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Titanium (Ti) is widely used in medical and dental implants. Calcium phosphate (CPs) coatings enhance Ti implants’ osteoinductive properties, and additives further improve these coatings. Recently, a nano amorphous calcium phosphate (nACP) coating decorated with chitosan oligolactate (ChOL) and selenium (Se) showed immunomodulatory effects. This study investigates the surface morphology, composition, bioactivity, mechanical properties, and Se-release mechanism of the nACP@ChOL-Se hybrid coating on Ti substrates. Amorphous calcium phosphate (ACP) was synthesized, and the nACP@ChOL-Se hybrid coating was deposited on Ti substrates using in situ anaphoretic deposition. Physico-chemical characterization was used to analyze the surface of the coating (scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy). The distribution of Se within the coating was examined with energy-dispersive X-ray spectroscopy (EDS). Bioactivity was evaluated in simulated body fluid (SBF), and adhesion was tested using a scratch test method. In vitro testing determined the release mechanism of Se. SEM images illustrated the surface morphology, while AFM provided a detailed analysis of surface roughness. XRD analysis revealed structural and phase composition, and EDS confirmed Se distribution within the coating. The coating exhibited bioactivity in SBF and showed good adhesion according to the scratch test. In vitro testing uncovered the release mechanism of Se from the coating. This study successfully characterized the surface morphology, composition, bioactivity, and Se-release mechanism of the nACP@ChOL-Se hybrid coating on Ti substrates, offering insights for developing immunomodulatory coatings for medical and dental applications.

Titanium and its alloys are widely used in medical devices, orthopedic implants, dental implants, and device components of aerospace industries. It is attractive for having superior room and elevated temperature mechanical properties, corrosion resistance, fatigue resistance and low weight. However, titanium and its alloys are not fully applicable replacement in biomedical application. Suitable surface modification of titanium is needed in order to obtain Ti with improved properties. This paper deals with the optimization of the in-situ anodizing/anaphoretic electrodeposition process of hydrothermally synthesized hydroxyapatite (HAp) on Ti substrate for subsequent obtaining of HAp/TiO2 composite coatings without multi-stage pre-treatment and post-treatment of titanium and oxidized titanium surface. Coatings were prepared at constant voltage of 60 V and deposition time of 1 min. The morphology of coatings was investigated using optical microscope and field emission scanning electron microscope. Fourier transform infrared spectroscopy measurements were also performed. The coating with optimal properties was obtained by deposition from suspension containing 1.0 M NaOH.

The main objective of this research was a systematic development of advanced micro/nanostructured materials based on the most used metal-oxides for ORR and metal-oxides with an extremely low-loading of Pt for comparison. Hybrid composites compared were: MnO2, La2O3, mixed lanthanum manganese oxides (LMO), and mixed lanthanum manganese oxides with reduced platinum load (LMO-Pt). The influence of the reduced amount of noble metal, as well as single oxide activity toward ORR, was analyzed. The complete electrochemical performance of the hybrid materials has been performed by means of CV, LSV, and EIS. It was shown that all synthesized catalytic materials were ORR-active with noticeable reduction currents in O2 saturated 0.1 M KOH. The ORR behavior indicated that the La2O3 electrode has a different mechanism than the other tested electrode materials (MnO2, LMO, and LMO-Pt). The EIS results have revealed that the ORR reaction is of a mixed character, being electrochemically and diffusion controlled. Even more, diffusion is of mixed character due to transport of O2 molecules and the chemical reaction of oxygen reduction. O2 diffusion was shown to be the dominant process for MnO2, LMO, and LMO-Pt electrolytic materials, while chemical reaction is the dominant process for La2O3 electrolytic materials.

