The microbiocidal properties of zinc, in both elemental and oxide forms, are well established. In this study, nanometric ZnO layers with a thickness of 40-150 nm were deposited on glass substrates using the sol-gel dip-coating method. The coatings were prepared by 3 or 6 dipping cycles, followed by a thermal treatment at 773 K for 1 h. Two thermal treatment schemes were applied: annealing after each immersion (x) and single annealing after all immersions (x & lowast;). Structural and morphological characterization showed, that the sequence of annealing strongly influenced a zinc oxide crystallite size: 18-28 nm for the coatings annealed after each immersion and 10-13 nm for the coatings annealed once. The spectroscopic ellipsometry confirmed uniformity of the films and revealed that a bacterial biofilm thickness on uncoated glass reached 100-120 nm, while the presence of ZnO layers significantly reduced this to 70-80 nm for Escherichia coli and 20-40 nm for Staphylococcus aureus, independently of the preparation route. Antibacterial testing demonstrated that the coatings annealed after each immersion (3x, 6x) achieved higher reduction of E. coli (13 % for 3x and 60 % for 6x respectively), whereas the coatings annealed once (3x & lowast;, 6x & lowast;) were more effective against S. aureus, with the strongest effect observed for 6x & lowast; (99 % bacteria reduction). Ion-release studies indicated, that in a hydrated environment, the coatings subjected to the single-step annealing released more Zn2+ ions (3.25-4.25 ppm) compared to the multi-step annealed films (<4.25 ppm after 24 h incubation), which correlated with their higher antibacterial activity against S. aureus. Qualitative observations further confirmed, that the presence of crystallites of varying size affects roughness and wettability, which, together with ion release and ROS generation, governs the bactericidal response. Importantly, all ZnO coatings reduced the biofilm formation while maintaining high optical transparency (90 % transmittance), highlighting their potential for applications in touchscreens, packaging, and photovoltaic devices.

The study is focused on the technology for surface modification of AZ31 magnesium alloy for biomedical applications, in particular in implantology. The experimental procedure consists of intentional stages that involve chemical treatment in piranha solution, plasma chemical activation of the alloy surface using Ar and O2 as gaseous precursors, and biopolymer coatings deposition—based on polylactic acid (PLA) and poly(lactic-co-glycolic acid) (PLGA) with the addition of caffeic acid—utilizing the immersion method. In the course of the experiment, the validity of the investigated technology of surface modification of AZ31 magnesium alloy was confirmed. The pre-treatment step guaranteed obtaining a higher surface roughness, resulting in homogeneous and stable biopolymer coatings with proper adhesion to the substrate. Moreover, the corrosion studies conducted confirmed better corrosion behaviour of the modified samples in SBF corrosive medium, and no significant release of the alloy-related ions was observed. Furthermore, the biopolymer coatings ensured non-cytotoxicity towards the MG-63 cell line and promoted cell proliferation with proper morphology. Based on the obtained results, it may be concluded that the proposed technology can be treated as an interesting and promising surface-engineering strategy for implantology and biodegradable materials applications.

The study examined the possibility of intercalation of montmorillonite with neomycin in an aqueous drug solution and the factors influencing the effectiveness of this process, such as the ion exchange capacity and process conditions, including the time and temperature of incubation with the drug. X-ray diffractometry (XRD), infrared spectroscopy (FTIR), thermal analysis (DSC/TG), and Zeta potential measurement were used to confirm drug intercalation as well as to investigate the nature of clay–drug interactions. The obtained conjugates with the most favorable physicochemical properties were also tested for antibacterial response against Gram-negative bacteria (Escherichia coli) to confirm that the bactericidal properties of neomycin were retained after intercalation and UV–VIS spectrophotometry was used to examine the kinetics of drug release from the carrier. The results of the conducted research clearly indicate the successful intercalation of neomycin in montmorillonite and indicate the influence of process parameters on the properties of not only the conjugates themselves but also the properties of the intercalated drug, particularly its bactericidal activity. Ultimately, a temperature of 50 °C was found to be optimal for effective drug intercalation and the conjugates obtained within 2 h showed the highest antibacterial activity, indicating the highest potential of the thus-obtained montmorillonite conjugates as neomycin carriers.

