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Transition metal carbides have gathered increasing attention in energy and electrochemistry applications, mainly due to their high structural and physicochemical properties. Their high refractory properties have made them an ideal candidate coating technology and more recently their electronic similarity to the platinum group has expanded their use to energy and catalysis. Here, we demonstrate that the nanostructuring and stoichiometry control of the highest melting point material to this date (Ta-Hf-C) results in outstanding electrochemical stability. Our results show one of the largest windows of stability of a single component electrode in a broad range pH. These experiments provide a new perspective on the electrochemical, thermoelectric and mechanical behavior of Ta-Hf-C nanocomposites, towards a broad range of applications in energy production, catalysis and analytical chemistry., E.C. acknowledges the partial financial support of the National Science Center (NCN) of Poland under the OPUS grant (UMO-2019/35/B/ST5/00248). K.Z. acknowledges the partial financial support from the National Science Centre of Poland by the SONATA Project No. UMO-2016/23/D/ST3/02121. K.S. acknowledges the partial financial support of NCN under the SONATA-BIS grant (2017/26/E/ST5/00416). B.G. and V.B acknowledge the partial financial support of the foundation for polish science (FNP) under the FIRST TEAM program (POIR.04.04.00-00-5D1B/18). Y.K. acknowledges the partial financial support by Basic Science Research Program through the National Research Foundation (NRF) funded by the Ministry of Education (NRF-2017R1A6A1A06015181) of Republic of Korea. J.S.R. and B. D.: acknowledge financial support from the Spanish Ministry of Economy, Industry, and Competitiveness through the “Severo Ochoa” Program for Centers of Excellence in R&D (SEV-2015-0496), and MAT2017-90024-P (TANGENTS)-EI/FEDER., With funding from the Spanishgovernment through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).

TiWSixN films were deposited using a magnetron co-sputtering system on silicon (111), 316L stainless steel, and M2 high-speed steel substrates. The silicon target current density was varied from 0 mA/cm2 to 4.32 mA/cm2 in order to modify the Si content in the films. The microstructure and chemical composition were determined by means of X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. The surface of the films was explored via scanning electron microscopy (SEM) and atomic force microscopy (AFM). Mechanical, tribological, and thermal properties were investigated by means of the nanoindentation, ball-on-disc, and cyclic oxidation tests, respectively. Our results indicated that as the silicon target current density was increased, the microstructure changed from crystalline to amorphous, and the hardness and elastic modulus improved from initial values of 7.5 ± 0.3 GPa and 181 ± 8 GPa to 15 ± 1 GPa and 229 ± 9 GPa, respectively. Furthermore, films deposited at high silicon target current exhibited better resistance to thermal oxidation. The failure mechanism of the WTiSixN thin films under cyclic oxidation was attributed to the microstructure of the films, WO3 sublimation, and the thermal coefficient mismatch between the film and the substrate.

Poly(ethylene glycol) (PEG) chains were covalently grafted onto carbon black (CB) using a PEG-terminated trimethoxysilane, yielding PEGylated CB additives (CB-SiPEG) with different SiPEG contents. Unlike pristine CB, CB-SiPEG was readily dispersed in PEG200 base oil, with CB-SiPEG hydrodynamic particle sizes being considerably smaller than those of pristine CB. At optimal SiPEG content, friction coefficient and specific wear rate in ball-on-disk tribometer tests were reduced by 35% and 67% respectively, with 1% wt. CB-SiPEG compared to PEG200 alone. In contrast, pristine CB, alone or with unbound SiPEG, did not show friction-reducing or antiwear capacity. Disk analysis supports CB-SiPEG surface deposition forming a protective tribofilm. Hydrodynamic particle size and lubricating performance of CB-SiPEG/PEG200 blends were preserved after 6 months, indicating high dispersion stability.

Ruthenium oxide (RuO2) has received significant attention in recent years for its photocatalytic properties and photoelectrochemical (PEC) performance. In the present research, RuO2 nanolayers were grown on n-type porous silicon (PSi) by metal organic chemical vapor deposition (MOCVD) and atomic layer deposition (ALD). The morphology, mechanical and optical properties of produced nanostructures were studied by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), micro-Raman spectroscopy, diffuse reflectance and photoluminescence (PL) spectroscopy. It was shown that that MOCVD gives non-uniform distribution of RuO2 along the pore and it is deposited mainly in the near-surface of PSi, while distribution of ruthenium obtained by ALD looks conformal over the entire pore. The mean size of RuO2 nanocrystallites and mechanical stresses were determined by TEM, XRD and Raman spectroscopy. It was demonstrated that samples obtained by ALD demonstrate a good crystallinity, while crystalline phase for samples produced by MOCVD improve with RuO2 layer thickness increasing. It was established the formation of hydrated RuO2 during ALD and MOCVD. It was shown that the samples produced by MOCVD have slightly higher electrical conductivity than ALD samples. The average value of energy gap (Eg) for samples prepared by MOCVD depended on the number of injections. RuO2 nanolayers quenched intrinsic PL from the PSi matrix. The correlation between structural, optical, and mechanical properties of samples produced by MOCVD and ALD was discussed.

The room temperature synthesis of copper (Cu) nanoparticles (NPs) supported within SiO2 mesoporous thin films (MTF) modified with either COOH or NH2 functional groups is reported. The functional groups present in the MTF surface acted as adsorption sites for Cu (II) ions, which were afterwards reduced to Cu NPs in presence of sodium borohydride at room temperature. The oxidation state of the copper NPs, corroborated by X-ray Photoelectron Spectroscopy and Electron Energy Loss Spectroscopy, was strongly dependent on the functional group present in the pores of the MTF and on the number of adsorption/reduction (A/R) cycles applied for NPs loading. Metallic Cu (0) NPs were obtained in MTFs displaying COOH groups applying 10 A/R cycles while NPs with higher oxidation state were as well present after 20 A/R cycles. For MTF functionalized with NH2 groups the copper is present as Cu (I) and Cu(II) in the NPs but no Cu (0) can be detected. The MTF-Cu(CuOx) composite materials were tested as catalysts for the reduction of 4-nitrophenol in the presence of NaBH4. Catalytic activity of composite materials depends on the oxidation state of Cu NPs, being more active those samples containing Cu (0) NPs, synthesized from COOH functionalized MTFs. Fil: Coneo Rodríguez, Rusbel. Comisión Nacional de Energía Atómica. Gerencia del Área de Seguridad Nuclear y Ambiente. Gerencia de Química (CAC); Argentina. Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología; Argentina Fil: Yate, Luis. No especifíca; Fil: Coy, Emerson. Adam Mickiewicz University; Polonia Fil: Martínez Villacorta, Ángel M.. No especifíca; Fil: Bordoni, Andrea Veronica. Comisión Nacional de Energía Atómica. Gerencia del Área de Seguridad Nuclear y Ambiente. Gerencia de Química (CAC); Argentina. Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología; Argentina Fil: Moya, Sergio. No especifíca; Fil: Angelome, Paula Cecilia. Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Seguridad Nuclear y Ambiente. Gerencia de Química (CAC); Argentina