This paper deals with the deposition of calcium phosphate and hybrid coatings based on calcium phosphate ceramics on titanium with improved properties by in situ anodization/anaphoretic deposition process. Hybrid coatings consisted of chitosan oligolactate (ChOL) and ChOL with Se as immunomodulatory oligoelement. The paper contributes to solving the problem of multi-stage pre-treatment and post-treatment of titanium and oxidized titanium surface to obtain a coating on the substrate, adhesion of the coating, antimicrobial and cytotoxic properties that occur in biomaterials, as well as reduced immune inflammatory response of the organism. The in situ method results in improved adhesion bioactive coating, increased bioactivity and biocompatibility with increased antimicrobial properties and absence of cytotoxicity. The studied biomaterials have improved properties such as: corrosion resistance, absence of toxicity to the human body and adequate strength, which enables their potential use in medicine and dentistry. The innovation is reflected in combining calcium phosphate coating synthesis and surface modification by partially incorporating a ceramic coating into the crystalline structure of the substrate. The characterization of the coatings obtained in this manner was performed by various physico-chemical, biochemical and biological methods. These characterization techniques included: FE-SEM, XRD, FTIR, cytotoxicity and in vivo testing.

This paper deals with the issue of defining a new method of anodizing/anaphoretic deposition for the application of calcium phosphate and hybrid coatings based on calcium phosphate ceramics on titanium and anodized titanium coatings with improved properties. Hybrid coatings consisted of chitosan oligolactate (ChOL) and ChOL with Se as immunomodulatory oligoelement. The paper contributes to solving the problem of multi-stage pre-treatment and posttreatment of titanium and oxidized titanium surface to obtain a coating on the substrate, adhesion of the coating, antimicrobial and cytotoxic properties that occur in biomaterials, as well as reduced immune inflammatory response of the organism. It primarily deals with the creation and optimization of a new in situ anodizing/anaphoretic deposition process for obtaining multifunctional composite biomaterials. The in situ method results in improved adhesion bioactive coating, increased bioactivity and biocompatibility with increased antimicrobial properties and absence of cytotoxicity. The studied biomaterials have improved properties such as: corrosion resistance, absence of toxicity to the human body and adequate strength, which enables their potential use in medicine and dentistry. The aim of the research was to define new in situ anodizing/anaphoretic deposition process and adequate modification of process parameters for application of composite calcium phosphate coatings on titanium and its alloys, wherein innovation is reflected in combining calcium phosphate coating synthesis and surface modification by partially incorporating a ceramic coating into the crystalline structure of the substrate. The characterization of the coatings obtained in this manner was performed by various physico-chemical, biochemical and biological methods. These characterization techniques included: AFM, SEM, FE-SEM, roughness testing, XRD, FTIR, bioactivity, biocompatibility, cytotoxicity, antimicrobial activity and in vivo testing.

The aim of this study was to investigate environmentally-friendly corrosion inhibitors based on the cerium-cysteine and their effect on 7xxx series aluminum alloy. The cysteine and cerium-cysteine complex structures were analyzed by Fourier-Transform Infrared spectroscopy (FTIR). The structure of cerium-cysteine was additionally determined using Nuclear Magnetic Resonance (NMR) and Elemental Analysis. Inhibitors efficiency was analyzed with Electrochemical Impedance Spectroscopy (EIS) and Potentiodynamic polarization techniques in 0.1M NaCl at room temperature, while Scanning Electron Microscopy analyzed the surface appearance and microstructure of the tested aluminum alloy with Energy Dispersive Spectroscopy (SEM / EDS) and Optical Microscope (OM). Different amounts of cysteine were examined in order to find an optimal concentration of inhibitor. The adsorption of the inhibitors followed the Langmuir isotherm, and based on the EIS results and calculated thermodynamic potential (Gibbs free energy), cysteine and cerium-cysteine proved to be good inhibitors for tested aluminum alloy. The optimal cysteine concentration of 0.06 mM as a corrosion inhibitor of 7xxx series aluminum alloy was determined. EIS diagrams confirmed that cysteine showed better inhibition than Ce-Cys complex.