The aim of the work was to examine the possibility of using modified halloysite nanotubes as a gentamicin carrier and to determine the usefulness of the modification in terms of the effect on the amount of the drug attached, its release time, but also on the biocidal properties of the carriers. In order to fully examine the halloysite in terms of the possibility of gentamicin incorporating, a number of modifications of the native halloysite were carried out prior to gentamicin intercalation with the use of sodium alkali, sulfuric and phosphoric acids, curcumin and the process of delamination of nanotubes (expanded halloysite) with ammonium persulfate in sulfuric acid. Gentamicin was added to unmodified and modified halloysite in an amount corresponding to the cation exchange capacity of pure halloysite from the Polish Dunino deposit, which was the reference sample for all modified carriers. The obtained materials were tested to determine the effect of surface modification and their interaction with the introduced antibiotic on the biological activity of the carrier, kinetics of drug release, as well as on the antibacterial activity against Escherichia coli Gram-negative bacteria (reference strain). For all materials, structural changes were examined using infrared spectroscopy (FTIR) and X-ray diffraction (XRD); thermal differential scanning calorimetry with thermogravimetric analysis (DSC/TG) was performed as well. The samples were also observed for morphological changes after modification and drug activation by transmission electron microscopy (TEM). The conducted tests clearly show that all samples of halloysite intercalated with gentamicin showed high antibacterial activity, with the highest antibacterial activity for the sample modified with sodium hydroxide and intercalated with the drug. It was found that the type of halloysite surface modification has a significant effect on the amount of gentamicin intercalated and then released into the surrounding environment but does not significantly affect its ability to further influence drug release over time. The highest amount of drug released among all intercalated samples was recorded for halloysite modified with ammonium persulfate (real loading efficiency above 11%), for which high antibacterial activity was found after surface modification, before drug intercalation. It is also worth noting that intrinsic antibacterial activity was found for non-drug-intercalated materials after surface functionalization with phosphoric acid (V) and ammonium persulfate in the presence of sulfuric acid (V).

The main objective of the work was to create a layer of carbon nanofibre on the surface of the NiTi shape memory alloy. The coating process was carried out in three stages. First, polyacrylonitrile was deposited by electrospinning. Then it was stabilized at temperatures up to 250 degrees C. The last stage was the carbonization performed below 1000 degrees C. The microstructure of the obtained coatings was observed using a scanning electron microscope. The X-ray diffraction techniques were applied to analyze the coating structure. After the polyacrylonitrile deposition, the fibers had an average diameter of about 280 nm, and the final fibers were almost twice as tiny. The applied steps also changed the phase and crystalline state of the fibers, finally leading to the formation of amorphous-nanocrystalline graphite.

In this paper, we investigated the optical and thermo-optical properties of a-SiNx:H layers obtained using the PECVD technique. SiNx:H layers with different refractive indices were obtained from silane and ammonia as precursor gases. Surface morphology and chemical composition studies were investigated using atomic force microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy and energy dispersive spectrometry methods. Spectroscopic ellipsometry was used to determine the optical indexes, thicknesses and optical bandgap of the films. The main purpose was to identify the thermo-optical characteristics of layers with different refractive indexes. Thermo-optical studies were performed to determine the temperature hysteresis of optical parameters. These measurements showed that after annealing up to 300 °C and subsequent cooling, the value of optical parameters returned to the initial values.

The results of plasmochemical modification on Crofer 22APU ferritic stainless steel with a SiCxNy:H layer, as well as the impact of these processes on the increase in usability of the steel as intermediate-temperature solid oxide fuel cell (IT-SOFC), interconnects, are presented in this work. The layer was obtained using Radio-Frequency Plasma-Activated Chemical Vapor Deposition (RF PA CVD, 13.56 MHz) with or without the N+ ion modification process of the steel surface. To determine the impact of the surface modification on the steel's resistance to high-temperature corrosion and on its mechanical properties, the chemical composition, atomic structure, and microstructure were investigated by means of IR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Microhardness, Young's modulus, wear rate, as well as electrical resistance, were also determined. Micromechanical experiments showed that the plasmochemical modification has a positive influence on the surface hardness and Young's modulus of the investigated samples. High-temperature oxidation studies performed for the samples indicate that N+ ion modification prior to the deposition of the SiCxNy:H layer improves the corrosion resistance of Crofer 22APU steel modified via CVD. The area-specific resistance of the studied samples was 0.01 Ω·cm2, which is lower than that of bare steel after 500 h of oxidation at 1073 K. It was demonstrated that the deposition of the SiCxNy:H layer preceded by N+ ion modification yields the best properties.

