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An extensive analysis of iron–nitrogen-carbon (Fe–N–C) electrocatalysts synthesis and activity is presented concerning synthesis conditions such as initial Fe content, pyrolysis temperature and atmosphere (inert N2, reducing NH3, oxidizing Cl2 and their sequential combinations) and the influence of an external magnetic field on their performance in oxygen reduction reaction (ORR). Thermosetting porous polymers doped with FeCl3 were utilized as the Fe–N–C catalysts precursors. The pyrolysis temperature was varied within a 700–900 °C range. The temperature and atmosphere of pyrolysis strongly affect the porosity and composition of the resultant Fe–N–C catalysts, while the initial amount of Fe precursor shows much weaker impact. Pyrolysis under NH3 yields materials similar to those pyrolyzed under an inert atmosphere (N2). In contrast, pyrolysis under Cl2 yields carbon of peculiar character with highly disordered structure and extensive microporosity. The application of a static external magnetic field strongly enhances the ORR process (herein studied in an alkaline environment) and the enhancement correlates with the Fe content in the Fe–N–C catalysts. The Fe–N–C materials containing ferromagnetic iron phase embedded in N-doped microporous carbon constitute attractive catalysts for magnetic field-aided anion exchange membrane fuel cell technology.

Polyurethane coatings containing copper(II) L-tyrosine and glass microspheres were laser irradiated and underwent electroless metallization. Various sizes of glass microspheres were incorporated into the polyurethane coating matrix in order to examine their effects on surface activation and electroless metallization. The surface of the coatings was activated by using ArF excimer laser emitting ultraviolet radiation (λ = 193 nm) using different number of laser pulses and their fluence. The effects of surface activation and metallization were evaluated mainly based on optical and scanning electron microcopies (SEM), energy-dispersive X-ray spectroscopy (EDX) and photoelectron spectroscopy (XPS). It was found that the presence of glass microspheres enabled the reduction in copper complex content, intensified the ablation process (higher cone-like structures created) and resulted in higher content of copper metallic seeds. On the other hand, the glass microspheres concentration, which was higher for lower size microspheres, was advantageous for obtaining a fully metallized layer.

In this work, low-temperature photoionized plasma, induced in N2 by extreme ultraviolet (EUV) pulses, was used for surface modification of poly(L-lactic acid) (PLLA). Polymer samples were irradiated with 100, 200, and 300 pulses at a 10 Hz repetition rate. The physical and chemical properties of PLLA samples were examined using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The human dermal fibroblast adult cells (NHDF-Ad) were used for the cell culture and viability tests on modified PLLA surfaces. The N2-plasma and EUV treatment caused alteration of the surface morphology resulting in increased surface roughness, incorporation of nitrogen atoms, and appearing of new functional groups on the surface. Cell culture results showed an increase in the number of fibroblasts attached to the modified surfaces compared to the pristine PLLA. The modified surfaces demonstrated high cell viability and no cytotoxic effects were observed.

The morphology and chemical composition of platinum coatings deposited by magnetron-ion sputtering of a platinum target in various modes (stationary, pulsed), and air spraying of platinum black on titanium supporting foils were studied. Metallic platinum subjected to ionic purification was used as a reference sample. It is shown that the composition of coatings in addition to platinum includes its oxides PtO (10–11 at. %) and PtO2 (2–5 at. %). The presence of oxides in the composition of platinum coatings is explained by the high specific surface of platinum in the coating, whereby partial oxidation takes place in the air. It has been found that the mode of magnetron-ion sputtering, as well as the presence of the Nafion® ionomer (5 wt. %) in the air-spraying composition based on platinum black does not affect the phase composition of the coating. Morphological properties of the platinum coatings are influenced by the state of initial platinum source, and by the energy of the sputtered particles.

Surface-enhanced Raman spectroscopy (SERS) is a very promising analytical technique for the detection and identification of trace amounts of analytes. Among the many substrates used in SERS of great interest are nanostructures fabricated using physical methods, such as semicontinuous metal films obtained via electron beam physical vapor deposition. In these studies, we investigate the influence of morphology of semicontinuous silver films on their SERS properties. The morphologies studied ranged from isolated particles through percolated films to almost continuous films. We found that films below the percolation threshold (transition from dielectric-like to metal-like) made of isolated silver structures provided the largest SERS enhancement of 4-aminothiophenol (4-ATP) analyte signals. The substrate closest to the percolation threshold has the SERS signal about four times lower than the highest signal sample.

