1. Engineering Materials and Process Technologies : 2nd Conference of Programme Groups of the Faculty of Mechanical Engineering University of Maribor, Book of Abstracts2025 Abstract: The publication presents an overview of the research achievements of Programm Groups of the Faculty of Mechanical Engineering: P2-0424 Design of Novel Properties of (Nano)Materials & Applications, P2-0063 Design of Cellular Structures, P2-0120 Technologies of Metastable Materials, P2-0118 Textile Chemistry and Advanced Textile Materials, and P2-0196 Research in Power, Process, and Environmental Engineering from 2024 to 2025. Members of the program group present their research innovations and progress achieved within the framework of the program group's activities.
Keywords: advanced textile materials, composites, nanomaterials, biotechnology, surface functionalization and modification, cellular structures, metastable materials, power, process and environmental engineering
Published in DKUM: 03.11.2025; Views: 0; Downloads: 2
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2. Non-equilibrium plasma methods for tailoring surface properties of polyvinylidene fluoride : review and challengesAlenka Vesel, Rok Zaplotnik, Gregor Primc, Miran Mozetič, Tadeja Katan, Rupert Kargl, Tamilselvan Mohan, Karin Stana-Kleinschek, 2021, review article Abstract: Modification and functionalization of polymer surface properties is desired in numerous
applications, and a standard technique is a treatment with non-equilibrium gaseous plasma. Fluorinated polymers exhibit specific properties and are regarded as difficult to functionalize with polar
functional groups. Plasma methods for functionalization of polyvinylidene fluoride (PVDF) are
reviewed and different mechanisms involved in the surface modification are presented and explained
by the interaction of various reactive species and far ultraviolet radiation. Most authors used argon
plasma but reported various results. The discrepancy between the reported results is explained
by peculiarities of the experimental systems and illustrated by three mechanisms. More versatile
reaction mechanisms were reported by authors who used oxygen plasma for surface modification
of PVDF, while plasma sustained in other gases was rarely used. The results reported by various
authors are analyzed, and correlations are drawn where feasible. The processing parameters reported
by different authors were the gas pressure and purity, the discharge configuration and power, while
the surface finish was predominantly determined by X-ray photoelectron spectroscopy (XPS) and
static water contact angle (WCA). A reasonably good correlation was found between the surface
wettability as probed by WCA and the oxygen concentration as probed by XPS, but there is hardly
any correlation between the discharge parameters and the wettability.
Keywords: polyvinylidene fluoride, gaseous plasma, surface modification, wettability, functionalization, activation plazma
Published in DKUM: 16.06.2025; Views: 0; Downloads: 8
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3. A method for the immobilization of chitosan onto urinary cathetersAlenka Vesel, Nina Recek, Rok Zaplotnik, Albert Kurinčič, Katja Kuzmič, Lidija Fras Zemljič, 2022, original scientific article Abstract: A method for the immobilization of an antibacterial chitosan coating to polymeric urinary medical catheters is presented. The method comprises a two-step plasma-treatment procedure, followed by the deposition of chitosan from the water solution. In the first plasma step, the urinary catheter is treated with vacuum-ultraviolet radiation to break bonds in the polymer surface film and create dangling bonds, which are occupied by hydrogen atoms. In the second plasma step, polymeric catheters are treated with atomic oxygen to form oxygen-containing surface functional groups acting as binding sites for chitosan. The presence of oxygen functional groups also causes a transformation of the hydrophobic polymer surface to hydrophilic, thus enabling uniform wetting and improved adsorption of the chitosan coating. The wettability was measured by the sessile-drop method, while the surface composition and structure were measured by X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy. Non-treated samples did not exhibit successful chitosan immobilization. The effect of plasma treatment on immobilization was explained by noncovalent interactions such as electrostatic interactions and hydrogen bonds.
Keywords: polymer, chitosan immobilization, adhesion, plasma-surface modification, biopolymers
Published in DKUM: 05.12.2024; Views: 0; Downloads: 13
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5. Modification of polyamide knitted fabric using different zeolitesAlenka Ojstršek, Tomaž Fakin, Karin Stana-Kleinschek, Darinka Fakin, 2017, original scientific article Abstract: The aim of this research was to apply three different types of zeolites and the combination thereof in the form of a very fine powder, together with different chemicals and additives on polyamide knitted fabric according to an industrially acceptable exhaustion procedure in order to study changes in the morphology, optical properties and wettability of surfaces. Zeolites were analysed using Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and gas physiosorption. Additionally, the morphology of zeolite-coated surfaces was examined closely using SEM, while changes in molecular-chemical level were examined by means of IR spectroscopy. Optical properties were studied using CIE colour measurement and diff use reflectance profi le determination, while the hydrophilic/hydrophobic character was examined using goniometry. The obtained results show the suitability of the employed exhaustion procedure, depending on the type of zeolite and the composition of the treatment bath. The results also provided evidence of the enhanced wettability of PA fabrics using 4A and 13X zeolites in combination with selected additives.
