Role of EDTA protonation in chelation-based removal of mercury ions from water.

A robust method of hazardous metal ion removal from an aqueous environment involves the use of chelating agents, such as ethylenediaminetetraacetic acid (EDTA). Here, we focus on mercury (Hg) uptake by EDTA using both molecular dynamics and density functional theory simulations. Our results indicate that the deprotonation of the EDTA carboxylate groups improves the localization of negative charge on the deprotonated sites.

Effect of Plasmonic Ag Nanoparticles on Emission Properties of Planar GaN Nanowires.

The combination of plasmonic nanoparticles and semiconductor substrates changes the properties of hybrid structures that can be used for various applications in optoelectronics, photonics, and sensing. Structures formed by colloidal Ag nanoparticles (NPs) with a size of 60 nm and planar GaN nanowires (NWs) have been studied by optical spectroscopy. GaN NWs have been grown using selective-area metalorganic vapor phase epitaxy.

Fragmented graphene synthesized on a dielectric substrate for THz applications.

Fragmented multi-layered graphene films were directly synthesized via chemical vapor deposition (CVD) on dielectric substrates with a pre-deposited copper catalyst. We demonstrate that the thickness of the sacrificial copper film, process temperature, and growth time essentially influence the integrity, quality, and disorder of the synthesized graphene. Atomic force microscopy and Kelvin probe force microscopy measurements revealed the presence of nano-agglomerates and charge puddles.

Mechanical relaxation of functionalized carbosilane dendrimer melts.

Functionalizing the internal structure of classical dendrimers is a new way of tailoring their properties. Using atomistic molecular dynamics simulations, we investigate the rheological behavior of functionalized dendrimer (FD) melts obtained by modifying the branching of carbosilane dendrimers (CSD). The time (relaxation modulus ()) and frequency (storage ' and loss '' moduli) dependencies of the dynamic modulus are obtained.

Dual-center co-doped and mixed ratiometric LuVO:Nd/Ybnanothermometers.

During last decade luminescence thermometry has become a widely studied research field due to its potential applications for real time contactless temperature sensing where usual thermometers cannot be used. Special attention is paid to the development of accurate and reliable thermal sensors with simple reading. To address existing problems of ratiometric thermometers based on thermally-coupled levels, LuVO:Nd/Ybthermal sensors were studied as a proof-of-concept of dual-center thermometer obtained by co-doping or mixture.

Upconverting NIR-to-NIR LuVO:Nd/Yb Nanophosphors for High-Sensitivity Optical Thermometry.

Accurate contactless thermometry is required in many rapidly developing modern applications such as biomedicine, micro- and nanoelectronics, and integrated optics. Ratiometric luminescence thermal sensing attracts a lot of attention due to its robustness toward systematic errors. Herein, a phonon-assisted upconversion in LuVO:Nd/Yb nanophosphors was successfully applied for temperature measurements within the 323-873 K range via the luminescence intensity ratio technique.

Al solvation in solutions of aluminum nitrate in a protic ionic liquid: Nuclear magnetic resonance verification of the solvation shell composition.

The closest environment of Al cations was analyzed in detail in solutions of aluminum nitrate in the prototypical protic ionic liquid ethyl ammonium nitrate (EAN) using H and N nuclear magnetic resonance (NMR) spectra. For Al (NO ) -EAN mixtures with different water content, a quantitative analysis of the integral intensities of the H and N signals was carried out and the composition of the first solvation shell of the aluminum cation was refined.

Effect of crystal structure on the Young's modulus of GaP nanowires.

Young's modulus of tapered mixed composition (zinc-blende with a high density of twins and wurtzite with a high density of stacking faults) gallium phosphide (GaP) nanowires (NWs) was investigated by atomic force microscopy. Experimental measurements were performed by obtaining bending profiles of as-grown inclined GaP NWs deformed by applying a constant force to a series of NW surface locations at various distances from the NW/substrate interface. Numerical modeling of experimental data on bending profiles was done by applying Euler-Bernoulli beam theory.

Modification Approaches to Enhance Dehydration Properties of Sodium Alginate-Based Pervaporation Membranes.