Polyetheretherketone (PEEK), due to its excellent mechanical and physico-chemical parameters, is an attractive substitute for hard tissues in orthopedic applications. However, PEEK is hydrophobic and lacks surface-active functional groups promoting cell adhesion. Therefore, the PEEK surface must be modified in order to improve its cytocompatibility. In this work, extreme ultraviolet (EUV) radiation and two low-temperature, EUV induced, oxygen and nitrogen plasmas were used for surface modification of polyetheretherketone. Polymer samples were irradiated with 100, 150, and 200 pulses at a 10 Hz repetition rate. The physical and chemical properties of EUV and plasma modified PEEK surfaces, such as changes of the surface topography, chemical composition, and wettability, were examined using atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and goniometry. The human osteoblast-like MG63 cells were used for the analysis of cell viability and cell adhesion on all modified PEEK surfaces. EUV radiation and two types of plasma treatment led to significant changes in surface topography of PEEK, increasing surface roughness and formation of conical structures. Additionally, significant changes in the chemical composition were found and were manifested with the appearance of new functional groups, incorporation of nitrogen atoms up to ~12.3 at.% (when modified in the presence of nitrogen), and doubling the oxygen content up to ~25.7 at.% (when modified in the presence of oxygen), compared to non-modified PEEK. All chemically and physically changed surfaces demonstrated cyto-compatible and non-cytotoxic properties, an enhancement of MG63 cell adhesion was also observed.

In this work, the effect of extreme ultraviolet (EUV) radiation and the combination of EUV radiation and low-temperature nitrogen plasma on the physico-chemical properties of polyetheretherketone (PEEK) surfaces were presented. The laser-plasma EUV source based on a double gas puff target was used in this experiment to irradiate PEEK surfaces with nanosecond pulses of EUV radiation and to produce low-temperature plasma through the photoionization of nitrogen with EUV photons. The changes in surface morphology on irradiated polymer samples were examined using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Chemical changes of the PEEK surfaces were analysed using X-ray photoelectron spectroscopy (XPS). EUV radiation and nitrogen plasma treatment caused significant changes in the topography of modified PEEK&rsquo, s surfaces and an increase in their average roughness. Strong chemical decomposition, appearance of new functional groups as well as incorporation of nitrogen atoms up to ~17 at.% on the PEEK&rsquo, s surface were observed.

Raman spectroscopy has become an essential analytical technique for field detection and identification of illicit or dangerous materials such as explosives, but its main drawback is low signal intensity. This problem can be circumvented by using surface enhanced Raman spectroscopy (SERS), in which scattering signals increase significantly for analytes adsorbed onto or near nanostructured surfaces of the plasmonic materials. However, despite numerous studies, SERS has still not been widely used in real-world applications. The main goal of the studies describe herein was to investigate the possibility of detection of trace amounts of selected explosive materials on various commercial and non-commercial SERS substrates using portable Raman instruments. Our studies have shown that while portable systems suitable for SERS measurement of trace amounts of explosives are readily available, the problem remains in the selection of reliable and reproducible SERS substrates. Among five investigated SERS substrates only two, Klarite 312 and GaN-pillars allowed for trace analysis of all studied explosive materials. In both cases, detected concentrations of explosives ranged from single to hundreds of μg/cm2 depending on the explosive material and the Raman spectrometer used. Based on our findings, it could be concluded that the best SERS substrates for trace analysis of explosives are substrates with hot spots densely and evenly distributed over a whole active area of SERS substrate.

The outstanding properties of carbon materials doped with p-block elements are usually attributed directly to the presence of certain foreign atoms. By using the example of selenium-doped carbon gels, we hereby postulate that in many cases the properties of doped carbon materials are not determined by the presence of the heteroatom itself, but rather by how the element affects the carbon structure during high-temperature synthesis. Se-doped microporous carbogels were obtained via sol-gel polycondensation of resorcinol and 2-formylselenophene followed by pyrolysis at 600–1200 °C. Pyrolysis temperatures above 800 °C result in a decrease in the Se-content accompanied by a distinct increase in ultramicroporosity. A comparative analysis of oxygen-, sulfur- and selenium-doped carbogels shows that chalcogens increase the porosity of carbonaceous materials via the high-temperature oxidation of carbon to corresponding dichalcogenides (CO2, CS2 or CSe2), but their oxidative power diminishes with increasing atomic mass. Consequently, S and Se are more selective carbon oxidants.