The aim of this work was to investigate corrosion resistivity, bioactivity, and antibacterial activity of novel nano-amorphous calcium phosphate (ACP) potentially multifunctional composite coatings with and without chitosan oligosaccharide lactate (ChOL), ACP + ChOL/TiO2 and ACP/TiO2 ACP + ChOL/TiO2, respectively, on the titanium substrate. The coatings were obtained by new single-step in situ anodization of the substrate to generate TiO2 and the anaphoretic electrodeposition process of ACP and ChOL. The obtained coatings were around 300 ± 15 μm thick and consisted of two phases, namely, TiO2 and hybrid composite phases. Both ACP/TiO2 and ACP + ChOL/TiO2 have improved corrosion stability, whereas the ACP + ChOL/TiO2 coating showed better corrosion stability. It was shown that at the very start of the deposition process, the formation of the ChOL/TiO2 layer takes place predominantly, which is followed by the inclusion of ChOL into ACP with simultaneous growth of TiO2. This deposition mechanism resulted in the formation of strongly bonded uniform stable coating with high corrosion resistance. In vitro bioactivity was investigated by immersion of the samples in simulated body fluid (SBF). There is in-bone-like apatite formation on both ACP/TiO2 and ACP + ChOL/TiO2 surfaces upon immersion into SBF, which was proven by X-ray diffraction and Fourier transform infrared spectroscopy. While ACP/TiO2 shows no antibacterial activity, ACP + ChOL/TiO2 samples exhibited three- to fourfold decreases in the number of Staphylococcus aureus and Pseudomonas aeruginosa, respectively, after 420 min. The probable mechanism is binding ChOL with the bacterial cell wall, inhibiting its growth, altering the permeability of the cell membrane, and leading to bacterial death.

The study is focused on the determination of the most effective chemical leaching process for the simultaneous demineralization/deashing and desulfurization of subbituminous coal from the Bogovina Basin. Coal was treated for 30 min, at different temperatures, using variable concentrations of hydrochloric, nitric, acetic and citric acids; hydrogen peroxide, mixture of hydrogen peroxide and nitric acid (pH 2), as well as by the stepwise leaching process (nitric acid + mixture of hydrogen peroxide and nitric acid, pH 2). The changes in mineral composition, caused by the chemical leaching, are followed using X-ray diffraction, whereas alterations of coal organic matter are tracked by Fourier-transform infrared spectroscopy and the content of fixed carbon. Inorganic acid leaching, regardless of the temperature and acid concentration, enabled the successful deashing of coal, whereas the percent of desulfurization was insufficient. The organic acid leaching was not satisfactory for both, deashing and desulfurization. Leaching by H2O2 and H2O2/HNO3 mixture (pH 2) resulted in moderate desulfurization, but the ash reduction was low. The most suitable method for the simultaneous effective ash (78 wt.%) and the sulfur (66 wt. %) removal from Bogovina coal is the two-step leaching, combining 10 vol. % HNO3 and mixture of 35 vol. % H2O2/10 vol. % HNO3 of pH 2 at 60°C.

The role and influence of strontium and its oxide on structure and capacitive response of materials containing mixed lanthanum cobalt oxides, LC, and lanthanum strontium cobalt oxides, LSC, as a capacitive materials were investigated in this study. The mixed oxides were synthesized by the single-step ultrasonic spray pyrolysis (USP) technique. The microstructures and electrochemical properties of the samples were characterized by X-ray diffraction, scanning electron microscopy, cyclic voltammetry, potentiostatic electrochemical impedance spectroscopy and galvanostatic charge/discharge cycling. It was found that strontium oxide induces the formation of the perovskite structure of promoted pseudocapacitive behavior over an enhancement of redox transitions of cobalt. The measurements showed that the capacitive stability and rate capability were lower for the samples of higher specific capacitance. Among the prepared materials, the LSC prepared at a USP temperature 600 °C showed the best capacitive characteristics in 0.10 M KOH due to having the most defined spherical perovskite structure leading to well-defined reversible charge–discharge performances.

The aim of this work was to investigate corrosion resistivity, bioactivity, and antibacterial activity of novel nano-amorphous calcium phosphate (ACP) potentially multifunctional composite coatings with and without chitosan oligosaccharide lactate (ChOL), ACP + ChOL/TiO2 and ACP/TiO2 ACP + ChOL/TiO2, respectively, on the titanium substrate. Supplementary information: The ANOVA results of antimicrobial activity on S. aureus are shown in Table S1 and the ANOVA results of antimicrobial activity on P. aeruginosa are shown in Table S2. The analysis showed significant difference at the 5% level of confidence.