Polyacrylic acid (PAA) brushes synthesized by reversible addition fragment chain transfer (RAFT) polymerization on titania (TiO2) surfaces were applied for the surface confinement and slow delivery of strontium (Sr2+) ions during the osseointegration process on TiO2 surfaces. Sr2+ is an essential element in the bone remodeling cycle and has large potential for application in therapies for bone-related diseases and bone replacement. Sr2+ complexation to the carboxylate groups of PAA was demonstrated by XPS while Sr2+ release in media was studied by ICP-MS. The Sr2+ concentration was varied by preparing PAA brushes at two grafting densities. At the higher grafting density, the brushes offer more carboxyl groups for Sr2+ binding. The architecture of the brushes and the amount of Sr2+ is controlled by the density of polymer chains. The morphology and brush thickness were characterized by AFM and ellipsometry. The significant effects of PAA brush coated TiO2 complexing Sr2+ on osteoblast cells is shown. The use of PAA brushes for Sr2+ confinement restricts Sr2+ activity to the cells in direct contact with the TiO2 surface. Initial adhesion of osteoblast cells is superior on coatings with brushes compared to bare TiO2. Moreover, a rather rapid cell tissue formation is observed for the cells cultured on the brushes with higher Sr2+ content. Enhanced biocompatibility and osseoactivity is confirmed by an increased alkaline phosphatase activity.

Transition metal carbide alloys are promising materials to replace platinum as electrodes in electrocatalysts toward the hydrogen evolution reaction (HER). Although tantalum hafnium carbides (Ta-Hf...

We investigate the deposition of TiWSiNx thin films by means of the method of reactive magnetron co-sputtering, setting the nitrogen flow ratios N2/(Ar + N2) at 4.8%, 9.1%,16.7 and 33.3%. The crystallographic structure of the films was established through X-ray diffraction (XRD), the morphology and topography were evaluated through scanning electron microscopy (SEM) and atomic force microscopy (AFM), the chemical composition was evaluated through X-ray diffraction and X-ray photoelectron spectroscopy, the mechanical properties were evaluated by nanoindentation, and the wear resistance was studied via nanowear and pin-on-disk. It was found that films deposited between 4.8% and 16.7% nitrogen flow ratio exhibited an amorphous phase. As the nitrogen was increased, the films evolved into a mixture of amorphous Si3N4 and crystalline TiWN phase. Moreover, the film morphology changed to fine columnar as the nitrogen flow ratio increased. As a general observation, the hardness, resistance to plastic deformation (H3/E2), and residual stress of the samples increased as the nitrogen flow ratio increased. The maximum hardness, resistance to plastic deformation, and residual stress were 22 ± 0.4 GPa, 213 ± 20 MPa, and 1.4 ± 0.01, respectively. The lowest nanowear volume (0.47 µm3) and wear rate (11 ± 8 10−9 mm3/N mm) were obtained for films deposited at high nitrogen flow ratios. The lowest friction coefficient (0.15) was recorded for films deposited at 16.7% nitrogen flow ratio.

Polymer brushes have a great potential for controlling surface wetting properties. In this work we study the surface wettability in respect to water of diblock copolymer brushes with an outer block of the thermoresponsive poly(N-isopropylacrylamide) (PNiPAM) polymer and an inner hydrophobic block of 1H 1H 2H 2H-perfluorodecyl Acrylate (PPFDA) and with variable block lengths. Block copolymer brushes are synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization. The conditions of synthesis; polymerization time of NiPAM, grafting density of change transfer agent (CTA) on the surface, amount of initiator and monomers were varied to produce brushes with different ratios of PNiPAM and PPFDA. Diblock copolymer brushes are characterized by Raman, XPS and Atomic Force Microscopy. Brushes with contact angles from 28 to 85 degrees are produced. The brushes with longer PPFDA blocks are the more hydrophobic. Contact angle values increase when raising temperature from 20 °C to 40 °C as for PNiPAM but always to higher contact angles than for the PNiPAM brush.

International audience; Structural, electronic and mechanical properties of ZnO/Graphene (ZnO/G) nanolaminates fabricated by low temperature atomic layer deposition (ALD) and chemical vapor deposition (CVD) were investigated. We performed scanning and transmission electron microscopy (SEM/TEM), X-ray diffraction (XRD), electron energy loss spectroscopy (EELS), Raman spectroscopy, X-Ray photoelectron spectroscopy (XPS) and nanoindentation to characterize the ZnO/G nanolaminates. The main structural and mechanical parameters of ZnO/G nanolaminates were calculated. The obtained results were analyzed and interpreted taking into account mechanical interaction and charge effects occurring at the G-ZnO interface. The influence of graphene sublayers number on the mechanical behavior of the ZnO/G nanolaminates was studied. By reducing the bilayer thickness, the mechanical parameters of the films can be tuned (Young's modulus 100-200 GPa, hardness 3-9 GPa). The softer response of the multilayers as compared to the single layers of ZnO and graphene was attributed to the structural changes in the ZnO layer and the interfaces. This study shows the mechanical behavior of ZnO/G nanolaminates and their influence on the development of novel electro-optical devices based on these structures. (C) 2018 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

The use of silver nanoparticles (AgNPs) result in an inevitable contact with aquatic environments. Here we study the behavior of AgNPs and the developmental toxicity in zebrafish embryos exposed to these nanoparticles (0-10 mg/L) with and without the presence of HA (20 mg/L), using zebrafish facility water (ZFW) and zebrafish growing media (ZGM). The presence of cations and HA gave rise to a decrease in Ag ion release and ζ-potential, an increase in the hydrodynamic diameter and oxidation of the AgNP surface. The results show that the presence of HA and cations in the media, as well as the silver speciation, i.e., the unusual presence of Ag3+, decreases the toxicity of AgNPs (LC50AgNPs: 1.19 mg/L; LC50AgNPs + HA: 3.56 mg/L), as well as silver bioavailability and toxicity in zebrafish embryos. Developmental alterations and the LC50 (1.19 mg/L) of AgNPs in ZFW were more relevant (p ≤ 0.05) than for AgNPs in ZGM (LC50 ˃ 10 mg/L). It was demonstrated that the bioaccumulation and toxicity of AgNPs depends on several factors including AgNPs concentration, nanoparticle aggregation, dissolved silver ions, speciation of silver ions, the amount of salt in the environment, the presence of humic substances and others, and different combinations of all of these factors.