The Turkevich method, in which citrate reduces chloroauric acid, is one of the most popular and standard protocols for the synthesis of gold nanoparticles. Mechanistic studies for this reduction have shown that reducing and capping capabilities of citrate are associated with its structure and particularly with the hydroxyl group attached to the α-position of the carboxyl group. Hence, it should be possible to synthesize gold nanoparticles with similar characteristics upon substitution of citrate by the other α-hydroxycarboxylates. Various α-and β-hydroxycarboxylates have been used to investigate the effect of citrate substitution on reaction outcome. The shape, size distribution, stability and optical properties of gold nanoparticles were characterized by scanning and transmission electron microscopy, differential centrifugal sedimentation and UV–vis spectroscopy. The citrate can be substituted in the Turkevich method by other α-hydroxycarboxylates, however, their structure and the first product of their oxidation strongly influence shape, size and size distribution of synthesized gold nanoparticles. The α-position of the hydroxyl group with respect to the carboxyl group is critical for the reduction to occur. These comprehensive studies provide new insights into the reaction mechanism governing the Turkevich method.

Polylactide (PLA) composites containing flax fibre strands (20 wt%) and various content of triallyl isocyanurate (TAIC) as crosslinking agent were prepared by extrusion and injection moulding processes. The composites were modified by electron beam (EB) irradiation at dose values of 0, 10, 20, 30 and 40 kGy. The effects of EB and TAIC on the mechanical and structural properties of the composites were studied using tensile and impact tests, dynamic mechanical analysis (DMA), gel fraction measurement, differential scanning calorimetriy (DSC) and thermogravimetry (TG). However, the main attention was paid to biodegradation effects. Composites were biodegraded by means of enzymatic treatment and industrial composting. The composites were examined using mass loss analysis, DSC and photoelectron spectroscopy (XPS) in order to determine structural changes induced by biodegradation. Application of TAIC and EB at dose of 40 kGy led to the increase of tensile strength of about 20%. Besides crosslinking branching of PLA macromolecules was of significant importance. EB irradiation intensified enzymatic and composting degradation, however, when TAIC was applied, the composite was much more resistant to these processes.

Self-aligned and equal-space SnO2 nanotubes (NTs) with external diameters ranging from ca. 124 to ca. 325 nm and wall thickness of around 30 nm were synthesized by AAO template-assisted atomic layer deposition. The bulk and surface structure of the SnO2 nanostructures were studied in detail by XRD and XPS techniques, respectively. The SnO2 NTs were polycrystalline with an average crystallite size of ca. 3 nm. The structure analysis has revealed that the SnO2 NTs are composed of the rutile-type SnO2. The SnO2 nanotube arrays with the smaller external diameters emitted green light centered at around 520 nm. The emission was ascribed to the radiative recombination between electrons trapped in shallow donor levels and holes at the intrinsic surface states, associated with the oxygen deficient sites near surface region. The PL intensity diminished with the nanotube diameter and spacing. With increasing external diameter of the SnO2 nanotubes and decreasing the distance between the neighboring nanotubes, the emission become progressively weaker. The results demonstrate that the structure, morphology and arrangement of SnO2 nanotubes play an important role in their luminescent properties.