In its pure form, aluminum is easy to process and has a high level of corrosion resistance. However, due to its low strength the possibility of application of pure aluminum is reduced. When alloyed, aluminum alloys are widely used material in construction, different industries, airspace and military. Commercial 7000 series aluminum alloys have zinc as the main alloying element, followed by magnesium. This 7000 aluminum series offers a very high strength when heat-treated, which comes from its composition. The life time of these alloys is reduced due to corrosion damage. It is known that corrosion directly or indirectly affects materials, human health and safety, and it causes global economic and environmental problem. The use of inhibitors in corrosion protection is the simplest, most economical and most efficient approach that is routinely used to ‘reduce’ this problem in industry. The most widely used inorganic inhibitors, such as chromates, are not safe, causing health and safety problems due to their toxicity. Organic compounds have increased interest of the scientific community as potential inhibitors in exchange for the most commonly used. The aim of this study was to investigate new green, eco-friendly inhibitors from the group of amino acid and their combination with lanthanides. For the purposes of this investigation, cerium-cysteine complex was synthesized and analyzed by Fourier-Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM / EDS), Potentiostatic Electrochemical Impedance Spectroscopy (PEIS) and Linear Sweep Voltammetry (LSV) analyses. SEM/EDS was used for morphological analysis and to determine the composition of the aluminum alloy on which the electrochemical tests have been performed. Electrochemical measurements (PEIS, LSV) were erformed in order to test the inhibitory efficacy in 0.1M NaCl at room temperature. Different concentrations of cysteine and Ce-cysteine complex were examined to

Four 2-thiohydantoin derivatives were synthesized and their corrosion inhibition properties on mild steel (MS) in 0.5M HCl solution was evaluated using usual gravimetric and electrochemical methods (weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS). Morphology of the metal surface was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The study has shown that these compounds provide good protection for mild steel against corrosion in the acidic medium.

In its pure form, aluminum is easy to process and has a high level of corrosion resistance. However, due to its low strength the possibility of application of pure aluminum is reduced. When alloyed, aluminum alloys are widely used material in construction, different industries, airspace and military. Commercial 7000 series aluminum alloys have zinc as the main alloying element, followed by magnesium. This 7000 aluminum series offers a very high strength when heat-treated, which comes from its composition. The life time of these alloys is reduced due to corrosion damage. It is known that corrosion directly or indirectly affects materials, human health and safety, and it causes global economic and environmental problem. The use of inhibitors in corrosion protection is the simplest, most economical and most efficient approach that is routinely used to ‘reduce’ this problem in industry. The most widely used inorganic inhibitors, such as chromates, are not safe, causing health and safety problems due to their toxicity. Organic compounds have increased interest of the scientific community as potential inhibitors in exchange for the most commonly used. The aim of this study was to investigate new green, eco-friendly inhibitors from the group of amino acid and their combination with lanthanides. For the purposes of this investigation, cerium-cysteine complex was synthesized and analyzed by Fourier-Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM / EDS), Potentiostatic Electrochemical Impedance Spectroscopy (PEIS) and Linear Sweep Voltammetry (LSV) analyses. SEM/EDS was used for morphological analysis and to determine the composition of the aluminum alloy on which the electrochemical tests have been performed. Electrochemical measurements (PEIS, LSV) were erformed in order to test the inhibitory efficacy in 0.1M NaCl at room temperature. Different concentrations of cysteine and Ce-cysteine complex were examined to

