transport properties of poly(ethylene terephthalate) track membrane ... more The structure and the charge transport properties of poly(ethylene terephthalate) track membrane modified by pyrrole plasma were studied. It was found that polymer deposition on the surface of a track membrane via plasma polymerization of pyrrole results in the creation of composite nanomembranes that, in the case of the formation of a semipermeable layer, possess asymmetric conductivity in electrolyte solutions
High Energy Chemistry, 2008
ABSTRACT The structure and the charge transport properties of poly(ethylene terephthalate) track ... more ABSTRACT The structure and the charge transport properties of poly(ethylene terephthalate) track membranes modified in a thiophene plasma were studied. It was found that polymer deposition on the surface of a track membrane via the plasma polymerization of thiophene results in composite membranes that, in the case of the formation of a semipermeable layer, exhibit conductivity asymmetry—rectifying effect—in electrolyte solutions. It was shown that chemical doping with iodine or photo-oxidation of the polymer layer produced in plasma leads to alteration in the electrochemical properties of plasma-modified membranes.
Polymers, 2022
In the field of bioengineering, depending on the required application, the attachment of various ... more In the field of bioengineering, depending on the required application, the attachment of various biological entities to the biomaterial is either favored or needs to be prevented. Therefore, different surfaces modification strategies were developed in combination with the characteristics of the materials. The present contribution reports on the use of the specific surface property of a thermoresponsive polymer poly(N-isopropylacrylamide) pNIPAAM obtained by spin coating in combination with plasma treatment for tuning cell behavior on treated polymeric surfaces. Topographical information for the plasma-treated pNIPAAM coatings obtained by Atomic Force Microscopy (AFM) measurements evidenced a more compact surface for Ar treatment due to combined etching and redeposition, while for oxygen, a clear increase of pores diameter is noticed. The chemical surface composition as determined by X-ray Photoelectron Spectroscopy showed the specific modifications induced by plasma treatment, namel...
ABSTRACT Plasma polymerization has been carried out in a parallel plate RF discharge reactor in m... more ABSTRACT Plasma polymerization has been carried out in a parallel plate RF discharge reactor in mixtures of argon with pentacyclic precursors, namely thiophene, furan and pyrrole. The plasma characterization showed the presence of emission bands peculiar to each monomer. The deposition of highly transparent films with partial conservation of the pentacyclic structure, inclusion of various oligomers, roughness and surface energy depending on the precursor nature was demonstrated by material investigations results. The material conductivity is significantly improved upon iodine doping in the case of polythiophene and polypyrrole-like films, while an opposite behavior was observed for the polyfuran-like films.
Nanocomposite materials based on metallic particles embedded in insulating matrices have been ext... more Nanocomposite materials based on metallic particles embedded in insulating matrices have been extensively studied during the last decades due to their interesting optical, electrical and biomedical properties. Among the widely used synthesis methods are those based on plasma techniques. In the present contribution we report on the preparation of Cu – siloxane composites in a hybrid PVD/PECVD system, and their characterization. The deposition is taking place in a stainless steel cylindrical reactor provided with two plasma sources mounted perpendicular one on each other, and oriented at 45° in respect to the grounded substrate holder. The PECVD plasma is generated at 20 W RF power in a mixture of Ar/HMDSO injected through the active electrode, while the magnetron sputtering plasma with copper target is ignited in Ar at 100 W. The substrate is sequentially exposed for 60 s to the plasma polymerization step and, respectively, for 60 s, to the metallic deposition step. The plasma specie...
International Journal of Molecular Sciences
A series of coatings from poly(ethylene-co-vinyl acetate) (EVA) were obtained using the matrix-as... more A series of coatings from poly(ethylene-co-vinyl acetate) (EVA) were obtained using the matrix-assisted pulsed laser evaporation (MAPLE) technique. By changing the process parameters, i.e., laser fluence and EVA co-polymer concentration in the target, coatings with various morphologies and topographies were produced. The evaluation of the film structure was based on an analysis of optical and atomic force microscopy and profilometry measurements. A detailed chemical structure investigation, conducted based on Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) spectra, revealed that although the general structure was preserved, some alterations of ethylene (Et) and vinyl acetate (VAc) blocks took place. The most noticeable change was in the ester group that was transformed into ketone and carboxyl groups; nevertheless, some changes in the aliphatic main chain were also present. The chemical structure changes in EVA coatings took place regardless of the proce...
Applied Sciences
Tungsten erosion and dust occurrence are phenomena of great interest for fusion technology. Herei... more Tungsten erosion and dust occurrence are phenomena of great interest for fusion technology. Herein, we report results concerning the material damage and dust formation in the presence of high temperature and large area or concentrated discharges in helium and argon. In order to generate adequate plasmas, we used tungsten electrodes in two experimental discharge systems, namely a hollow discharge and a microjet discharge. In both exposure cases, we noticed surface modification, which was assigned to sputtering, melting, and vaporization processes, and a significant dust presence. We report the formation on electrode surfaces of tungsten fuzz, nano-cones, nanofibers, and cauliflower- and faced-like particles, depending on the discharge and gas type. Dust with various morphologies and sizes was collected and analyzed with respect to the morphology, size distribution, and chemical composition. We noticed, with respect to erosion and particle formation, common behaviors of W in both labo...
Journal of Physics D: Applied Physics
Scientific Reports
Submerged liquid plasma (SLP) is a new and promising method to modify powder materials. Up to now... more Submerged liquid plasma (SLP) is a new and promising method to modify powder materials. Up to now, this technique has been mostly applied to carbonaceous materials, however, SLP shows great potential as a low-cost and environmental-friendly method to modify cellulose. In this work we demonstrate the modification of microcrystalline cellulose (MCC) by applying the SLP combined with ultrasonication treatments. The plasma generated either in an inert (argon) or reactive (argon: oxygen or argon:nitrogen) gas was used in MCC dispersions in water or acetonitrile:water mixtures. An enhanced defibrillation of MCC has been observed following the application of SLP. Furthermore, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy have been applied to investigate the surface functionalization of MCC with oxygen or nitrogen moieties. Depending on the plasma treatment applied, poly (3-hydroxybutyrate) composites fabricated with the plasma modified cellulose fibers showed better thermal stability and mechanical properties than pristine PHB. This submerged liquid plasma processing method offers a unique approach for the activation of cellulose for defibrillation and functionalization, aiming towards an improved reinforcing ability of biopolymers.
High Temperature Material Processes: An International Quarterly of High-Technology Plasma Processes
Molecules, 2016
Using plasma in conjunction with fluorinated compounds is widely encountered in material processi... more Using plasma in conjunction with fluorinated compounds is widely encountered in material processing. We discuss several plasma techniques for surface fluorination: deposition of fluorocarbon thin films either by magnetron sputtering of polytetrafluoroethylene targets, or by plasma-assisted chemical vapor deposition using tetrafluoroethane as a precursor, and modification of carbon nanowalls by plasma treatment in a sulphur hexafluoride environment. We showed that conformal fluorinated thin films can be obtained and, according to the initial surface properties, superhydrophobic surfaces can be achieved.
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Papers by Veronica Satulu