(Co)polycondensation of resorcinol and heterocyclic aldehydes yields heteroaromatic porous polymers. Carbonization of such polymers results in N-doped, S-doped, N/S-co-doped or undoped carbon gels depending on the starting composition of reactants. If the (co)polycondensation is initiated with FeCl3, Fe-containing carbon gels are obtained. Depending on the nature of the heteroatom doping (solely N or S, both N and S or no heteroatom) the Fe-containing carbon gels exhibit distinct structural properties. While the presence of sulfur hinders Fe-driven graphitization, yielding carbons with high specific surface area (SSA), N-doping exhibits the contrary effect, resulting in highly graphitic structures with low SSAs. More importantly, increasing the Fe content in the N/S-co-doped carbons results in remarkable increases in microporosity, yielding materials with SSA of up to 1240 m2g-1. The Fe-containing carbon gels are considered non-precious metal catalysts for the oxygen reduction reaction. It is demonstrated that in the case of Fe/N/C/S type catalysts, the interaction between S, C and Fe (at the pyrolysis stage) results in the enhancement of microporosity, where S acts as a soft oxidant toward carbon, while Fe recaptures the sulfur- and carbon-containing pyrolytic gases. The incidental deposition of pyrolytic gases contributes significantly to the final structure of the catalysts.

The aim of present study was to determine the hemocompatibility, cellular response of endothelial cells and bacterial adhesion to a new polyester nanocomposite. The carbon nanoparticle nanocomposite was prepared via in situ polymerization of monomers to obtain material of hardness 55 Sh D similar to polyurethanes used in medical applications, for example, in heart-assisting devices. The carbon nanoparticle-containing polyester exhibits markedly reduced bacterial colonization, as compared to commercially available polyurethanes. Further the nanocomposite possesses markedly improved hemocompatibility, as determined by flow cytometry, and robust endothelialization. Possible explanations for these beneficial properties include surface nanoroughness of carbon nanoparticle-containing nanocomposites and presence of fatty acid sequences within polymer structure.

Self-aligned and equal-spaced zinc oxide (ZnO) nanotube arrays were fabricated with anodic aluminum oxide (AAO)-assisted growth and the ALD technique. The near band-edge (NBE) emission was strongly affected by the nanotube's geometrical parameters, such as a packing density and thickness of the nanotube walls. The NBE emission was further enhanced with Al2O3 coating. The effect was analyzed by X-ray photoelectron spectroscopy (XPS) and ascribed to the surface defect passivation and a ZnAl2O4 spinel formation. The NBE emission enhancement was greater in ZnO nanotubes with thicker walls. A smaller UV enhancement factor was explained by less uniform and integral Al2O3 coverage of the ZnO nanotubes with thinner walls; this, possibly induced a variation of the Al2O3 refractive index along the nanotubes. As a result, the optical conditions at the ZnO/Al2O3/air interfaces was changed and the light extraction efficiency was reduced in the latter samples.

Inorganic hollow spheres find a growing number of applications in many fields, including catalysis and solar cells. Hence, a simple fabrication method with a low number of simple steps is desired, which would allow for good control over the structural features and physicochemical properties of titania hollow spheres modified with noble metal nanoparticles. A simple method employing sol–gel coating of nanoparticles with titania followed by controlled silver diffusion was developed and applied for the synthesis of Ag-modified hollow TiO2 spheres. The morphology of the synthesized structures and their chemical composition was investigated using SEM and X-ray photoelectron spectroscopy, respectively. The optical properties of the synthesized structures were characterized using UV–vis spectroscopy. Ag–TiO2 hollow nanostructures with different optical properties were prepared simply by a change of the annealing time in the last fabrication step. The synthesized nanostructures exhibit a broadband optical absorption in the UV–vis range.

A range of heteroatom-doped carbon gels was studied to identify factors determining the efficiency of oxidative and adsorptive degradation/removal of phenolic compounds from aqueous solutions. Carbon xerogels were obtained via pyrolysis of resorcinol-heterocyclic aldehyde thermosetting resins. By utilizing either nitrogen-, sulfur- or oxygen-bearing heterocycles and impregnating the resins with FeCl3, carbons doped with the selected heteroatoms (N, S, O) and Fe could be obtained. This synthetic approach allows precise control of the doped element(s) amount and type. The efficiency of the chlorophenol removal process was correlated with the texture of the obtained carbon gels (for adsorptive removal), the pH of an aqueous solution and the H2O2 concentration (for oxidative degradation). The coexistence of iron and nitrogen within porous carbons enhances their catalytic properties towards oxidative decomposition of organic compounds via H2O2 activation, while the adsorption capacity for chlorophenols is directly correlated with microporosity and specific surface area values. The extensive mesoporosity and graphitic structure of the Fe and N co doped carbons result in efficient oxidative decomposition of the model organic pollutants. Sulfur doping prevented Fe-assisted graphitization during pyrolysis yielding disordered and highly microporous S and Fe co doped materials. The extent of oxidative degradation of chlorophenols decreased with an increasing number of Cl atoms in the phenolic ring. This report shows that Fe and N co doped carbons (the so-called Fe N C pyrolyzed materials) are more active heterogeneous catalysts for oxidative (chloro)phenol degradation than their nitrogen- and/or iron-free counterparts, showing the importance of simultaneous coexistence of both elements (Fe and N) in the carbon scaffold.

