In order to optimise surface characteristics, corrosion and scratch damage, as important factors for accepting a metallic implant at conditions of a human body, commercially pure titanium (cpTi) can be modified by different treatments, including high pressure torsion (HPT) and anodic oxidation (AO). Here, a nanotube oxide layer on the surface of ultrafine-grained commercially pure titanium (UFG cpTi) is formed using AO in 1M H3PO4 + NaF solution during 60 min. SEM microphotographs show that AO with selected parameters can lead to the formation of a highly regular oxide layer with nanotubes on the surface of UFG cpTi. Determination of the surface contact angle shows that the surface of UFG cpTi after AO is more hydrophilic than before AO treatment. In order to characterise the surface topography and adhesion of formed nanotubes, scratch testing on the UFG cpTi surface after AO treatment is done. Corrosion resistance is tested in Ringer's solution with pH value of 5.5 at 37 degrees C to simulate the environment in the human body. UFG cpTi before and after AO is analysed by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarisation. The inner barrier and outer porous surface layers are highly resistant with capacitive behaviour for both tested materials, but the synergistic action of HPT and AO treatments led to improved corrosion resistance and therefore a reduced corrosion rate for commercially pure titanium in the conditions of the human body.

This paper describes severe plastic deformation (SPD) procedures, which are utilized to form an ultrafine-grained structure in metallic biomaterials. During the SPD process, a solid material sample is subjected to very high loads without a significant change in sample dimensions. In the present work, the high-pressure torsion (HPT) process, as one of the SPD techniques, which achieves a high degree of deformation and ensures refinement of the microstructure, will be discussed in more detail. Considering that grain size control is accepted as a method to obtain materials with desired characteristics, an overview of the properties of ultrafine-grained titanium-based biomaterials to be used in medicine is given. Moreover, particular attention is dedicated to the influences of HPT process parameters, primarily hydrostatic pressure, and number of revolutions during torsion, on the grain size and physical and mechanical characteristics (modulus of elasticity, microhardness, and tensile properties), corrosion resistance, and biocompatibility of the titanium-based biomaterials. A review of the literature indicates that titanium-based materials obtained by the SPD process show improved mechanical and physical properties without losing biocompatibility and corrosion resistance, which suggests that these methods of obtaining implants are something that should be further developed in the future.

The coarse-grained (CG) and ultrafine-grained (UFG) Ti-13Nb-13Zr alloys were used as tested materials in this study. The UFG alloy was obtained using a high-pressure torsion process (HPT) under a pressure of 4.1 GPa with a rotational speed of 0.2 rpm up to 5 rotations at room temperature. The structure of titanium alloy may be modified by high-pressure torsion (HPT) which is one of the most popular severe plastic deformation (SPD) methods. HPT process leads to the forming of submicron-sized grains in structure. Also, the HPT process leads to improving the mechanical and corrosion properties of titanium alloy. In order to analyze the influence of the HPT process on the morphology and characteristics of the nanostructured surface, Ti-13Nb-13Zr alloy was modified by anodic oxidation. Anodic oxidation in the 1M H3PO4 + NaF electrolyte was used as a method for the nanostructured surface of titanium-based materials. Scanning electron microscopy (SEM) was used to characterize the morphology of the surface, while surface roughness was determined using atomic force microscopy (AFM). The surface mechanical properties before and after the anodic oxidation were examined using the nanoindentation test. Corrosion resistance was tested in artificial saliva with a pH value of 5.5 at 37°C, to simulate the environment in the human body. The impact of the HPT process on the morphology of the nanostructured surface (homogeneity of the modified surface, diameter, wall thickness, and length of nanotubes) has been shown. It has been shown that anodic oxidation increases the roughness of the surface, while this increase is more pronounced after the HPT process. Characterization of the CG and UFG TNZ alloy surface after anodic oxidation showed a decrease in the values of surface mechanical properties, whereby they approached the values of the mechanical properties of human bone tissue. Also, results showed that corrosion resistance was increased after anodic oxidation, for both materials.