A study has been conducted based on the Mott-Schottky model acquisition by potentiodynamic electrochemical impedance spectroscopy, to determine the physical-chemical properties of binary TiO2, Nb2O5 and ternary Nb-Ti-O thin films (semiconductor type) based on Nb,Ti, O elements. The technique used for the study of optical properties was that of spectral transmittance, measurements were performed using a spectrophotometer. The consistency of the impedance data has been studied by calculating the Kramers-Kronig relations. The structural properties were analyzed by XRD patterns; the chemical composition measurements for all thin films were made by using XPS technique. So, in this research the transmittance values change from 72.74% for Nb2O5 to 59.68% for Ti-Nb-O with wavelength around 355 nm. The absorption coefficients for all films were analyzed from 31823.87 cm−1 for Nb2O5 to 91240.90 cm−1 for Nb-Ti-O with wavelength around 355 nm evidencing thus a 65% reduction. The direct band gap it was found that the photon energy (band gap Eg) changes in all films from 3.56 eV for Nb2O5 to 3.96 eV for Ti-Nb-O evidencing a 10% reduction. The extinction coefficient values change in all films from 0.038 cm−1 for Nb2O5 to 0.277 cm−1 for Ti-Nb-O films with wavelength around 355 nm, exhibiting an 86% increasing. Finally, it was observed by the Mott-Schottky analysis that the reference potential (Ag/AgCl) changes for all films from −2.09 V for Nb2O5 to −0.80 V for Ti-Nb-O material showing a 62% reduction. Keywords: Mott-Schottky, Thin films, Titanium oxide, Niobium oxide, Semiconductor properties

In this study, an osteogenic environment was constructed on Ti alloy implants by in-situ formation of nanosized fibrous titanate, Na2Ti6O13, loaded with bioactive ions, i.e. Sr, Mg and Zn, to enhance surface bioactivity. The bioactive ions were loaded by ion exchange with sodium located at inter-layer positions between the TiO6 slabs, and their release was not associated with the degradation of the structural unit of the titanate. In-vitro cell culture experiments using MC3T3-E1 cells proved that both bioactive ions and nanotopographic features are critical in promoting osteogenic differentiation of the cells. It was found that the osteogenic functions of the titanate can be modulated by the type and amount of ions incorporated. This study points out that nanosized fibrous titanate formed on the Ti alloy can be a promising reservoir for bioactive ions. The major advantage of this approach over other alternatives for bioactive ion delivery using degradable bioceramic coatings is its capacity of maintaining the structural integrity of the coating and thus avoiding structural deterioration and potential mechanical failure.

A Taguchi L16(45) orthogonal array design was selected to determine the influence of the deposition parameters on the mechanical properties, wear volume, and corrosion resistance of TiWSiN thin films. The power applied to the silicon-tungsten target, nitrogen to argon flow ratio (N2:Ar), substrate temperature, and bias voltage were set to four levels for depositing the films using co-sputtering equipment. The hardness, wear volume, and corrosion resistance were evaluated via nanoindentation, reciprocating-sliding, and potentiodynamic polarization, respectively. The microstructure, chemical composition, and morphology were also studied, by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The obtained results were transformed into signal-to-noise ratios (S/N), and an analysis of variance (ANOVA) was performed. It was found that the power applied to the silicon target was the factor that makes the greatest difference in the evaluated films’ properties. According to the combination of factors, nanocomposite structure and FCC and BCC crystalline structures were detected. Almost all of the films exhibited columnar growth; however, the columns’ width was affected as the deposition conditions were modified.

In this work, we report the first observation of novel nanocomposite thin films consisting of nanocrystalline chromium embedded in an amorphous chromium carbide matrix (nc-Cr/a-CrC) with relatively high hardness (∼22,3 GPa) and ultra low nanowear. The films were deposited onto silicon substrates using a magnetic filtered cathodic arc deposition system at various negative bias voltages, from 50 to 450 V. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) suggested the co-existence of chromium and chromium carbide phases, while high resolution transmission electron microscopy (HRTEM) confirmed the presence of the nc-Cr/a-CrC structure. The friction coefficient measured with the ball-on disk technique and the nanowear results showed a strong correlation between the macro and nano-tribological properties of the samples. These novel nanocomposite films show promising properties as solid lubricant and wear resistant coatings with relatively high hardness, low friction coefficient and ultra low nanowear.

It has been long known that the physical encapsulation of oleic acid-capped iron oxide nanoparticles (OA–IONPs) with the cetyltrimethylammonium (CTA+) surfactant induces the formation of spherical iron oxide nanoparticle clusters (IONPCs). However, the behavior and functional properties of IONPCs in chemical reactions have been largely neglected and are still not well-understood. Herein, we report an unconventional ligand-exchange function of IONPCs activated when dispersed in an ethyl acetate/acetate buffer system. The ligand exchange can successfully transform hydrophobic OA–IONP building blocks of IONPCs into highly hydrophilic, acetate-capped iron oxide nanoparticles (Ac–IONPs). More importantly, we demonstrate that the addition of silica precursors (tetraethyl orthosilicate and 3-aminopropyltriethoxysilane) to the acetate/oleate ligand-exchange reaction of the IONPs induces the disassembly of the IONPCs into monodispersed iron oxide–acetate–silica core–shell–shell (IONPs@acetate@SiO2) nanoparticles. Our observations evidence that the formation of IONPs@acetate@SiO2 nanoparticles is initiated by a unique micellar fusion mechanism between the Pickering-type emulsions of IONPCs and nanoemulsions of silica precursors formed under ethyl acetate buffered conditions. A dynamic rearrangement of the CTA+–oleate bilayer on the IONPC surfaces is proposed to be responsible for the templating process of the silica shells around the individual IONPs. In comparison to previously reported methods in the literature, our work provides a much more detailed experimental evidence of the silica-coating mechanism in a nanoemulsion system. Overall, ethyl acetate is proven to be a very efficient agent for an effortless preparation of monodispersed IONPs@acetate@SiO2 and hydrophilic Ac–IONPs from IONPCs.