The paper presents the results of laser modification as a method of surface layer preparation to autocatalytic metallization of polylactide. Laser modification was performed using an ArF excimer laser with a fluence of 15, 30 or 60 mJ/cm2. The number of 10, 50, 100, 500 and 1000 laser pulses were used. The effects of laser modification on the geometrical structure, surface wettability, surface energy and chemical composition of polylactide surface layer have been studied. Copper plating was conducted to determine the effectiveness of laser modification as a surface preparation method prior autocatalytic metallization. Studies have shown that the best quality of copper layer was obtained for a sample modified with 10 laser pulses with fluence of 15 mJ/cm2. For the remaining samples modified with higher laser fluence or more pulses deposited layers were inferior quality or did not deposit at all.

The use of biodegradable polymers derived from renewable sources may in the future be a solution to the problem of environmental pollution with polymer waste. By using natural fillers and additives in addition to the biodegradable matrix, we are able to obtain truly eco-fiendly green materials. The paper presents the result of selected properties of polylactide films containing natural coffee, cocoa or cinnamon extracts which primarily were proposed as natural antioxidants. The focus was on properties relevant to the packaging industry such as color and transparency, surface roughness, wettability, surface energy, friction coefficient, adhesion strength and gas permeability. It was found that the extracts used at the appropriate contents have a beneficial effect on the studied properties. The obtained results were often better not only than the values ​​obtained for pure polymer, but also better than the values ​​obtained for the film containing a synthetic anti-aging compound. It can therefore be concluded that the proposed plant extracts have a positive effect not only on the aging resistance of polylactide, but also other properties of this polymer. They can be therefore an alternative to synthetic additives.

Surface modification of polymers is often required to make the material suitable for specific application. Physical and chemical properties can be altered using a number of well developed techniques, such as plasma treatment, excimer lasers, chemical treatment, surface coating, plasma immersion ion implantation-deposition and laser surface structuring. Extreme ultraviolet radiations have limited penetration depth as they are readily absorbed even in low dense medium. However, their interaction with polymer surfaces is very strong due to high energy level of these photons. Therefore, EUV photons can be used to induce surface modifications in the polymer surfaces. This study is focused on the use of EUV photons for chemical surface modification of Polyethylene terephthalate (PET) films to incorporate nitrogen atoms. Nitrogen doping is often desirable in biomaterials to enhance the biocompatibility. EUV treated PET films in the presence of nitrogen and helium environments were studied using X-ray photoelectron spectroscopy (XPS) to examine the EUV induce chemical modifications.Surface modification of polymers is often required to make the material suitable for specific application. Physical and chemical properties can be altered using a number of well developed techniques, such as plasma treatment, excimer lasers, chemical treatment, surface coating, plasma immersion ion implantation-deposition and laser surface structuring. Extreme ultraviolet radiations have limited penetration depth as they are readily absorbed even in low dense medium. However, their interaction with polymer surfaces is very strong due to high energy level of these photons. Therefore, EUV photons can be used to induce surface modifications in the polymer surfaces. This study is focused on the use of EUV photons for chemical surface modification of Polyethylene terephthalate (PET) films to incorporate nitrogen atoms. Nitrogen doping is often desirable in biomaterials to enhance the biocompatibility. EUV treated PET films in the presence of nitrogen and helium environments were studied using X-ray photoelectr...