The main problem of organic light-emitting diodes (OLEDs) is their degradation caused by the interaction of the polymer with atmospheric factors. The development of new encapsulation methods and materials for OLEDs can solve this problem. In this work prompted us to investigate the possibility of using hydrogenated amorphous carbon nitrogen-modified (a-C:N:H) layer as protective passive coatings. The layers were deposited on the active polymer layer and as a stand-alone active layer in the devices by radio frequency plasma assisted chemical vapor deposition (13.56 MHz). Different types of the diodes architectures (glass/ITO/PVK/Ca/Al, diodes with glass/ITO/PVK/a-C:N:H/Ca/Al and glass/ITO/a-C:N:H/Ca/Al) were prepared for which specified of the current-voltage and electroluminescent-voltage characteristics. The layers structure and morphology were assessed by X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX). The UV Vis spectroscopy studies have been carried out for the a-C:N:H layer and absorption bands were determined. The photoluminescence and fluorescence of the layers were confirmed. The optical properties and chemical stability were measured by spectroscopic ellipsometry. The influence of solvents on the dispersion dependence of the refractive index and extinction coefficient was also determined. The obtained results are promising in the context of the layers applications in OLEDs technology.

Controlling environmental pollution is a burning problem for all countries more than ever. Currently, due to the increasing industrialization, the number of days when the limits of air pollutants are over the threshold levels exceeds 80–85% of the year. Therefore, cheap and effective sensors are always welcome. One idea is to combine such solutions with cars and provide real-time information about the current pollution level. However, the environmental conditions are demanding, and thus the developed sensors need to be characterized by the high 3S parameters: sensitivity, stability and selectivity. In this paper, we present the results on the heterostructure of CuO/SnOx and SnOx/CuO as a possible approach for selective NO2 detection. The developed gas sensors exhibited lower operating temperature and high response in the wide range of NO2 and in a wide range of relative humidity changes. Material characterizations and impedance spectroscopy measurements were also conducted to analyze the chemical and electrical behavior.

Optical and thermo-optical studies of hydrogenated amorphous silicon-rich nitride films were carried out. The films were produced by plasma-assisted chemical vapor deposition on glass. It is shown that the films deposited under appropriately selected processing conditions contain little nitrogen, as confirmed by Fourier-transform infrared spectroscopy therefore they are referred to as silicon-rich nitrides, a-SRN:H. Spectroscopic ellipsometry, reflectance, and transmittance spectroscopy were used to determine the optical indexes of the films and their thicknesses. It results from the ellipsometric measurements performed within a 190-1700nm spectral wavelength range that a-SRN:H films exhibit a high refractive index of about 3.7. It is also shown that post-deposition annealing up to 300°C does not affect the optical parameters of the films. Additionally, they are transparent in the near-infrared region, which makes them a good candidate for applications in various optoelectronic systems.

In this work, the investigation results of amorphous hydrogenated silicon nitride layers (a-SiNx:H) obtained by plasma-enhanced chemical vapour deposition technology have been presented. Chemical compositions, surface morphology and surface topography studies were performed on the layers using Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectrometry and atomic force microscopy methods. By using optical methods: spectroscopic ellipsometry and thermal spectroscopic ellipsometry; the optical parameters (refractive index, extinction coefficients), optical band gap of a-SiNx:H layers and film thickness in the spectral range of 190-1700 nm have been determined. Additionally, we carried out thermo-optical studies to determine the temperature hysteresis of optical parameters. a-SiNx:H layers exhibit similar properties as non-stoichiometric Si-rich silicon nitride layers. They exhibited amorphous structure and their main components were silicon. After heating and cooling processes values of refractive index n and extinction coefficient k return to the baseline. In our paper we present thermal dependence of a-SiNx:H films refractive index. Presented layers showed similar optical constants to silicon substrate but they exhibiting much better dielectric properties than Si. a-SiNx:H layers exhibited very high refractive indices (about 3.8). The layers, presented in this work may potentially have broad applications in optoelectronics, photovoltaics and photonics.

Two carbon layers: micro-formed of pyrolytic carbon (CVD) and nano-constructed of multi-walled carbon nanotubes (MWCNTs) by electrophoretic deposition (EPD), both formed on a Ti support, were contacted with selected proteins. As target proteins, albumin from chicken egg white (Alb), bovine serum albumin (BSA) and human serum albumin (HSA), were tested. To unravel the carbon layer-albumin interaction 2D correlation Raman microspectroscopy was applied, checking also the importance of its origin, animal or human. 2D correlation confirms that albumin adheres to the surface of both studied carbon layers. Additionally, it allowed to resolve additional valuable characteristic, which is not directly visible in the Raman spectra. For C (CVD) carbon layer a change in albumin conformation was observed, but for nano-MWCNTs layer interactions with particular amino acid side chains with the surface was seen. Differences between albumins can drive on the synthetic material-albumin interactions.