In chemical processes it is essential that the flow in the process is accurately defined. Fluid velocity measurements are important for fluid flow quality performance in flow systems. This study focuses on determination of the volumetric flow rate and its standard (relative) deviation for calibration of conventional flow meters by using a radiotracer approach. The measurements for flow meter calibration were performed at a pilot-scale flow rig using Technetium-99 m (99mTc) as a radiotracer in the form of pertechnetate ion (99mTcO4-). The measured data were analyzed, and precision of the experimental setup was investigated under two different approaches – IAEA’s RTD software and sum approximation of raw data. For the first time, the variation of standard deviation of calculated flow rate with the injection volume and activity of the radiotracer was determined. Plug flow with axial dispersion was used to simulate the measured RTD curves and investigate the flow dynamics of the flowing water. The results of the study have shown the possibility of in situ calibration of flow meters with a relative error lower than 1 %. They also revealed a slight dependency of the precision of output results on the injection volume as well as similar results for manual and specialized RTD software data processing., U hemijskim procesima od suštinskog značaja je tačno definisan i precizan protok. Merenja brzine fluida su važna za karakterizaciju kvaliteta protoka tečnosti u sistemima. Ova studija se fokusira na određivanje zapreminskog protoka i standardnog (relativnog) odstupanja izmerenih vrednosti u cilju kalibracije konvencionalnih merača protoka korišćenjem metode radioaktivnog obeleživača. Merenja potrebna za kalibraciju merača protoka izvedena su na pilot postrojenju korišćenjem Tehnecijuma-99m (99mTc) kao radiotrejsera u obliku pertehnetatnog jona (99mTcO4-). Izmereni podaci su analizirani, a preciznost eksperimentalne postavke je ispitivana pomoću dva različita pristupa: upotrebom softvera za određivanje raspodele vremena zadržavanja (eng. residence time distribution, RTD) koga je razvila Međunarodna agencija za atomsku energiju i zbirne aproksimacije neobrađenih podataka. Po prvi put je utvrđena varijacija standardne devijacije izračunatog protoka u odnosu na zapreminu i u odnosu na aktivnost ubrizganog radioaktivnog obeleživača. Model protoka sa aksijalnom disperzijom je korišćen za simulaciju izmerenih RTD krivih i istraživanje dinamike protoka vode. Rezultati studije su pokazali mogućnost in situ kalibracije merača protoka sa relativnom greškom manjom od 1%. Takođe su pokazali malu zavisnost preciznosti izlaznih rezultata od količine ubrizganog obeleživača, kao i slične rezultate za manuelnu obradu i specijalizovanu obradu podataka upotrebom RTD softvera.

In this paper novel in situ one-step simultaneous anaphoretic deposition process of amorphous calcium phosphate (ACP) and titanium oxide (TiOx) with and without chitosan oligosaccharide lactate (ChOL) on titanium substrate was performed. The coatings were investigated by SEM, XRD and FTIR techniques, whereas roughness and adhesion were measured. It was shown that novel process occurs, with improved coatings adhesion and excellent coverage of the surface. At 90 V the surface is smoother, and there is possibility for crystallization of the components at prolonged deposition times.

In this paper novel in situ one-step simultaneous anaphoretic deposition process of amorphous calcium phosphate (ACP) and titanium oxide (TiOx) with and without chitosan oligosaccharide lactate (ChOL) on titanium substrate was performed. The coatings were investigated by SEM, XRD and FTIR techniques, whereas roughness and adhesion were measured. It was shown that novel process occurs, with improved coatings adhesion and excellent coverage of the surface. At 90 V the surface is smoother, and there is possibility for crystallization of the components at prolonged deposition times.

Considerable promotion of RuO2 hosted by perovskite-like structure of rare earth–CoO3 composite and vice versa supercapacitive performances is reported. Spherical, sub-μm-sized, regular spheres of La0.6Sr0.4CoO3 (LSCO), were synthesized by ultrasonic spray pyrolysis. The sphere surface was subsequently hydrothermally doped by RuO2. LSCO and LSCO/RuO2 composites were investigated for their supercapacitive performances in alkaline solution. Microstructure and surface morphology were studied by SEM and XRD. It was found that amorphous Ru species decorate LSCO surface, and possibly incorporate partially into B-site of the LSCO lattice. Electrochemical characterization by cyclic voltammetry (CV), galvanostatic charge-discharge (G-C/DC) and electrochemical impedance spectroscopy (EIS) clearly revealed that capacitive performances of LSCO are considerably improved by addition of 20 mass. % of RuO2. The registered capacitance for LSCO/RuO2 reaches the values of pure RuO2, which reveals the promoting influence of LSCO on RuO2 pseudocapacitance. The EIS analysis showed that RuO2 catalyzes the redox transition of Co species, with simultaneous proportional increase in pseudocapacitive RuO2 abilities while being hosted by LSCO. This intrinsic interactive promotion introduces LSCO/RuO2 composite as unique supercapacitive material. G-C/DC curves showed that LSCO/RuO2 is of modest cyclability with respect to pure LSCO and RuO2, although the capacitance losses with cycling are acceptably low. © 2019 Elsevier Ltd