In this work copper(II) L-tyrosine was firstly reported as effective precursors for laser-induced selective activation and electroless metallization of polyurethane coating. The compound in the form of powder was mixed at amount of 20 wt% with polyurethane resin to form the coating on the polycarbonate substrate. The coating was irradiated with excimer ArF laser which generated UV radiation of about 193 nm wavelength. Various laser fluences and number of laser pulses were applied to determine physicochemical changes of the coating surface layer. After irradiation coatings were electrolessly metallized. It was found that laser irradiation resulted in formation of cone-like surface geometrical structure. The high of the cones was dependent on the dose of irradiation, whereas their tops were covered with copper. The external surface layer of precipitated copper was oxidized. This, however, did not affect the possibility of the surface to be electrolessly metalized. The irradiated coatings was effectively metallized and thus deposited copper layer characterized with high adhesion strength.

Raman spectroscopy has become a standard tool for identification of hazardous materials by first responders. However, despite many advantages of this technique, it has also a limitation, which is low sensitivity. This limitation could be overcome by Surfaced Enhanced Raman Spectroscopy, technique which still waits for real-world applications. In this paper, we present an overview of both methods, Raman and SERS spectroscopies, and examples of their uses for detection and identification of biological, chemical and explosive materials.

Nanoporous anodic aluminum oxide was formed in sulfuric acid with addition of indigo carmine. During anodizing, the organic dye was incorporated into the porous oxide walls. X-ray photoelectron spectroscopy revealed the presence of nitrogen and sulfur in the anodic aluminum oxide. Two types of incorporated sulfur were found: belonging to the sulfate anions SO42 − of the electrolyte and belonging to the C-SO3− side groups of the indigo carmine. Raman spectroscopy confirmed the incorporation and showed that the inorganic–organic hybrid material inherited optical properties from the indigo carmine. Typical modes from pyrrolidone rings, unique for indigo carmine in the investigated system (650 and 1585 cm− 1), were found to be the strongest for the greatest anodizing voltages used. Despite the indigo carmine incorporation, the morphology of the oxide is still nanoporous and its geometry is still tuned by the voltage applied during aluminum anodization. This work presents an inexpensive and facile approach to doping an inorganic oxide material with organic compounds.

Extreme ultraviolet (EUV) surface modification of polytetrafluoroethylene (PTFE) was performed in order to enhance the degree of biocompatibility. Polymer samples were irradiated by different number of EUV shots using a laser–plasma based EUV source in the presence of nitrogen gas. The physical and chemical properties of EUV modified PTFE samples were studied using Atomic Force Microscopy, X-ray photoelectron spectroscopy and water contact angle (WCA) methods. Pronounced wall type micro and nano-structures appeared on the EUV treated polymer surfaces resulting in increased surface roughness and hydrophobicity. Stronger cell adhesion and good cell morphology were observed on EUV modified surfaces by in-vitro cell culture studies performed using L929 fibroblasts.

Polycaprolactone (PCL) is a biodegradable and biocompatible polyester whose low melting point facilitates production of 3D porous scaffolds with precisely defined dimensions and internal architecture by rapid prototyping techniques. To improve the suitability of such PCL scaffolds for bone regeneration applications, they were coated with inorganic layers of calcium phosphate (CaP) and CaP doped with 0.6% w/v magnesium (CaP+Mg) using pulsed laser deposition (PLD) and characterized in vitro using osteoblast-like Saos-2 cells. Saos-2 cells were able to adhere to all scaffolds. CaP+Mg coatings significantly increased activity of alkaline phosphatase (ALP), an early differentiation marker, after 7 days. However, gene expression of ALP after 7 days was markedly lower on the same scaffolds. These data show the feasibility of coating PCL with CaP layers by PLD and the possibility of influencing osteoblastic differentiation by magnesium doping of the CaP coating.

In this work experimental results are presented and analyzed for catalytic platinum films of ultra-low thickness of 0.09–3.47 nm and Pt loading of 0.18–7.44 μg cm−2 deposited using the PLD method with an ArF excimer laser (λ = 193 nm) at room temperature. For Pt deposited on the surface of the Nafion® membrane (electrolyte), in a fuel cell with PLD Pt working as oxygen cathode the peak power density is obtained equal to 59.36 mW cm−2 for the Pt loading of 1.24 μg cm−2. In the case of Pt deposition on the gas-diffusion layer (as cathode), a much higher maximum power density of 106.36 mW cm−2 at the same loading and a maximum of 188.44 mW cm−2 at the 7.44 μg cm−2 loading is observed. Experiments are also presented of Nafion® modification before the deposition of Pt on the Nafion®, in which the surface of the membranes is enlarged by bombarding with Ar ions from a plasma generator of RF 13.56 MHz. The electrochemical activity of the elements prepared by PLD is assessed in a H2/Pt/Nafion®/Pt/O2 PEMFC. The structure and morphology of the surface layers is examined by AFM and SEM microscopy.