Transport characteristics of sodium alginate (SA) membranes cross-linked with CaCl and modified with fullerenol and fullerene derivative with L-arginine for pervaporation dehydration were improved applying various approaches, including the selection of a porous substrate for the creation of a thin selective SA-based layer, and the deposition of nano-sized polyelectrolyte (PEL) layers through the use of a layer-by-layer (Lbl) method. The impacts of commercial porous substrates made of polyacrylonitrile (PAN), regenerated cellulose, and aromatic polysulfone amide were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM), standard porosimetry method, and water filtration. The effects of PEL combinations (such as poly(sodium 4-styrene sulfonate) (PSS)/SA, PSS/chitosan, PSS/polyacrylic acid, PSS/poly(allylamine hydrochloride)) and the number of PEL bilayers deposited with the Lbl technique on the properties of the SA and SA/fullerene derivative membranes were studied by SEM, AFM, and contact angle measurements.

Gd-Doping Effect on Upconversion Emission of NaYF: Yb, Er/Tm Microparticles.

β-NaYF microcrystals co-doped with Yb, Er/Tm, and Gd ions were synthesized via a hydrothermal method using rare-earth chlorides as the precursors. The SEM and XRD data show that the doped β-NaYF form uniform hexagonal prisms with an approximate size of 600-800 nm. The partial substitution of Y by Gd results in size reduction of microcrystals.

Novel Mixed Matrix Sodium Alginate-Fullerenol Membranes: Development, Characterization, and Study in Pervaporation Dehydration of Isopropanol.

Novel mixed matrix dense and supported membranes based on biopolymer sodium alginate (SA) modified by fullerenol were developed. Two kinds of SA-fullerenol membranes were investigated: untreated and cross-linked by immersing the dry membranes in 1.25 wt % calcium chloride (CaCl) in water for 10 min.

Construction of efficient dual activating ratiometric YVO:Nd/Eu nanothermometers using co-doped and mixed phosphors.

The development of new contactless thermal nanosensors based on a ratiometric approach is of significant interest. To overcome the intrinsic limitations of thermally coupled levels, a dual activation strategy was applied. Dual activation was performed using co-doped single nanoparticles and a binary mixture of single-doped nanoparticles.

Local dynamics in LiCl-CsCl-DO water-in-salt solutions according to NMR relaxation.

The main purpose of this study was to investigate the local structure and dynamics in 'water-in-salt' solutions, namely the ternary concentrated LiCl-CsCl-D2O electrolytes. Water based electrolyte solutions are components of natural waters, they are very widespread and possess many practical abilities. NMR was applied as the main technique to study the local structure of the solutions as well as ion and solvent dynamics.

Stable Deuterium Labeling of Histidine-Rich Lysine-Based Dendrimers.

Peptide dendrimers, due to their biocompatibility and low toxicity, are highly promising candidates as nanocarriers for drugs and genes. The development of this kind of delivery system requires reliable monitoring of their metabolic and biological pathways. In this respect, hydrogen isotope labeling has tremendous importance, being a safe tool for detection of the labeled nanocarriers.

Lysine-based dendrimer with double arginine residues.

Due to their well-defined structure, multivalency, biocompatibility, and low toxicity, lysine dendrimers can be used as safe and efficient nanocarriers for drug and gene delivery. One useful strategy for improving the gene delivery properties of dendrimers is modification with arginine amino acid (Arg) residues. Incorporation of Arg residues could be favorable for the enhancement in transfection efficiency of lysine based dendrimers.

Effect of Domain Structure of Segmented Poly(urethane-imide) Membranes with Polycaprolactone Soft Blocks on Dehydration of -Propanol via Pervaporation.

Segmented poly(urethane-imide)s (PUIs) were synthesized by polyaddition reaction and applied for preparation of membranes. Tolylene-2,4-diisocyanate, pyromellitic dianhydride, and -phenylenediamine for chain extension were used to form hard aromatic blocks. Polycaprolactone diols with molecular weights equal to 530 and 2000 g mol were chosen as soft segments.

Magnetotransport and conductivity mechanisms in CuZnSnGeS single crystals.

Resistivity, ρ(T), and magnetoresistance (MR) are investigated in the CuZnSnGeS single crystals, obtained by the chemical vapor transport method, between x = 0-0.70, in the temperature range of T ~ 50-300 K in pulsed magnetic field of B up to 20 T. The Mott variable-range hopping (VRH) conductivity is observed within broad temperature intervals, lying inside that of T ~ 80-180 K for different x.