The optimization of the anodization process of Ti substrate for in situ synthesis of hydroxyapatite/titanium oxide composite coatings on titanium substrate was accomplished. The anodization was performed under 30, 60 and 90 V cell voltage, and the morphology of treated surface, as well as linear and surface roughness, were analysed by field emission-scanning electron micro­scopy, atomic force microscopy and roughness tester. It was shown by linear and surface roughness analyses that titanium anodized under 60 V has the high­est roughness, whereas at 90 V the flattening of the surface occurs. As the highest surface roughness results emerged at 60 V, the novel process of com­po­site anHAp/TiO2 coating synthesis, which comprises simultaneous processes of TiO2 formation and HAp deposition, as well as HAp impregnation within TiO2 surface layer, was performed at this voltage. Ti substrate surface was completely covered by composite coating, with no visible cracks. The adhesion quantified according to ASTM D3359-02 standard is considerably improved with respect to the coatings obtained by cathaphoretic processes, with no need of subsequent sintering.

In this study niobium oxide films were formed without peroxo-precursors from three different mixed acidic aqueous solutions on glassy carbon. Linear sweep voltammetry and potential step were techniques used for electrochemical experiments. The simultaneous and consecutive electrochemical reduction of water, nitrate and sulphate ions provided an alkaline environment with oxygen in the near vicinity of the working cathode, which in combination with the present niobium ions, produced niobium oxides and/or oxyhydroxides on the glassy carbon substrate. The formed deposits were analyzed using scanning electron microscopy and energy dispersive spectroscopy and appear to consist of NbO, NbO2 and Nb2O5. Both the niobium and acid concentration of the electrolytes used influenced the morphology and particle size of the deposits. The formation of niobium-fluoride and hydrogen-niobiumoxide complexes is addressed.

New biopolymers’ materials, suitable for the adsorption of noble metal ions, were synthesized by chemical and electrochemical modification of biopolymers. Optimization of cellulose acrylate synthesis by reaction with sodium cellulosate and acryloyl chloride was carried out. Optimal conditions for conducting the synthesis reaction of cellulose acrylate were as follows: the molar ratio of cellulose/potassium-t-butoxide/acryloyl chloride was 1:3:10 and the optimal reaction time was 10 h. On the basis of elemental analysis with optimal conditions for conducting the reaction of cellulose acrylate, the percentage of substitution of glucose units in cellulose was Y = 80.7%, and the degree of substitution of cellulose acrylate of DS = 2.4 was determined. The grafting reaction of acrylate vinyl monomers onto cellulose in acetonitrile with azoisobutyronitrile initiator in a nitrogen atmosphere was performed, by mixing for 5 h at acetonitrile boiling temperature. Radical copolymerizations of synthesized cellulose acrylate and 4-vinylpyridine, 1-vinylimidazole, 1-vinyl-2-pyrrolidinone, 9-vinylcarbazole, cellulosepoly-4-vinylpyridine, cellulose-poly-1-vinylimidazole, cellulose-poly-1-vinyl-2-pyrrolidinone and cellulose-poly-9-vinylcarbazole were performed. Cellulose acrylate and cellulose grafted copolymers were confirmed by IR spectroscopy, based on elementary analysis and the characteristics of grafted copolymers of cellulose were determined. The mass share of grafted copolymers, X, the relationship of derivative parts/cellulose vinyl group, Z, and the degree of grafting copolymers of cellulose (mass%) were determined. The grafed copolymers of cellulose with 4-vinylpyridine and 1- vinylimidazole were reacted with methyl iodide and the corresponding 1 - methylpyridinium iodide and 3-methylimidazolium iodide copolymers of cellulose were obtained. Copolymers were transformed into new polymeric reagents, differing in anions (ClO4-, CF3COO-, NO3-, p-TsO-, BF4-, PF6-) by usage of di