Different treatments of fish scales from carps (Cyprinus carpio) (FS)—mechanical milling, modified with cerium dioxide (CeO2) nanoparticles and controlled carbonization of FS and modification with CeO2—were applied to obtain FS, FS-CeO2 and CFS-CeO2 bio-adsorbents. The synthesized adsorbents were used for As(V) and Cr(VI) oxyanion separation from water. Porosity and the amount of CeO2 nanoparticles deposition were controlled using different experimental conditions. Response surface methodology (RSM) was used to select optimal parameters for adsorbent synthesis to obtain the highest adsorption capacity. The structural and surface characteristics of the synthesized adsorbents were examined using FTIR, XRD and SEM techniques. The efficiency of pollutant removal was analyzed in terms of varying experimental conditions: the mass of adsorbent, pH, temperature and contact time. RSM was also used to optimize adsorption and desorption processes. The adsorption data, obtained at 25, 35 and 45 °C, were processed using Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm and Van’t Hoff thermodynamic models. The FS-CeO2 bio-adsorbent showed good adsorption capacities of 92.61 and 65.50 mg g−1 for As(V) and Cr(VI) ion removal, respectively, obtained by using the Langmuir model. Thermodynamic parameters proved that adsorption was a viable, spontaneous and endothermic process. The results from kinetic modeling indicated that both adsorbate and surface functional group concentration determine overall kinetic law with the highest participation of intra-particle diffusion resistance to pollutant transport. Exceptional adsorption and desorption performances of FS-CeO2 in conjunction with the bio-based origin of synthesized adsorbents offer valuable alternatives for the remediation of polluted water.

Primary implant stability after implantation is associated with its good mechanical contact with the touching tissue. Adequate integration of an implant material with the bone is required to provide safety and efficiency of the implant over its life. Generally, two surface properties are the most important facts for tissue replay to the implant material: the surface morphology and chemical structure. Compared with a smooth implant surface, a controlled rough surface provides more surface area for integration with the surrounding tissues and allows successful implant ingrowth into the tissues. It was found that the nanostructured modification of the titanium surface on the level of nano-sized pores influences the adhesion, spreading, and growth of osteoblastic cells. There are many methods for nanostructure modification of biomedical alloy surfaces, but one of the common techniques is electrochemical anodization (anodic oxidation). Electrochemical anodization is a method by which a nanostructured thin film of a mixture of oxides is obtained on the material surface area. The advantage of anodic oxidation is the possibility of controlling the nanostructured morphology of the surface and dimensions of nanotubes (diameter, length, and wall thickness of nanotubes) and their shape through variation of the solution, pH value, potential, or duration of anodic oxidation. Surface modification of Ti–13Nb–13Zr alloy in the received state and the ultrafine-grained state was conducted by an anodic oxidation process in a 1 M H 3 PO 4 + NaF solution, for a period of anodizing time from 30 to 120 min. Atomic force microscopy (AFM) was utilized to characterize the topography of the modified surface, while scanning electron microscopy (SEM) was used to analyze the modified surface morphology. The results showed that a homogeneous nanotubular oxide film consisting of nanotubes could be obtained using the electrochemical anodization treatment, while the roughness of the nanostructured surface increased in comparison to the non-anodized surface. The studies given in this chapter aim to examine the morphology of the nanostructured surface and estimate in vitro biocompatibility of the abovementioned titanium alloy after the creation of the nanotubular oxide film. In vitro examinations were performed on mouse fibroblast (L929) and human fibroblast (MRC-5) cell lines. The results showed that the nanotubular oxide film obtained on the coarse-grained Ti–13Nb–13Zr (CG TNZ) and the ultrafine-grained Ti–13Nb–13Zr (UFG TNZ) increased the fractions of surviving cells compared with their counterpart alloy, while the cells had better spreading and adhesion on the nanostructured and bare surfaces of the UFG titanium alloy.