In this study ZnPc@TiO2 hybrid nanostructures, both nanoparticles and nanotubes, as potential photosensitizers for the photodynamic therapy, fluorescent bioimaging agents, as well as anti-cancer drug nanocarriers, were prepared via zinc phthalocyanine (ZnPc) deposition on TiO2. In order to provide the selectivity of prepared hybrid nanostructures towards cancer cells they were modified with folic acid molecules (FA). The efficient attachment of both ZnPc and FA molecules was confirmed with dynamic light scattering (DLS), zeta potential measurements and X-ray photoelectron spectroscopy (XPS). It was presented that ZnPc and FA attachment has a strong effect on fluorescence emission properties of TiO2 nanostructures, which can be further used for their simultaneous visualization upon cellular uptake. ZnPc@TiO2 and FA/ZnPc@TiO2 hybrid nanotubes were then employed as doxorubicin nanocarriers. It was demonstrated that doxorubicin can be easily loaded on these hybrid nanostructures via an electrostatic interaction and then released. In vitro cytotoxicity and photo-cytotoxic activity studies showed that prepared hybrid nanostructures were selectively targeting to cancer cells. Doxorubicin loaded hybrid nanostructures were significantly more cytotoxic than un-loaded ones and their cytotoxic effect was even more severe upon irradiation. The cellular uptake of prepared hybrid nanostructures and their localization in cells was monitored in vitro in 2D cell culture and tumor-like 3D multicellular culture environment with fluorescent confocal microscopy. These hybrid nanostructures preferentially penetrated into human cervical cancer cells (HeLa) than into normal fibroblasts (MSU-1.1) and were mainly localized within the cell cytoplasm. HeLa cells spheroids were also efficiently labelled by prepared hybrid nanostructures. Fluorescent imaging of Hela cells treated with doxorubicin loaded hybrid nanostructures showed that doxorubicin was effectively delivered into cells, released and evenly distributed in the cytoplasm. In conclusion, prepared hybrid nanostructures exhibit high potential as selective bioimaging agents next to their photodynamic activity and drug delivery ability.

Gd2(MoO4)3 (GMO) is a well-studied multiferroic material that exhibits full ferroelectric and ferroelastic behavior at room temperature. However, its difficult stabilization in thin films has prevented the study and exploitation of its multiferroic properties in different architectures. Here, we report on the study of GMO thin films deposited on Si(001) substrates by Pulsed Laser Deposition (PLD). The physicochemical properties of the films are discussed and studied. Results obtained by X-ray diffraction, X-ray photoelectron spectroscopy, high resolution transmission microscopy and second harmonic generation show that the orthorhombic (β′-GMO) multiferroic phase can be stabilized and homogenized by post deposition thermal reconstruction. Finally, the reconstruction process takes place via a complex surface mechanism with a clear leaf-like behavior.

Inorganic–organic hybrid mesoporous silica thin films with covalently bonded carboxylic acid groups were synthesized in a one-step procedure, using carboxylic-derivatized alkoxysilanes obtained by photochemical radical thiol-ene addition (PRTEA). The organosilanes were synthesized by clicking mercaptosuccinic or mercaptoacetic thioacids with vinyltrimethoxysilane, using benzophenone as the photoradical initiator. The films were synthesized by evaporation-induced self-assembly of a sol containing a mixture of tetraethoxysilane and different quantities of the organosilanes, without any further treatment after the PRTEA reaction. Two nonionic surfactants were used as templates to produce different pore sizes. Different aging times were also applied. Structural characterization with electron microscopy, porosimetry measurements, and small angle X-ray scattering with two-dimensional detection demonstrated the obtention of mesoporous phases whose degree of ordering depended on the amount of added organosilane. The incorporation of the functional silanes was shown by X-ray photoelectron spectroscopy, and the presence of the COOH groups was confirmed by Fourier transform infrared (FTIR). Finally, the availability of the COOH groups for further chemical modification was demonstrated by FTIR by following the changes in the typical carbonyl IR bands during proton exchange and metal complexation. The proposed simple methodology allows obtaining COOH-modified silica thin films in one step, without the need of hard reaction conditions or deprotection steps. Functionalization with carboxyl groups brings a pH-dependent switch-ability to the pore surface that can be used for multifunctional mesoporous materials design.

Calcite, the most stable polymorph of calcium carbonate (CaCO3), attracts growing attention due to its wide applications in many fields, such as composite materials, food industry, biomineralization, and dating of archeological and geological objects. Our study shows the influence of UV, X-ray and γ-radiation on the mechanical and physicochemical properties of calcite at the nanoscale. Using nanoindentation technique we observed a clear detriment in the mechanical response (hardness and elastic modulus) of the calcite (104) surface after irradiation, most visible in the case of UV. Changes in mechanical properties were correlated with the accumulation of radiation defects detected using EPR spectroscopy, and information on chemical bonding and composition obtained through XPS analyses. Additionally, the efficiency in generating defects for all three types of radiation was compared, which allowed us to propose a possible mechanism of UV-induced formation of radiation defects in calcite.

Portable screen-printed carbon electrodes (SPCE) were uniformly modified with TiO2 and Au nanoparticles (TiO2-AuNPs-SPCE). Synthetized AuNPs were characterized by TEM, showing an average diameter of 17.9 ± 2.3 nm. The doped electrodes were characterized using scanning electron microscopy, X-ray photoelectron and Raman spectroscopy. Cyclic voltammetry (CV) performed using as model analytes: an inorganic ([Fe(CN)6]3−/4−) and an organic (catechol) redox probe showed a drastic enhanced of the electrodes electrochemical surface activity and suggested a synergistic catalytic effect between Au NPs and TiO2. Additionally, the electrochemical performance was evaluated for other hydroxyphenols such as hydroquinone, pyrogallol and dopamine. In the case of hydroquinone, the electron transfer rate constant for TiO2-AuNPs-SPCE was estimated to be almost three times faster than for bare SPCE. The results for dopamine also demonstrated remarkably enhanced activity (up to 50%) respect to the non-modified SPCE, showing lower oxidation peak potentials and peak-to-peak separations, as well as, sharper peak current intensities at the TiO2-AuNPs modified SPCE.