Composite materials nowdays are increasing industrial applications worldwide. Composites based on polymers with conductive fillers are getting wider research focus primarily because of their growing importance from the point of application in: electronics, medicine, industry and so on. Besides mentioned above, these composites have found application as contact conductive materials, electromagnetic and radio wave shields, photothermal optical recorders, electronic noses sensitive to certain chemicals, as well as economically acceptable catalysts. The results of experimental studies of the properties of composite materials based on lignocellulosic (LC) and Poly(methyl methacrylate) (PMMA) matrices filled with electrolytic copper are presented in this chapter. Volume fractions of metal fillers in tested composite materials were varied in the range of 1.6–30% (v/v), and the samples were prepared both by compression – cold pressing and hot moulding. The results have shown that shape and morphology of the copper powder, and filler at all, play a significant role in the phenomenon of electrical conductivity of the prepared samples, as well as on the appearance of percolation threshold. The particles with highly developed free surface areas like dendrites, having highly branched structures (such as electrolitically obtained copper powder particles) can much easier form interparticle contacts at lower filler volume fractions than the particles with more regular surface. Layered electrical conductivity throughout the entire sample volume was observed, whereby the resistance of the inner layers was the leading processes of the entire composite resistance. It can be seen that the resistance has increased due to increased contribution of the polymer matrix inner surface area as the frequency decreased. Conductivity measurements have shown typical S-shaped dependence with the percolation transition from nonconductive to conductive region. For all the processing pressures, the per

This manuscript presents the results of investigating the properties of composite materials having poly(lactide-co-glycolide) (PLGA) matrix filled with electrolytically produced copper powder whose particles have a highly developed branched structure. The volume fraction of the copper powder used as a filler for the preparation of the composite was varied from 0.4 to 7.2 vol. %. The samples were prepared at 140 °C by hot molding injection. The effect of the morphology of electrolytically obtained copper powder on the appearance of the percolation threshold and on the conductivity of the composites was studied. Characterization included impedance spectroscopy (IS) measurement of electric conductivity and scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and Fourier-transform Infrared Spectroscopy (FTIR) morphological analysis. Electric conductive pathways were formed throughout the entire volume of the composites, where their formation was purely stochastic in all the dimensions. The percolation threshold was 2.72 vol.%, which is significantly lower than the one stated in the literature for similar composites, since these kind of composites are investigated for the first time. This property can be attributed to the use of a filler of different, diverse morphologies.

In-situ synthesis of HAp/TiO2 coating on titanium was performed via anaphoretic deposition of HAp and simultaneous anodization of Ti to produce highly adherent and strengthened composite coating. The prepared coatings were characterized by field emission scanning electron microscopy, X-ray diffraction and electron dispersive spectroscopy. HAp on anodized titanium was prepared at constant voltage of 60 V and deposition time of 45 s, which provided uniform and adherent HAp/TiO2 composite coating on Ti. Since smaller size of HAp crystals within highly porous coating structures is of improved binding ability to various biomolecules, our coating is expected to be of excellent coverage and compactness. The obtained coating can be good candidate for bone implants due to reduced brittleness and improved adhesion.

The medical devices based on titanium and its alloys are widely used in the repair and replacement of a degraded or inhibited func-tion of locomotor system [1]. Ti and its alloys exhibit high mechanical strength, good workability, resistant to corrosion and low cost. Although, they are widely used as orthopedic and dental implants their inability to interact with living tissue will inhibit their biological fixation and osseoin-tegration [2]. Therefore, to improve the hard-tissue compatibility of Ti various sur-face treatments have been developed for the inorganic coating formation [3]. The hyd-roxyapatite (HAp, Ca10(PO4)6(OH)2) with superior osteogenic activity is a competitive approach to make novel coatings for titanium implants applications. HAp is a calcium phosphate very similar to the inorganic part of the human bone and hard tissues both in morphology and compo-sition. Herein, in-situ synthesis of HAp/TiO2 coating on titanium was performed via ana-phoretic deposition of HAp and simulta-neous anodization of Ti to produce highly adherent and strengthened composite coating. It can be seen that morphology of Ti substrate of anHAP/TiO2 coating is of tubular shape, and tube formation occurs mainly due to competing processes of anodization and electrophoretic deposition of HAp. anHAp/TiO2 coating does not need sintering process, and simultaneous Ti anodization and HAp deposition occur, where HAp crystals incorporate in the anodized Ti surface. From the presented results it can be concluded that novel suggested process of in situ simultaneous anHAp/TiO2 deposition with Ti surface anodization gives much better results that cathaphoretic deposition regarding adhesion.