Developing highly efficient semiconductor metal oxide (SMOX) sensors capable of accurate and fast responses to environmental humidity is still a challenging task. In addition to a not so pronounced sensitivity to relative humidity change, most of the SMOXs cannot meet the criteria of real-time humidity sensing due to their long response/recovery time. The way to tackle this problem is to control adsorption/desorption processes, i.e., water-vapor molecular dynamics, over the sensor’s active layer through the powder and pore morphology design. With this in mind, a KIT-5-mediated synthesis was used to achieve mesoporous tin (IV) oxide replica (SnO2-R) with controlled pore size and ordering through template inversion and compared with a sol-gel synthesized powder (SnO2-SG). Unlike SnO2-SG, SnO2-R possessed a high specific surface area and quite an open pore structure, similar to the KIT-5, as observed by TEM, BET and SWAXS analyses. According to TEM, SnO2-R consisted of fine-grained globular particles and some percent of exaggerated, grown twinned crystals. The distinctive morphology of the SnO2-R-based sensor, with its specific pore structure and an increased number of oxygen-related defects associated with the powder preparation process and detected at the sensor surface by XPS analysis, contributed to excellent humidity sensing performances at room temperature, comprised of a low hysteresis error (3.7%), sensitivity of 406.8 kΩ/RH% and swift response/recovery speed (4 s/6 s).

Nanostructured surface modification was performed on the ultrafine-grained commercially pure titanium (UFG cpTi) using electrochemical anodization. The characterization of the morphology of the nanostructured surface obtained during different times of electrochemical anodization was done using scanning electron microscopy (SEM). The corrosion resistance of the materials was examined using the potentiodynamic method and electrochemical impedance spectroscopy (EIS), during which the electrochemical characteristics of oxide layers and the evaluation of the corrosion resistance of the mentioned materials were determined. These materials were exposed to a solution simulating conditions in the human body (artificial saliva solution) with a pH of 5.5 at a temperature of 37 ºC. The obtained results indicate the extensive influence of time, as a parameter of electrochemical anodization on the surface morphology. The electrochemical anodization of 60 minutes can lead to the creation of the nanotubular oxide layer on the UFG cpTi surface, while the electrochemical anodization of 30 and 90 minutes did not lead to the creation of the nanotubular oxide layer, but it is up to the surface modification of UFG cpTi. Electrochemical tests showed a slight increase in the corrosion resistance in a solution of artificial saliva after electrochemical anodization. Also, the electrochemical impedance spectra for anodized and non-anodized UFG cpTi show the characteristics of corrosion resistance, but the anodized UFG cpTi has better resistance to the oxide layer. It can be concluded that anodized UFG cpTi has better corrosion stability, but both non-anodized and anodized UFG cpTi show exceptional corrosion stability in simulated conditions of the human body, which makes them equally suitable for use in medicine.

In this study, we report the influence of vanadium oxide (VO), as a photosensitive component, on the photoactivity of TiO2 nanotubes (TNTs). A series of TNTs of varying tube diameter were synthesized by the anodization of titanium foils at different voltages, while vanadium oxide was deposited on TNTs by wet chemical deposition. An improvement in the optical properties of nanotubes was observed after the deposition of vanadium oxide. An improvement in the optical properties (redshift in UV-Vis spectra) of TNTs and TNT/VO was noted. The photocatalytic activity was improved with increasing tube diameter, while it was weakened after the deposition of VO. Furthermore, photoactivity was investigated in photodiodes based on TNTs or TNT/VO and single crystals of CH3NH3PbI3. The photoelectric measurement revealed that different TNT diameters did not influence the I-V characteristic of the photodiodes, while the deposition of VO improved the photocurrent for smaller TNTs.

The electro-physical properties of raw, alkali and oxidatively modified jute fabrics were investigated as complex phenomena of the interactions between the fabrics’ chemical composition, carboxyl group content, crystallinity, structural characteristics, moisture sorption, and frequency of the electric field. At 80% relative air humidity, chemically modified jute fabrics have 38–179% and 1.7–5.4 times higher dielectric loss tangent and effective relative dielectric permeability compared to unmodified. To further improve these properties, fabrics were treated with CuSO4 and Cu-based nanoparticles were in situ synthesized on their surfaces by reduction. A few smaller agglomerates of Cu-based nanoparticles were observed across the alkali modified fabric’s surface, while smaller irregularly shaped and larger agglomerates were distributed over the oxidatively modified fabric’s surface. Regardless of the type of synthesized nanostructures (metallic Cu, copper oxide (Cu2O or CuO) or their mixtures), excellent fabrics’ effective relative dielectric permeability is guaranteed. Precisely, exploitation in specific conditions that contribute to copper reduction will make jute fabrics able to store 21–163 times more energy from an external electric field than before the exploitation, which will extend their lifetime. On the other hand, with increasing the total content of Cu after the reduction and formation of agglomerates of Cu-based nanoparticles, the movements of cellulose, hemicelluloses, and lignin molecules become difficult resulting in lower energy dissipation within the chemically modified than within unmodified fabric. Applied chemical modification and coating with Cu-based nanoparticles enables designing fabrics with predictable electro-physical properties, which is very important from the application point of view.