The design of ultrafine, highly efficient and recyclable heterogeneous bimetallic nanoparticles catalysts is challenging. In this work, we report for the first time the preparation of ultrafine and monodispersed bimetallic RhAg nanoparticles that are uniformly supported on reduced graphene oxide (rGO) nanosheets (RhAg/rGO). A key is the presence of the tris(triazolyl)-polyethylene glycol (tristrz-PEG) ligand as a weak stabilizing agent. This amphiphilic tridentate ligand not only enables the formation of ultrafine RhAg NPs, but also allows quantitative fixation of the NPs onto the rGO, which avoids metal loss and further improves catalytic efficiency. The RhAg/rGO catalysts were characterized by various techniques including UV–Vis, ICP-AES, TEM, HRTEM, STEM, EDX and XPS. By varying the molar ratios of Rh to Ag, the highest catalytic activity in the reduction of 4-nitrophenol by NaBH4 was obtained for RhAg0.5/rGO with a remarkable reaction rate of k app = 14.8 × 10−3 s−1 (k nor = 1415 s−1 g−1). Moreover, the catalyst was recycled, and its amount was reduced to 100 ppm of RhAg0.5/rGO while retaining an exceptional catalytic efficiency. The present work contributes to the effective design of ultrafine bimetallic NPs/graphene-based nanocomposites and to the fabrication of very efficient and cost-effective catalysts.

The antioxidant activity of graphene quantum dots (GQD) with different chemical composition and sp 2 -hybridized carbon content has been evaluated and compared to that of a standard antioxidant, ascorbic acid. GQD were prepared by top down and bottom up synthetic approaches from three different precursors (carbon black, glucose and pyrene) in order to vary significantly the chemical composition, electron density and sp 2 -hybridized carbon content. For a given radical, the three types of GQD exhibited very different radical scavenging activity (RSA). Moreover, the RSA varied with the type of free radical and reactive oxygen species (ROS) tested, indicating different radical inhibition mechanisms. Overall, GQD with strong hydrogen donor behavior and large content of sp 2 –hybridized carbon domains were the most effective radical scavengers. Thus, highly graphitic GQD with abundant edge functional groups produced from pyrene exhibited an extraordinary high antioxidant activity, with inhibition effective concentrations much lower than those of ascorbic acid. The great potential of highly antioxidant GQD as protective films against organic dye decoloration by ROS was demonstrated with two model target molecules, methylene blue and rhodamine B.

The impact of polyanions on the formation of lipid bilayers on top of polyelectrolyte multilayers (PEMs) with poly(allylamine hydrochloride) (PAH) as the top layer is studied for the deposition of vesicles of mixed lipid composition, 50:50 molar ratio of zwitterionic 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and negatively charged 1,2-dioleoyl-sn-glycero-3-phospho-L-serine (DOPS). PEMs are assembled with polystyrene sulfonate (PSS), poly(acrylic acid) (PAA), and alginic acid sodium salt (Alg) as polyanions. The assembly of the vesicles on the PEMs is followed by means of the quartz crystal microbalance with dissipation. Fluorescence recovery after photobleaching measurements are applied to evaluate bilayer formation. Whereas a bilayer is formed on top of PAH/PSS multilayers, the vesicles are adsorbed on top of PAH/Alg and PAH/PAA multilayers, remaining unruptured or only partially fused. The influence of the surface composition of the PEM and of the bulk properties of the film are analyzed. The phosphate ions present in phosphate-buffered saline (PBS) play a fundamental role in bilayer formation on top of PAH/PSS as they complex with PAH and render the surface potential close to zero. For PAH/PAA and PAH/Alg, PBS renders the surface negative. X-ray photoelectron spectroscopy shows that the dibasic phosphate ions from PBS complex preferentially with PAH in PAH/PAA and PAH/Alg multilayers, whereas monobasic phosphates complex with PAH in PAH/PSS. An explanation for the absence of bilayer formation on PAH/PAA and PAH/Alg is given on the basis of the different affinities of phosphate ions for PAH in combination with the different polyanions.

International audience; Due to their wide bandgap, boron nitride (BN) thin films are the focus of interest for their potential applications in microelectronic devices. The reliability of these devices is essential and is directly linked to the mechanical properties of the films used for their fabrication. Herein, an atomic layer deposition (ALD) process based on sequential pulses of BBr3 and NH3 at 750 °C is used in order to prepare BN thin films. We report the main physicochemical properties of the films using various analytical methods. We also performed nanoindentation experiments in order to determine the elastic modulus and the hardness. Next, we annealed the films at 1000 and 1350 °C in order to gain understanding on the relation between the annealing temperature, the microstructure obtained and the resulting mechanical properties. Although the hardness of the films presents similar values of 5 ± 1 GPa for all temperatures, it has been found that the elastic modulus increases up to 150 ± 9 GPa when applying an annealing treatment of 1350 °C, which represents a 37% improvement compared to the initial film prepared at 750 °C.

New PEG-stabilized CuNP catalysts are designed upon Cu(II) reduction with sodium naphthalenide in MeCN followed by simple purification using the salting-out effect. Their catalytic activity in CuAAC is boosted upon 30 min exposure to air, producing Cu2O NPs. These NPs are also supported on SBA-15, providing excellent recyclable heterogeneous catalysts that are applied in low amounts for efficient “click” functionalization.

Epitaxial thin films of double perovskite Y(Ni 0.5 Mn 0.5 )O 3 (001) and Y(Ni 0.5 Mn 0.5 )O 3 (101) grown on SrTiO 3 (001) and SrTiO 3 (111), respectively, were studied by XPS and SQUID magnetometer. Temperature dependent Ti diffusion was detected in the Y(Ni 0.5 Mn 0.5 )O 3 (101)/SrTiO 3 (111) samples, while no diffusion was observed in Y(Ni 0.5 Mn 0.5 )O 3 (001)/SrTiO 3 (001) samples. It was observed that the use of a low ablation rate promoted ionic migrations, mainly due to the associated annealing time that samples undergo when grown at lower rates. The migration speed was determined by XPS analysis and its influence on the magnetic properties of the Y(Ni 0.5 Mn 0.5 )O 3 (101) films was characterized and discussed.

A simple and versatile method to produce filtration membranes with graphene quantum dots (GQD) and their excellent performance as turn-off fluorescence sensing platforms for Cr (VI) detection in water is presented. Suitably functionalized GQD were immobilized on various types of membranes (nylon, cellulose and glass fiber) and the resulting GQD-modified membranes exhibited the characteristic fluorescence fingerprint of the GQD probes. The membrane fluorescence was quenched by highly toxic Cr (VI) ions due to selective coordination to GQD functional groups. The analytical performance of membranes was comparable to that of dispersed GQD fluorescent probes, displaying a fast and linear response to Cr (VI) concentration in the 1–500 μM range, a low detection limit of 190 nM, high sensitivity, reproducibility and selectivity. Moreover, the membranes can be regenerated by simple washing with deionized water and reused, preserving their good sensing response after several Cr (VI) detection-washing cycles. Membrane sensing performance was very stable after being immersed in water for several days and filtering water through them.