Boron nitride coatings have been deposited onto high-speed steel substrates using pulsed laser deposition technique combined with RF-discharge. In order to improve adhesion and reduce internal stresses, substrates were subjected to gas nitriding. The structure and morphology of coatings were investigated applying atomic force microscopy (AFM) and FTIR spectroscopy. Nanohardness and elastic modulus were examined employing a nanoanalyzer (CETR). On the basis of the conducted experiments, stable, crystalline, multiphase coatings have been obtained. It has been proved that morphology, structure and mechanical properties strongly depend on the parameters of the PLD process; in particular, the temperature of the substrate has a crucial influence on the properties of BN coatings.

In this study, surface modification of fluoropolymer Polyvinyl fluoride (PVF) films was performed using Extreme Ultraviolet (EUV) radiations to induce patterned structures on surface and to provide control over the surface wettability. Specially developed laser produced plasma based EUV source was used for surface structuring. The double stream gas-puff target was produced by injection of krypton and xenon (KrXe) gas mixture into a hollow stream of helium. Commercially available EKSPLA Nd:YAG 1.06 micron laser was used to irradiate the KrXe gas puff target with 3 nanosecond pulse duration having 0.8 J energy. The PVF films were irradiated with 50 and 200 EUV pulses. The surface characterisation of the pristine and EUV modified PVF polymer films was performed by Atomic Force Microscopy (AFM) for morphological modifications. To investigate chemical modifications, X-ray Photoelectron Spectroscopy was used. The wettability of the sample surfaces was examined by Water Contact Angle (W CA) measurements. EUV surface modification of PVF films resulted in formation of wall type rippled structures on the polymer surfaces. The surface roughness of the EUV treated surfaces was increased up to 287 nm and 21° reduction was observed in the WCA of the PVF films. Successful surface structuring and wettability control was obtained using EUV surface modification of PVF films.

In this work we compare two InAs/GaSb superlattice samples grown in MBE VIGO/MUT laboratory on 2 inch (001) GaAs substrate, using MBE technique. Both samples have the same architecture, however their growth processes were conducted at different temperatures. For sample A the growth temperature was equal 668 K (395°C), for sample B 588 K (315°C). Photoluminescence measurements were performed at 30 K. For sample A there is no photoluminescence signal, while spectrum for sample B consists of two peaks: bandgap peak at 0.5 eV and deep state peak at 0.25 eV. X-ray diffraction (XRD) measurements indicate that sample A has better crystallographic quality than sample B. Raman spectra consists of low energy peaks (20-100 cm-1) which confirm the existence of superlattice for both samples [4]. Additionally, for sample A there are peaks related to Sb precipitates. It suggests that except the InAs/GaSb superlattice there is an additional Sb layer which may disturb band structure of superlattice and cause the disappearance of photoluminescence for sample A.

In this work we compare two superlattices: InAs/GaSb (sample A) and InAs/InAsSb (sample B). Both samples were grown in MBE VIGO/ MUT laboratory on 2 inch (001) GaAs substrate using MBE technique. We characterized quality and thickness of the samples using three methods: photoluminescence, X-ray diffraction (XRD) and Raman scattering. Period of superlattice layers was obtained using Raman scattering and XRD measurements. For sample A it was equal 5.3 nm and 4.76 nm for InAs and GaSb layers respectively, for sample B 8.3 nm and 9.4 nm. Photoluminescence spectrum for sample A exhibits two peaks: band gap peak at 0.5 eV and deep state peak at 0.25 eV. Spectrum for sample B consists of one band gap peak at 0.17 eV.