Keywords: zeolites, polyamide fibres, exhaustion, surface modification, wettability
Published in DKUM: 31.08.2017; Views: 2368; Downloads: 442
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6. Protein adsorption on various plasma-treated polyethylene-terephthalate substratesNina Recek, Morana Jaganjac, Metod Kolar, Lidija Milković, Miran Mozetič, Karin Stana-Kleinschek, Alenka Vesel, 2013, original scientific article Abstract: Protein adhesion and cell response to plasma-treated polymer surfaces were studied. The polymer polyethylene terephthalate (PET) was treated in either an oxygen plasma to make the surface hydrophilic, or a tetrafluoromethane CF4 plasma to make the surface hydrophobic. The plasma source was radiofrequency (RF) discharge. The adsorption of albumin and other proteins from a cell-culture medium onto these surfaces was studied using a quartz crystal microbalance (QCM), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The cellular response to plasma-treated surfaces was studied as well using an MTT assay and scanning electron microscopy (SEM). The fastest adsorption rate was found on the hydrophilic oxygen plasma-treated sample, and the lowest was found on the pristine untreated sample. Additionally, the amount of adsorbed proteins was higher for the oxygen-plasma-treated surface, and the adsorbed layer was more viscoelastic. In addition, cell adhesion studies support this finding because the best cell adhesion was observed on oxygen-plasma-treated substrates.
Keywords: oxygen and fluorine plasma treatment, polymer surface modification, protein adsorption, cell adhesion, quartz crystal microbalance, QCM
Published in DKUM: 22.06.2017; Views: 1312; Downloads: 471
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7. Modification of PET-polymer surface by nitrogen plasmaRok Zaplotnik, Metod Kolar, Aleš Doliška, Karin Stana-Kleinschek, 2011, original scientific article Abstract: Low pressure weakly nitrogen plasma was applied for incorporation of nitrogen-containing functional groups onto poly(ethylene terephthalate) - PET polymer. Nitrogen plasma was created in an electrode-less radiofrequency discharge at the nominal power of 200 W and the frequency of 27.12 MHz. Nitrogen molecules entered the discharge region were highly excited, partially dissociated and weakly ionized. Transformation into the state of plasma allowed for creation of chemically reactive particles with a high potential energy while the kinetic energy remained close to the value typical for room temperature. The chemical reactivity allowed for rapid functionalization with nitrogen-rich functional groups. The appearance of these groups was monitored by X-ray photoelectron spectroscopy - XPS. The polymer surface was quickly saturated with nitrogen indicating that the modification was limited to an extremely thin surface film.
Keywords: poly(ethylene terephthalate), nitrogen plasma, surface modification, functional groups, X-ray photoelectron spectroscopy
Published in DKUM: 17.03.2017; Views: 1358; Downloads: 169
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8. Vpeljava in optimizacija in-vitro metode za določanje hemokompatibilnosti modificiranih polietilenteraftalnih površinJan Stana, Domen Stropnik, Simona Strnad, Tea Indest, Marko Jevšek, Gorazd Košir, 2009, original scientific article Keywords: biomaterials, poly(ethyleneterephthalate), hemocompatibility, surface modification, in-vitro method
Published in DKUM: 10.07.2015; Views: 2121; Downloads: 57
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9. Aspects of titanium-implant surface modification at the micro and nano levelsIva Milinković, Rebeka Rudolf, Karlo Raić, Zoran Aleksić, Vojkan Lazić, Aleksandar Todorović, Dragoslav Stamenković, 2012, original scientific article Abstract: The shape and chemical composition, as well as the macro- and microtopography, of an implant surface have been studied widely as the major factors that positively influence implant osseointegration. Titanium and titanium alloys have been used extensively over the past 20 years as biomedical materials in orthopedic and dental surgery because of their good mechanical properties, corrosion resistance, no cell toxicity, and very poor inflammatory response in peri-implant tissue, which confirms their high biocompatibility. Their favorable biological performance is attributed to a thin native oxide film that forms spontaneously on the titanium surface. It is well established that surface roughness plays an important role in implant fixation. Accordingly, some authors have indicated the existence of an optimal range of surface roughness. The titanium surface can be either chemically or physically modified, or both, in order to improve biomaterial-tissue integration. Different treatments are used to modify the titanium surface. Hydroxyapatite coatings, preceded or not by acid etching, are used to create a rough, potentially bioactive surface. Oxide blasting treatments, either with or without chemical etching, are used to develop roughsurfaces. Thick oxide films obtained by anodic or thermal oxidation have been used to accelerate the osseointegration process. The ideal microtopography of the surface is still unknown, however, because it is very difficult to associate surface properties with clinical results. As more accurate knowledge is required, several Ti surfaces have been analyzed and the endosseous implant surface modified on the micro level has been thoroughly studied. Additionally, the production of gold (Au) nanoparticles to be added to the micron-scale modified surface has been performed. In this respect, an appropriate overview of our results is given.
Keywords: Ti implant, Au nanoparticles titan alloys, surface modification, microstructure
Published in DKUM: 10.07.2015; Views: 1658; Downloads: 116
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