We report on the deposition and characterization of hard and wear resistant orthorhombic Cr3C2 thin films. Films are deposited using a novel linear filtered cathodic arc (LFCA) at high energetic conditions and relatively low substrate temperatures (

The positive electrodes based on nano- and micrometric carbon coated LiFePO 4 (LFP) powders are prepared via aqueous slurry processing using “normal” and “intensive” mixing procedures. The XRD, XPS, and electrochemical characterization reveal that the “intensive” mixing process improves the discharge C-rate capability of the n-LFP cathode however provokes formation of an undesirable thin surface layer enriched by Fe 3+ species. The waterborne graphite anodes and LiFePO 4 cathodes for the energy and power cells are being developed, upscaled and manufactured on a pilot plant. Energy LiFePO 4 /C pouch cells demonstrate outstanding durability maintaining 80% of initial discharge capacity (IDC) after 7450 and 2400 full cycles under 1D and 4D discharge currents, respectively. Moreover, further cycling of the energy cell working under 1C/4D protocol reveals its extra-long secondary life (70% of IDC on 9200 th cycle). Power LiFePO 4 /C pouch cell shows long lasting cycle life retaining 80% of IDC after 3350 cycles under harsh cycling conditions (3C/8D). The reported results are being achieved despite confirmed water release from lithium iron phosphate cathodes to the electrolyte. Finally, viability of aqueous processing of the electrodes without sacrificing electrochemical performance of LiFePO 4 /C batteries is clearly proven.

Normal micro-movements at the bone-implant interface originate fretting-corrosion processes, thus releasing wear debris from the bone and metallic devices and compromising the fixability of the implant. Titanium aluminum nitride (Ti 1− x Al x N) coatings have been considered to overcome these drawbacks and the effect of aluminum content on the fretting-corrosion resistance against bone in a simulated body fluid has been studied. Coatings were synthesized by magnetron co-sputtering by varying the power applied to the aluminum target. Morphology and chemical composition were studied by optical profilometry, SEM and XPS. Coatings with x =0.39, 0.47, 0.61 and 0.69 were obtained. Mechanical properties, adherence and corrosion behavior were assessed by nanoindentation, scratch test and potentiodynamic curves, respectively. The fretting-corrosion behavior was assessed at open circuit potential (OCP) using a tribo-electrochemical apparatus, bone-pins as the counterpart and Hank׳s solution as the simulated body fluid. It was found that the fretting-corrosion against bone in the simulated body fluid can damage the metal and coatings, thereby accelerating wear and increasing the current corrosion densities. Coatings with x =0.39, 0.47 and 0.61 are able to protect 304SS against fretting corrosion. The behavior of wear volume with aluminum content in coatings is related to the corrosion resistance and hardness to elastic modulus ratio.

The grafting of well-defined polystyrene to graphene oxide (GO) using nitroxide-mediated polymerization (NMP) is demonstrated by a two-step reaction. In the first step, GO is functionalized with glycidyl methacrylate (GMA) to yield GO-GMA. Polystyrene (PS), previously synthesized via SG1-based NMP, is then grafted to GO-GMA by a simple reaction between the SG1 end group and the GMA double bond to yield GO-GMA-g-PS. 1H, heteronuclear single-quantum correlation (HSQC), nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy (XPS), Raman, Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), and thermogravimetric analysis (TGA) are consistent with attachment of the GMA group to the GO surface and with polystyrene being grafted to the GO surface to form the GO-GMA-g-PS nanocomposite (NC). GPC analysis shows a number-average molecular weight of 3330 g mol−1 for the PS with molecular weight dispersity (Ð) of 1.13. Up to 28 mass% of PS has been introduced into the GO NC. The present “grafting-to” methodology holds promise for the facile and clean synthesis of graphene oxide polymer NCs.

Novel bioactive calcium titanate–tricalcium phosphate–tetracalcium phosphate composite coatings were developed. Powder mixtures of hydroxyapatite and 25, 50 and 75 vol% of calcium titanate were uniaxially pressed and sintered at 1100–1200 °C for 4 h. After heat treatment, the composites, which consisted of calcium titanate and oxyhydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2−2 x O x □ x ), were evaporated by magnetron sputtering to coat an AISI 304/Ti buffer layer substrate. Calcium phosphate (CP) and calcium titanate (CT) coatings were also produced for comparison. The surface topography of the composite coatings was observed by SEM and AFM. Their structure and composition were evaluated by XRD, FTIR and XPS, and the re-assembly process of the atoms from composite targets to the coatings was emphasized. Nanoindentation experiments were carried out to measure the hardness. Coated samples were immersed in a simulated body fluid (SBF) for 30 days under physiological conditions of pH and temperature for the in-vitro bioactivity assessment. Finally, because the coatings are proposed for orthopedic applications, the cytotoxicity of the coatings was examined with human osteoblasts. It was found that calcium titanate coating is harder than the calcium phosphate coating, the 75–25 composite coatings fit a rule of mixture of hardness, and the rougher coatings contained a larger amount of nano-scale precipitated apatite. Furthermore, all the coatings were not cytotoxic. The results indicate that 75%CP–25%CT coating is a potential material for bone tissue replacement and regeneration.

The development of a pretreatment system to assist surface plasmon sensor-based measurement of arsenic in water is described. The system proposed addresses important issues, regarding the reliable in situ detection of arsenic in water. This system uses a primary filter made of nonactivated cotton fibers for particulate matter and chemical retention agents without modifying the arsenic concentration in the water sample. A secondary filter was designed for retention of mercury, lead, and other heavy metals without alteration of the arsenic concentration in the collected water samples to be sensed. This filter was made with amino-functionalized carbon nanotubes. The results of the operational assessment of this filter show a retention efficiency of 98% for suspended solids, 96% for mercury ions, and 2% for arsenic, a remarkable improvement toward the accurate detection and quantification of arsenic in contaminated waters.

Thanks to their unique properties, such as (i) renewability, (ii) high aspect ratios, (iii) low density, (iv) biodegradability, (v) high strength, and (vi) stiffness, there have been many reports in recent years detailing the isolation and functionalization of cellulose nanowhiskers from cellulose. Moreover, nanocellulose can be produced in large quantities in a cost-effective manner and can be easily functionalized due to its high density of hydroxy groups. In the present work, alkynyl-dendrons of the PAMAM family were covalently attached to azide-functionalized cellulose nanocrystals by click chemistry (Huisgen cycloaddition). The resulting cycloadducts were then used as templates for the preparation of stable and monodispersed gold nanoparticles in aqueous media. The catalytic capabilities of these hybrid materials were studied in the sodium borohydride mediated reduction of 4-nitrophenol to 4-aminophenol, which served as a model reaction.