High-temperature magnetism and microstructure of a semiconducting ferromagnetic (GaSb) (MnSb) alloy.

We have studied the properties of relatively thick (about 120 nm) magnetic composite films grown by pulsed laser deposition using the eutectic compound (GaSb)(MnSb) as target for sputtering. For the studied films we have observed ferromagnetism and an anomalous Hall effect above room temperature, confirming the presence of spin-polarized carriers. Electron microscopy, atomic and magnetic force microscopy results suggest that the films under study have a homogenous columnar structure in the bulk while MnSb inclusions accumulate near the surface.

Plasticizing of chitosan films with deep eutectic mixture of malonic acid and choline chloride.

Chitosan (CS) films containing deep eutectic solvent (DES) based on malonic acid (MA) and choline chloride (ChCl) were successfully prepared by solution casting method by using DES content ranging from 0 to 82 wt%. A strong interaction of CS with the components of DES was demonstrated by analyses of water sorption isotherms, atomic force microscopy and FTIR results. The plasticizing effect of the MA and ChCl mixture on the CS matrix was shown by static bulk mechanical measurements, thermal analysis and quantitative nanomechanical mapping (QNM).

Molecular mobility in several imidazolium-based ionic liquids according to data of H and C NMR relaxation.

Temperature dependences are compared for H and C NMR 1/T curves relaxation rates in three imidazolium-based ionic liquids (ILs), namely, in [bmim]PF , [bmim]BF , and [emim]CH COO. C curves show alike behavior for all three ILs and follow a well-known Bloembergen-Pound-Purcell (BPP) equation. On the contrary, an essential part of H curves differ strongly from corresponding C ones and also have different shapes for different ILs.

Mechanisms of charge transfer and electronic properties of CuZnGeS from investigations of the high-field magnetotransport.

Recent development of the thin film solar cells, based on quaternary compounds, has been focused on the Ge contain compounds and their solid solutions. However, for effective utilization of CuZnGeS, deeper investigations of its transport properties are required. In the present manuscript, we investigate resistivity, ρ (T), magnetoresistance and Hall effect in p-type CuZnGeS single crystals in pulsed magnetic fields up to 20 T.

Structure of Composite Based on Polyheteroarylene Matrix and ZrO₂ Nanostars Investigated by Quantitative Nanomechanical Mapping.

It is known that structure of the interface between inorganic nanoparticles and polymers significantly influences properties of a polymer⁻inorganic composite. At the same time, amount of experimental researches on the structure and properties of material near the inorganic-polymer interface is low. In this work, we report for the first time the investigation of nanomechanical properties and maps of adhesion of material near the inorganic-polymer interface for the polyheteroarylene nanocomposites based on semi-crystalline poly[4,4'-bis (4″-aminophenoxy)diphenyl]imide 1,3-bis (3',4-dicarboxyphenoxy) benzene, modified by ZrO₂ nanostars.

Young's Modulus of Wurtzite and Zinc Blende InP Nanowires.

The Young's modulus of thin conical InP nanowires with either wurtzite or mixed "zinc blende/wurtzite" structures was measured. It has been shown that the value of Young's modulus obtained for wurtzite InP nanowires (E = 130 ± 30 GPa) was similar to the theoretically predicted value for the wurtzite InP material (E = 120 ± 10 GPa). The Young's modulus of mixed "zinc blende/wurtzite" InP nanowires (E = 65 ± 10 GPa) appeared to be 40% less than the theoretically predicted value for the zinc blende InP material (E = 110 GPa).

Structure and Transport Properties of Mixed-Matrix Membranes Based on Polyimides with ZrO₂ Nanostars.

Mixed-matrix membranes based on amorphous and semi-crystalline polyimides with zirconium dioxide (ZrO₂) nanostars were synthesized. Amorphous poly(4,4'-oxydiphenylenepyromellitimide) and semi-crystalline polyimide prepared from 1,4-bis(4-aminophenoxy)benzene and 4,4'-oxydiphthalic anhydride were used. The effect of ZrO₂ nanostars on the structure and morphology of nanocomposite membranes was studied by wide-angle X-ray scattering, scanning electron microscopy, atomic force microscopy, and contact angle measurements.