In this work we presented the correlation between the chemical composition of amorphous Si:C:N:H layers of various content of silicon, carbon and nitrogen, and their band gap. The series of amorphous Si:C:N:H layers were obtained by plasma assisted chemical vapour deposition method in which plasma was generated by RF (13.56 MHz, 300W) and MW (2.45 GHz, 2 kW) onto monocrystalline silicon Si(001) and borosilicate glass. Structural studies were based on FTIR transmission spectrum registered within wavenumbers 400-4000 cm(-1). The presence of Si-C, Si-N, C-N, C=N, C=C, C equivalent to N, Si-H and C-H bonds was shown. The values band gap of the layers have been determined from spectrophotometric and ellipsometric measurements. The respective values are contained in the range between 1.64 eV - characteristic for typical semiconductor and 4.21 eV - for good dielectric, depending on the chemical composition and atomic structure of the layers. (C) 2016 Elsevier B.V. All rights reserved.

In this work, we investigate the optical properties and passivation effects of silicon nitride stacks deposited by the plasma enhanced chemical vapor deposition (PECVD) system. A stack of three SiNx:H layers with different refractive indices were deposited at 310 °C using silane (SiH4) and ammonia (NH3) as precursor gases. The chemical composition of the films was modulated by varying the gas flow ratio r = [NH3]/[SiH4]. Details of the optical optimization procedure are presented. Thanks to spectrophotometric and spectroscopic ellipsometry measurements we confirmed the suitability of a three layered SiNx:H stack for antireflective coating. Passivation effects were evaluated by measurements of effective carrier lifetimes. Simulated short‐circuit currents were also calculated for two fixed internal quantum efficiency IQE spectra. It was found that a triple‐layered silicon nitride coating provides lower optical reflection and better passivation for silicon p‐type than those of a single‐layered silicon nitride coating.

Purpose In this paper, we aim to investigate the influence of the hydrogenated silicon nitride layers deposited by a large area 13.56 MHz plasma-enhanced chemical vapour deposition system on the electrical activity of the surface and interfaces of the grains for solar cells fabricated on microcrystalline silicon and multicrystalline silicon. Design/methodology/approach The characterization of current-voltage parameters of 25 cm2 solar cells manufactured with different passivation and antireflective layers are presented. After spectral response measurements, external quantum efficiency was calculated, and the final results are shown graphically. The passivation effect concerning grain areas was evaluated more precisely by light-beam-induced current scan maps (LBIC). Findings The final impact of the type of passivation layer on surface and grain boundary photoconvertion in solar cells is determined. Originality/value The passivation effect concerning grain areas was evaluated more precisely by LBIC.

Amorphous a-SiCxNy:H thin films may be an alternative to a-Si:N:H coatings which are commonly used in silicon solar cells. This material was obtained by PECVD (13.56 MHz) method. The reaction gases used: silane, methane, nitrogen and ammonia. The structure of the layers were investigated by scanning electron microscopy (SEM) and infrared spectroscopy (FTIR). IR absorption spectra of a-SiCxNy:H layers confirmed the presence of various hydrogen bonds – it is important for passivation of Si structural defects. The ellipsometric measurements were implemented to determine the thickness of layers d, refractive index n, extinction coefficient k and energy gap Eg. The values of the energy gap of a-SiCxNy:H layers are in the range from 1.89 to 4.34 eV. The correlation between energy gap of materials and refractive index was found. Generally the introduction of N and/or C into the amorphous silicon network rapidly increases the Eg values.

Plasma Assisted Chemical Vapour Deposition (PA CVD) method allows to deposit of homogeneous, well-adhesive coatings at lower temperature on different substrates. Plasmochemical treatment significantly impacts on physicochemical parameters of modified surfaces. In this study we present the overview of the possibilities of plasma processes for the deposition of diamond-like carbon coatings doped Si and/or N atoms on the Ti Grade2, aluminum-zinc alloy and polyetherketone substrate. Depending on the type of modified substrate had improved the corrosion properties including biocompatibility of titanium surface, increase of surface hardness with deposition of good adhesion and fine-grained coatings (in the case of Al-Zn alloy) and improving of the wear resistance (in the case of PEEK substrate).

The paper presents the modification of the surface of the Crofer 22APU ferritic stainless steel with SiCxNy(H) layer, and its influence on the applicability of the steel in intermediate-temperature solid oxide fuel cell (IT-SOFC) interconnects. The layer was obtained via plasma-assisted chemical vapor deposition (PACVD) with and without prior nitriding. To determine the impact of the surface modification on the steel's resistance to high-temperature corrosion and the on its mechanical properties, the chemical composition, structure, and microstructure were investigated by means of FTIR, XRD, and SEM-EDS. Microhardness and Young's modulus were also measured. It was demonstrated that the deposition of the SiCxNy(H) layer in plasmo-chemical conditions after prior nitriding of the surface of the Crofer 22APU is beneficial.