High temperature composite target AlN–TiB2–TiSi2 with heterogeneous distribution of compounds (AlN—50 wt.%; TiB2—35 wt.%; TiSi2—15 wt.%) is used for sputtering via combined reactive/non-reactive DC magnetron sputtering onto substrate materials either cylindrical polished steel (Fe, 18%—Ni, 12%—Cr, 10%—Ti) 3 mm diameter or monocrystalline silicon. The gradient coating has been produced by sequential non-reactive and reactive sputtering of the target. The structural and morphological properties of the deposited films are analyzed by transmission electron microscopy, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. The tribo-mechanical properties are studied by means of nanoindentation and nanowear tests. The gradient film is composed of two layers with different microstructure and elemental composition. The first layer with thickness ~200 nm is mainly based on light B, C and N as well metal elements Al, Si and Ti. The presence of very well distributed nanocrystals embedded in an amorphous matrix, with crystal sizes ranging from 5 to 40 nm is observed in the second layer ~700 nm thickness and composed of Al, Ti, Si, B, and N. Films show very flat surfaces, with roughness around 0.35 nm. The hardness, elastic modulus, elastic recovery (We), H/E⁎ ratio and H3/E⁎2 ratio are determined as 17.55 GPa, 216.7 GPa, 60%, 0.08 and 0.12 GPa, respectively. Nanowear tests demonstrate relatively high wear resistance of the coatings. Samples show promising characteristics for hard protective adaptive coatings and diffusion barriers due to short propagation of dislocations in the amorphous matrix and the elastic and hard nature of the nanocomposite structure. Keywords: Hard coatings, Nanocomposite, Functionally graded film, Nanoindentation, Wear test

Titanium aluminium nitride (Ti1−xAlxN) coatings are utilized in industrial applications because of their excellent tribological and anticorrosive properties. Recently these coatings have been proposed for biomedical applications. In this paper, the biocompatibility and bioactivity of Ti1−xAlxN coatings, having various aluminium contents, x, deposited on AISI 304SS stainless steel, have been studied. Coatings were synthesized by magnetron co-sputtering by varying the power applied to the aluminium target. Morphology, chemical composition and microstructure were studied by SEM, AFM, XPS and XRD. Biocompatibility was assessed by measuring haemolytic and cytotoxic characteristics. Haemolysis was measured following the ASTM F756 norm. The in vitro cytotoxicity was assessed with human osteoblasts by means of the lactate dehydrogenase (LDH) release assay. Bioactivity was measured by soaking the samples in a simulated body fluid (SBF) and analysing the surfaces by XPS, XRD and SEM. It was found that all the Ti1−xAlxN coatings exhibited good biocompatibility and bioactivity, precipitating hydroxyapatite and monetite. The aluminium content in the Ti1−xAlxN coatings increases the quantity of calcium and phosphates groups precipitated in the beginning of the process, but it was also observed an influence of the roughness in the quantity of apatite precipitated after 1 month of immersion in SBF. The coating with x = 0.69 exhibited the higher bioactivity.

In this work Hf–C–N coatings were deposited on silicon substrates by reactive R.F. magnetron co-sputtering from two hafnium and carbon targets in a reactive nitrogen atmosphere at various negative bias voltages from 0 to 150 V. The effect of the bias voltage on the chemical composition, crystalline structure and mechanical properties was studied by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), Raman spectroscopy, X-ray diffraction (XRD) and nanoindentation. The results show that the obtained films have a Hf /( C + N ) ratio of around 1 and present an evolution with the bias voltage from a quasi-amorphous structure, with a low hardness (6 GPa) to crystalline Hf 2 CN films with a high hardness (23 GPa) and electrical resistivity values in the order of 10 4 Ω·cm − 1 . This study shows the potential for hard and electrically conductive Hf–C–N films in industrial applications.

The influence of the surface chemistry of polyelectrolyte multilayers (PEMs) on the formation of lipid bilayers is studied here for PEMs with either polyallylamine hydrochloride (PAH) or polydiallyldimethylammonium chloride (PDADMAC) as a polycation as a top layer, and polystyrene sulfonate (PSS) as a polyanion. Small unilamellar vesicles (SUVs) composed of phosphatidyl choline and phosphatidyl serine at a 50 : 50 molar ratio are deposited on top of the PEM films. The assembly of the SUVs into bilayers is studied via a quartz crystal microbalance with dissipation (QCM-D) and fluorescence recovery after photobleaching (FRAP). SUV deposition on PDADMAC/PSS results in vesicle adsorption while on PAH/PSS under the same conditions a bilayer is formed mainly due to weak interactions between the quaternary amines of PDADMAC. FRAP measurements confirm that SUVs are not fused on top of PDADMAC/PSS. The effect of phosphate ions, in solution, on the formation of lipid bilayers is also analysed. X-ray photoelectron spectroscopy shows the complexation of phosphate salts to the primary amines of PAH and no interaction with the quaternary amines of PDADMAC. ζ-potential measurements show a potential close to 0 for the PAH/PSS multilayers in PBS while PDADMAC/PSS displays a potential of 25 mV. A model is presented for the formation of lipid bilayers on PAH/PSS PEMs taking into account the role of phosphate ions in decreasing the electrostatic interactions between SUVs and PEMs and the formation of hydrogen bonds between the phospholipids and the primary amines of PAH.

Here, a platform for the development of highly responsive organic–inorganic enzyme hybrids is provided. The approach entails a first step of protein engineering, in which individual enzymes are armored with a porous nanogel decorated with imidazole motifs. In a second step, by mimicking the biomineralization mechanism, the assembly of the imidazole nanogels with CuSO4 and phosphate salts is triggered. A full characterization of the new composites reveals the first reported example in which the assembly mechanism is triggered by the sum of Cu(II)–imidazole interaction and Cu3(PO4)2 inorganic salt formation. It is demonstrated that the organic component of the hybrids, namely the imidazole‐modified polyacrylamide hydrogel, provides a favorable spatial distribution for the enzyme. This results in enhanced conversion rates, robustness of the composite at low pH values, and a remarkable thermal stability at 65 °C, exhibiting 400% of the activity of the mineralized enzyme lacking the organic constituent. Importantly, unlike in previous works, the protocol applies to the use of a broad range of transition metal cations (including mono‐, di‐, and trivalent cations) to trigger the mineralization mechanism, which eventually broadens the chemical and structural diversity of organic–inorganic protein hybrids., This project had received funding from the Spanish Ministry of Economy and Competitiveness (MINECO) and the FEDER funds in the frame of “Plan Nacional – Retos para la Sociedad” call with the Grant Reference No. MAT2017‐88808‐R. This work was performed under the Maria de Maeztu Units of Excellence Programme – Grant No. MDM‐2016‐0618. A.B. thanks Diputación de Guipúzcoa for current funding in the frame of Gipuzkoa Fellows program. M.K. acknowledges financial support by the Spanish Ministry of Economy and Competitiveness (MINECO) within Grant Agreement No. MAT2016‐77393‐R, including FEDER funds.