An environmentally friendly analog of the prominent methylammonium lead halide perovskite, methylammonium bismuth bromide (MA3Bi2Br9), was prepared and investigated in the form of powder, single crystals and nanowires. Complete characterization via synchrotron X-ray diffraction data showed that the bulk crystal does not incorporate water into the structure. At the same time, water is absorbed on the surface of the crystal, and this modification leads to the changes in the resistivity of the material, thus making MA3Bi2Br9 an excellent candidate for use as a humidity sensor. The novel sensor was prepared from powder-pressed pellets with attached carbon electrodes and was characterized by being able to detect relative humidity over the full range (0.7–96% RH) at ambient temperature. Compared to commercial and literature values, the response and recovery times are very fast (down to 1.5 s/1.5 s).

Hydrogen peroxide represents an ecologically and economically acceptable agent for bleaching of flax fibers. The influence of hydrogen peroxide treatment under different conditions, i.e. hydrogen peroxide concentrations (1%, 2% and 4% w/v) and treatment temperature (50 °C, 80 °C and boiling temperature), on the chemical composition, electrokinetic and sorption properties and whiteness index of flax fibers, has been studied. The surface properties and water uptake behavior, i.e. swelling of untreated and treated flax fibers, were monitored through zeta potential measurements using the streaming potential method.The present research has found out that hydrogen peroxide simultaneously removes hemicelluloses and lignin from flax fibers. The ratio between the removal of hemicelluloses (hydrophilic component) and lignin (hydrophobic component), as well as changes in crystallinity, pore structure and carbonyl and carboxyl groups content, have a dominant effect on the electrokinetic, i.e. zeta potential versus pH and isoelectric point and sorption properties of the treated flax fiber. An increase of approximately three-to-four-fold in the whiteness index of the treated flax fibers has been observed. The established correlations between the modification conditions and properties of flax fibers, allow the utilization of hydrogen peroxide for bleaching and simultaneous fiber modification with the possibility of tailoringflax fibers properties.

X-ray photon detection is important for a wide range of applications. The highest demand, however, comes from medical imaging, which requires cost-effective, high-resolution detectors operating at low-photon flux, therefore stimulating the search for novel materials and new approaches. Recently, hybrid halide perovskite CH3NH3PbI3 (MAPbI3) has attracted considerable attention due to its advantageous optoelectronic properties and low fabrication costs. The presence of heavy atoms, providing a high scattering cross-section for photons, makes this material a perfect candidate for X-ray detection. Despite the already-successful demonstrations of efficiency in detection, its integration into standard microelectronics fabrication processes is still pending. Here, we demonstrate a promising method for building X-ray detector units by 3D aerosol jet printing with a record sensitivity of 2.2 × 108 μC Gyair-1 cm-2 when detecting 8 keV photons at dose rates below 1 μGy/s (detection limit 0.12 μGy/s), a 4-fold improvement on the best-in-class devices. An introduction of MAPbI3-based detection into medical imaging would significantly reduce health hazards related to the strongly ionizing X-rays' photons.