Titanium substrates were electrochemically treated by novel in-situ synthesis method to produce anaphoretic hydroxyapatite/titanium oxide (HAp/TiO2) coating. This synthesis method was performed via anaphoretic deposition of hydroxyapatite and simultaneous anodization of Ti in order to produce highly adherent and strengthened composite coating, where the influence of electric potential, time, electrolyte concentration and pH value of the anodization process on titanium surface roughness and adhesion strength of composite HAp/TiO2 coatings was examined. In situ synthesis was performed in different solutions containing different concentrations of NaOH, HAp and ethanol at different values of time and constant voltage. The effects of anodizing voltage on the morphology and bioactivity of the HAp coating and on the bonding strength between the HAp coating and the anodized substrates were investigated. A modified chemical precipitation method was used to prepare hydroxyapatite powder by the reaction of stoichiometric amount of calcium oxide and phosphoric acid. Prior to novel in situ synthesis of HAp/TiO2 composite coatings, optimization of anodization process of titanium was performed. Anodization was executed under different electric potentials and different distances of counter electrodes from working electrodes, but all experiments had constant quantity of electric charge. Results indicated that highly ordered amorphous TiO2 surface is formed on the Ti substrate after anodic oxidation. Characterization of titanium samples having rectangular contact surfaces of 10×10×0.89 mm included SEM/EDS analyses, X-ray diffraction analyses, AFM surface topography, morphology and roughness analyses and linear measurements of roughness. The prepared coatings were characterized by FE-SEM, XRD and EDS. Adhesion was investigated by ASTM D 3359–97 Test method B. Uniform and adherent HAp/TiO2 composite coating on Ti was obtained. The results of simulated body fluid immersing experiments s

The optimization of the anodization process of Ti substrate for in situ synthesis of hydroxyapatite/titanium oxide composite coatings on titanium substrate was accomplished. The anodization was performed under 30, 60 and 90 V cell voltage, and the morphology of treated surface, as well as linear and surface roughness, were analysed by field emission-scanning electron micro­scopy, atomic force microscopy and roughness tester. It was shown by linear and surface roughness analyses that titanium anodized under 60 V has the high­est roughness, whereas at 90 V the flattening of the surface occurs. As the highest surface roughness results emerged at 60 V, the novel process of com­po­site anHAp/TiO2 coating synthesis, which comprises simultaneous processes of TiO2 formation and HAp deposition, as well as HAp impregnation within TiO2 surface layer, was performed at this voltage. Ti substrate surface was completely covered by composite coating, with no visible cracks. The adhesion quantified according to ASTM D3359-02 standard is considerably improved with respect to the coatings obtained by cathaphoretic processes, with no need of subsequent sintering.

In-situ synthesis of hydroxyapatite/titanium oxide (HAp/TiO2) coating on titanium was performed via anaphoretic deposition of hydroxyapatite (HAp) and simultaneous anodization of Ti to produce highly adherent and strengthened composite coating. The influence of electric potential, time, electrolyte concentration and pH value of the anodization process on titanium surface roughness and anodization of titanium was examined, as well as influence of same process parameters on adhesion strength and compactness of composite HAp/TiO2 coatings was investigated. Prior to novel in situ method of synthesis of hydroxyapatite/titanium oxide composite coatings by simultaneous anodization/anaphoretic electrodeposition described in this manuscript, optimization of anodization process of titanium was performed. Anodization was executed under different electric potentials and different distances of counter electrodes from working electrodes, but all anodization processes had constant quantity of electric charge. Characterization of titanium samples, prepared from grade 6 Ti, and having rectangular contact surfaces of 10×10×0.89 mm included SEM/EDS analyses, X-ray diffraction analyses, AFM surface topography, morphology and roughness analyses and linear measurements of roughness. A chemical precipitation method was used to prepare hydroxyapatite powder by the reaction of calcium oxide (obtained by calcination of CaCO3 for 5 h at 1000 °C in air) and phosphoric acid. A stoichiometric amount of the calcium oxide was stirred in distilled water and phosphoric acid was added drop wise to the suspension in order to obtain hydroxyapatite powder, Ca10(PO4)6(OH)2. Two types of HAp coatings were prepared, in order to compare the adhesion, morphology and consistency of the HAp and composite HAp/TiO2 on Ti, namely cathaphoretic and anaphoretic coatings, respectively [1,2]. The prepared coatings were characterized by field emission scanning electron microscopy, X-ray diffraction and electron disper