The aim of this work was to investigate the potential of pegylated poly(anhydride) nanoparticles to enhance the oral bioavailability of docetaxel (DTX). Nanoparticles were prepared after the incubation between the copolymer of methyl vinyl ether and maleic anhydride (Gantrez® AN), poly(ethylene glycol) (PEG2000 or PEG6000) and docetaxel (DTX). The oral administration of a single dose of pegylated nanoparticles to mice provided sustained and prolonged therapeutic plasma levels of docetaxel for up 48–72 h. In addition, the relative oral bioavailability of docetaxel was around 32%. The organ distribution studies revealed that docetaxel underwent a similar distribution when orally administered encapsulated in nanoparticles as when intravenously as Taxotere®. This observation, with the fact that the clearance of docetaxel when loaded into the oral pegylated nanoparticles was found to be similar to that of intravenous formulation, suggests that docetaxel would be released at the epithelium surface and then absorbed to the circulation.

An ideal dental implant coating should provide a highly protective interface and an osteogenic function. Inspired by the excellent biocompatibility and anti-corrosion of the Nb element, we produced Nb-based oxide, nitride and carbide films as well as the pure metal Nb film for surface enhancement of dental implants, and compare the impact of the nonmetal elements on the electrochemical, tribological, tribo-corrosion and biological performance of the coated implants. The NbC film, composed of a single-phased subniobium carbide, displays mechanical advantages and anticorrosion characteristics that are distinguished from the other composite films, highlighting its potential outstanding protective efficiency for dental implants against corrosion and wear. Rat bone marrow mesenchymal stem cells (rBMSCS) were found more readily to attach, grow and osteogenically differentiate on the NbC film compared to the Nb, NbO and NbN films, indicating the osteogenesis potential of the NbC film. Taken all the results together, it can be concluded that the NbC film have the highest potential for dental implant surface modification.

An innovative electrochemical route is proposed to obtain CuI films. The approach is based on the electrochemical reduction of I2 in a solution of copper bis(trifluoromethanesulfonyl)imide salt in 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide room temperature ionic liquid. The mechanisms involved in the deposition process are analyzed by cyclic voltammetry, pointing out that the CuI formation occurs from the chemical reaction between the Cu2+ and I- generated from the I2 reduction. Homogenous films constituted of open-packed primary CuI nanocrystals (~100 nm) are obtained. The electrodeposition from organic solvent-based media is also investigated, finding that the solvent nature affects strongly to the nanocrystal packing density. Compact CuI thin films are electrodeposited from the isopropanol-based electrolytes. The electrodeposition of ZnO/CuI heterostructures, with high transmittance in the visible range (i.e. > 75%), is also reported. The current density-voltage characteristic of the resulting device exhibits clear rectifying behavior, with a rectification of ~ 2x103 at V = ± 1.5 V. This result anticipates a significant potential of the present electrochemical route to obtain CuI films with competitive optoelectronic functionalities. Keywords: CuI, Electrodeposition, Ionic liquid, Halide semiconductor

In this study Fe-doped TiO2 (0.35 to 3.50 wt% Fe) nanotubes (NTs) were prepared as the potential photosensitizer for near-visible light driven photodynamic therapy (PDT) against cervical cancer cells (HeLa). Characterization of the prepared nanotubes by X-ray diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) confirmed the successful incorporation of Fe3+ as a dopant into the TiO2 matrix, which was mainly composed of an anatase phase, while elemental mapping using energy dispersive X-ray spectroscopy (EDX) showed homogenous distribution of the dopant ions in TiO2 for both low and high doping levels. UV-Vis studies showed that Fe doping in TiO2 increases the light absorption within the visible range, particularly in the case of 0.70 and 1.40 wt% Fe–TiO2 and provides additional energy levels within the band gap, which promotes the photo-excited charge transport towards the conduction band. Photo-cytotoxic activity of the prepared Fe-doped TiO2 NTs was investigated in vitro against cervical cancer cells (HeLa) and compared with human normal fibroblasts (GM07492). Fe-doped TiO2 NTs exhibited no or lower dark cytotoxicity than un-doped TiO2 NTs, which confirms their superior biocompatibility. Under the near-visible light irradiation (∼405 nm) Fe-doped TiO2 NTs showed higher photo-cytotoxic efficiency than un-doped TiO2 NTs, which was found to be dependent on the NTs concentration, but not on the incubation time of cells after near-visible light irradiation. The highest activity was observed for 0.70 and 1.40 wt% Fe–TiO2 NTs. Fluorescent labeling of treated HeLa cells showed distinct morphological changes, particularly in the perimitochondrial area suggesting a mitochondria-involved apoptosis of cells, but also the nuclei and cytoskeleton were subject to Fe–TiO2 NTs induced photo-damage. Apoptosis of PDT treated HeLa cells was also confirmed using ethidium homodimer (EthD-1).

Thin films of ferromagnetic Y(Ni0.5Mn0.5)O3 (YNMO) perovskite were grown on different SrTiO3 (STO) substrate orientations [i.e. (0 0 1), (1 1 0) and (1 1 1)] by means of pulsed laser deposition (PLD) and their morphological and functional properties were studied and characterized. Optimal deposition parameters were identified and their individual influence on the quality of the films was also addressed. Films showed a single out-of-plane orientation in all the substrate scenarios, while the in-plane texture in STO(0 0 1) and STO(1 1 1) show two and three in plane domains, respectively. Growth mechanism and morphology were studied by HRTEM and AFM. As a result, a clear 3D growth mechanism was identified and a direct correlation between the two in-plane crystalline domains on the surface morphology of the sample was observed. Magnetic response of the films was investigated as a function of their crystalline properties. The films were found to have a paramagnetic to ferromagnetic transition around 90 K consistent with their bulk counterparts. Finally, the discrepancies on the epitaxial growth between YMnO3 (YMO) and YMNO thin films were clarified and tabulated, giving a clear picture of the effect of Ni substitution in the epitaxial and crystalline properties of manganites of this family.