Severe plastic deformation (SPD) is a popular group of techniques applied to achieve the nanostructuring of the metallic biomaterials and improvement of their mechanical characteristics. One of the most commonly used SPD methods is the high-pressure torsion (HPT) technique which enables the obtainment of the microstructure with small grains and high strength. In the present study, the influence of the plastic deformation and surface modification treatment on the tensile and corrosion properties of the Ti–13Nb–13Zr (wt%) alloy is investigated. In that purpose, the coarse-grained (CG) Ti–13Nb–13Zr (TNZ) alloy was subjected to the HPT processing by applying a pressure of 4.1 GPa with a rotational speed of 0.2 rpm and 5 revolutions at room temperature to obtain the ultrafine-grained (UFG) microstructure. The alloy microstructure before and after HPT processing was analysed using the scanning electron microscopy (SEM) and the X-ray diffraction (XRD). The homogeneity of the UFG TNZ alloy was determined by microhardness testing and microscopic observations. The nanotubular oxide layer on the surface of the TNZ alloy, both in CG and UFG condition, was formed by electrochemical anodization in 1 M H3PO4 + NaF electrolyte for 90 min. SEM analysis was used to characterise the morphology of the anodized surfaces, while energy dispersive spectroscopy was applied to determine the chemical composition of the nanostructured layers formed at the alloy surfaces. Mechanical properties of the TNZ alloy, before and after HPT processing and electrochemical anodization, were determined by tensile testing. After tensile testing, the fractographic analysis was conducted to identify the fracture mechanisms. The potentiodynamic polarization technique was used to determine the corrosion resistance of the alloy before and after plastic deformation and surface modification treatment. The obtained results showed that the alloy is reasonably homogeneous after the HPT processing. The XRD analyses reviled the presence of α′ and β phases in the CG TNZ alloy microstructure, while the additional ω phase was detected in the microstructure of the UFG TNZ alloy. The HPT obtained alloy exhibits higher hardness and improved tensile properties than the alloy in the as-received CG condition, while the electrochemical anodization leads to a decrease of its mechanical properties. Both CG and UFG alloys show excellent corrosion stability in Ringer’s solution. Moreover, electrochemical anodization leads to a decrease or an increase of the corrosion resistance of these materials, depending on the morphology of the formed nanotubular surface layers. The results indicate that the anodized CG TNZ alloy is characterized by a lower modulus of elasticity and better corrosion resistance properties than the anodized UFG TNZ alloy.

The controllable synthesis of rutile TiO2 single crystal particles with the preferential orientation of {111} facets still remains a scientific and technological challenge. Here, we developed a facile route for fabrication of rutile TiO2 nanorod crystals (RTiO(2)NRs) having high ratios of oxidative {111} to reductive {110} surfaces. RTiO(2)NRs were synthesized using a peroxo-titanium complex (PTC) approach, which was controlled by changing the Ti/H2O2 ratio. The thus obtained RTiO(2)NRs revealed a high tendency to agglomerate through orientation-dependent attachment along the {110} facets. This resulted in an increased {111}/{110} surface ratio and led to a markedly improved photocatalytic activity of RTiO2NR aggregates. The reported findings illustrate the rich potential of the herein proposed facile and energy-efficient synthesis of nanostructured rutile TiO2-based photocatalysts.

Due to their excellent mechanical properties and corrosion resistance, titanium-based materials are widely represented in aeronautics, chemical industry and medicine, where they are considered the best replacement for damaged hard tissues. In order to obtain optimal properties for medical applications, commercially pure titanium (cpTi) is often alloyed. The β-type titanium alloys containing Nb, Zr, Ta, Mo, Sn have attracted considerable attention, due to their unique combinations of high strength, low modulus of elasticity, superior corrosion resistance and biocompatibility. Also, titanium-based materials can be processed by surface modifications, including the anodization, which belongs to the group of chemical nanostructured surface modifications. Analysis of microstructure of two-phase Ti-13Nb-13Zr (TNZ) alloy was done by Scanning Electron Microscopy (SEM). Characterisation of surface, obtained by anodization in the H3PO4 + NaF solution, during 90 minutes process, was performed by SEM. Micro Tensile Specimens (MTS) were cut from TNZ and anodized TNZ disks and were subjected to the tensile test using servo-hydraulic testing machine Instron 1255. Stereometric measurement of strain at the surface of the MTS during tension was done using the Aramis system. Results showed that anodization process led to a creation of heterogeneous layer of nanotubes. Anodized TNZ alloy had lower elastic modulus and tensile strength comparing to the initial alloy. In order to better understand tensile behaviour, numerical analysis of non-anodized alloy was done. The 3D numerical model of MTS, which simulated the tensile test, was made in Abaqus software package. Good correlation between experimental and numerical results was obtained.