The use of porous titanium-based implant materials for bone contact has been gaining ground in recent years. Selective laser melting (SLM) is a rapid prototyping method by which porous implants with highly defined external dimensions and internal architecture can be produced. The coating of porous implants produced by SLM with ceramic layers based on calcium phosphate (CaP) remains relatively unexplored, as does the doping of such coatings with magnesium (Mg) to promote bone formation. In this study, Mg-doped coatings of the CaP types octacalcium phosphate and hydroxyapatite (HA) were deposited on such porous implants using the pulsed laser deposition method. The coated implants were subsequently implanted in a rabbit femoral defect model for 6 months. Uncoated implants served as a reference material. Bone-implant contact and bone volume in the region of interest were evaluated by histopathological techniques using a tri-chromatographic Masson-Goldner staining method and by microcomputed tomography (µCT) analysis of the volume of interest in the vicinity of implants. Histopathological analysis revealed that all implant types integrated directly with surrounding bone with ingrowth of newly formed bone into the pores of the implants. Biocompatibility of all implant types was demonstrated by the absence of inflammatory infiltration by mononuclear cells (lymphocytes), neutrophils, and eosinophils. No osteoclastic or foreign body reaction was observed in the vicinity of the implants. µCT analysis revealed a significant increase in bone volume for implants coated with Mg-doped HA compared to uncoated implants.

Polycarbonate Polymer Surface Modi cation by Extreme Ultraviolet (EUV) Radiation I.U. Ahada,b,∗, B. Budner, B. Korczyc, H. Fiedorowicz, A. Bartnik, J. Kostecki, S. Burdy«ska and D. Brabazon Institute of Optoelectronics, Military University of Technology, S. Kaliskiego 2, 00-908 Warszawa, Poland Advanced Processing Technology Research Centre, School of Mechanical and Manufacturing Engineering Faculty of Engineering & Computing, Dublin City University, Dublin 9, Ireland

Electrocatalysis can be enhanced either by using more active catalysts or by means of external process intensifications exploiting different energy types. The improvement of oxygen reduction reaction (ORR) efficiency by using an external magnetic field is technologically practical yet poorly scrutinized. An iron/nitrogen/sulfur-co-doped carbon gel (Fe-N-C/S) is studied as a non-precious metal catalyst for the ORR under an external magnetic field generated by a permanent magnet. The application of a magnetic field enhances the ORR process in both acidic and alkaline environments and yields higher selectivity towards 4e− electroreduction of O2. To elucidate the origin of the observed phenomena and show the role of the catalyst’s components, samples either free of sulfur (Fe-N-C) or iron (N-C/S) are studied as references. Moreover, the highly porous carbon gel constitutes an attractive substrate for enzyme immobilization. Modification of the catalyst with laccase (a multicopper oxidase enzyme) additionally strengthens the efficiency of O2 electroreduction.

The photoluminescence (PL) properties of tin oxide nanostructures are investigated. Three samples of different morphology, induced by deposition process and various geometrical features of nanoporous anodic aluminum oxide (AAO) substrate, are analyzed. X-ray photoelectronic spectroscopy (XPS) analysis reveals the presence of two forms of tin oxide on the surface of all studied samples: SnO and SnO 2 . The former form is typical for reduced surface with bridging oxygen atoms and every other row of in-plane oxygen atoms removed. The oxygen defects give rise to a strong emission in visible region. Two intense PL peaks are observed centered at about 540 (band I) and 620 (band II) nm. The origin of these bands was ascribed to the recombination of electrons from the conduction band (band I) and shallow traps levels (band II) to the surface oxygen vacancy levels. Upon deposition of Au nanoparticles on the top of tin oxide nanostructures the emission at 540 and 620 nm disappears and a new band (band III) occurs in the range >760 nm. The PL mechanism operating in the studied systems is discussed. The tin oxide/Au nanocomposites can be used as efficient multi-band light emitters in a wide (from visible to near infrared) wavelength range.

In this work the quality, arrangement, composition, and regularity of nanoporous AAO formed on the low-purity (AA1050) and high-purity aluminum during two-step anodization in a mixture of sulfuric acid solution (0.3 M), water and glycol (3:2, v/v), at various voltages (15, 20, 25, 30, 35 V) and at temperature of −1 °C, are investigated. The electrochemical conditions have allowed to obtain pores with the size ranging from 30 to 50 nm, which are much larger than those usually obtained by anodization in a pure sulfuric acid solution (