Potential non-toxic pink and red ceramic pigments based on CeO2 were successfully synthesized by selfpropagating room temperaturemethod and thermally treated at 600, 900 and 1200?C for 15min. The structure, morphology and optical properties, as well as thermal stability of Ce1-xErxO2-? and Ce1-xPrxO2-?(x = 0.05) were examined. Single-phase composition of all obtained CeO2 pigments was confirmed using XRPD method and Raman spectroscopy and it was not dependent on temperature. The mechanism of structural behaviour was thoroughly examined using Raman and FTIR spectroscopy. Nanometric dimensions of the crystallites of all pigments were confirmed using XRPD, TEM and FE-SEM analysis. Colour properties were dependent on the temperature treatment, and their position in the chromaticity diagram was studied using UV/VIS spectrophotometry. Colour efficiency measurements were supplemented by colorimetric analysis. It is proved that all samples are thermally stable in the investigated temperature range (up to 1200?C), and their potential application as environmentally friendly pigments of desired colour is confirmed.

Two-step synthesis of Fe2O3 particles, performed by precipitation from iron(III) chloride (FeCl3?6H2O) using ammonium hydroxide in first step and calcination at 400 and 700?C during 4 h, provided Fe2O3 400?C and Fe2O3 700?C photocatalysts, respectively. The electrospinning process was used to prepare iron oxide fibers, named Fe2O3 fiber. Morphological and structural properties of samples were determined by Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), Fourier Transform Infra-Red (FT-IR) and BET/BJH analysis. It was found that the ?-Fe2O3 phase (hematite) has shown the compaction of the structure at 700?C, i.e. lower textural properties. Hematite particles and fibers are used for bisphenol A (BPA) removal by photocatalytic decomposition and the enhanced catalytic performance was found with the use of Fe2O3 400?C particles.

A facile synthesis was employed for three polyhedral oligo silsequioxanes (POSS), obtaining incompletely condensed structures with fern-like and cubic morphologies. Proton nuclear magnetic resonance spectroscopy (H-1 NMR) indicated the successful synthesis of the proposed POSS structures. The hydroxyl groups affected the manner and type of POSS morphology, as seen under a scanning electron microscope (SEM) and a transmission electron microscope (TEM). Fourier-transform infrared spectroscopy (FTIR) showed the availability of surface hydroxyl groups that contributed to the formation of a higher amount of char residue, as found from TGA analysis. The highest decomposition temperature (281 degrees C) and the least char residue were found for a cross-linkable POSS, obtained by esterification of the hydroxyl groups with methacryloyl chloride. (C) 2019 Elsevier Ltd. All rights reserved.

Synthesis of branched aminated waste polyacrylonitrile (PAN) fibers, realized in a three addition/ amidation successive steps, was performed in order to obtain AS3-PAN adsorbent.Influence of various operating parameters such as pH, contact time, adsorbent mass and initial concentration of pollutants, on adsorption capacity has been studied.Design of the experimental plan of adsorption experiments, defined by response surface methodology (RSM), rationalized the number of necessary experiments.The calculated adsorption capacities for AS3-PAN, obtained by Langmuir model, were 58.94, 41.07, 34.51, 24.54 and 29.61 mg g -1 for Pb 2+ , Cd 2+ , Ni 2+ , Cr(VI) and As(V) ion, respectively.The results of pseudo-second-order reaction rate and Weber-Morris kinetic model indicated significant resistance due to intra-particle (pore) diffusion.The experimental results were compared with the theoretically calculated ones, obtained by RSM prediction model, and validation of applied methodology was performed by testing the quality of the regression analysis with analysis of variance test.

On the surface of the ultrafine-grained Ti-13Nb-13Zr alloy and the coarse-grained Ti-13Nb-13Zr alloy nanotubular oxide layers were formed by electrochemical anodization in the 1 M H3PO4 + NaF electrolyte in order to evaluate the electrochemical behaviour in the artificial saliva. SEM images showed that homogeneous nanotubular oxide layers could be formed by anodic oxidation of titanium alloys in an electrolyte with fluoride ions. These two titanium alloys, like other materials developed to replace the bone tissue in the human body, have to be highly corrosion resistant, which is one of the most common requirement in terms of the biocompatibility, damage and fracture prevention. The alloys were analysed by means of the electrochemical impedance spectroscopy and potentiodynamic polarization. The analyzed alloys had good corrosion stability, while nanotubular oxide layer improved their corrosion resistance.