Preparation of Reactive Indicator Papers Based on Silver-Containing Nanocomposites for the Analysis of Chloride Ions.

In recent decades, metal-containing nanocomposites have attracted considerable attention from researchers. In this work, for the first time, a detailed analysis of the preparation of reactive indicator papers (RIPs) based on silver-containing nanocomposites derived from silver fumarate was carried out. Thermolysis products are silver-containing nanocomposites containing silver nanoparticles uniformly distributed in a stabilizing carbon matrix. The study of the optical properties of silver-containing nanocomposites made it possible to outline the prospects for their application in chemical analysis. RIPs were made by impregnating a cellulose carrier with synthesized silver fumarate-derived nanocomposites, which change their color when interacting with chlorine vapor. This made it possible to propose a method for the determination of chloride ions with preliminary oxidation to molecular chlorine, which is then separated from the solution by gas extraction. The subsequent detection of the active zone of RIPs using colorimetry makes it possible to identify mathematical dependences of color coordinates on the concentration of chloride ions. The red (R) color coordinate in the RGB (red-green-blue) system was chosen as the most sensitive and promising analytical signal. Calibration plots of exponential and linear form and their equations are presented. The limit of detection is 0.036 mg/L, the limits of quantification are 0.15-2.4 mg/L, and the time of a single determination is 25 min. The prospects of the developed technique have been successfully shown in the example of the analysis of the natural waters of the Don River, pharmaceuticals, and food products.

New Self-Healing Metallosupramolecular Copolymers with a Complex of Cobalt Acrylate and 4'-Phenyl-2,2':6',2″-terpyridine.

Currently, the chemistry of self-healing polymers is aimed not only at obtaining materials with high self-healing efficiency, but also at improving their mechanical performance. This paper reports on a successful attempt to obtain self-healing copolymers films of acrylic acid, acrylamide and a new metal-containing complex of cobalt acrylate with a 4'-phenyl-2,2':6',2″-terpyridine ligand. Samples of the formed copolymer films were characterized by ATR/FT-IR and UV-vis spectroscopy, elemental analysis, DSC and TGA, SAXS, WAXS and XRD studies. The incorporation of the metal-containing complex directly into the polymer chain results in an excellent tensile strength (122 MPa) and modulus of elasticity (4.3 GPa) of the obtained films. The resulting copolymers demonstrated self-healing properties both at acidic pH (assisted by HCl healing) with effective preservation of mechanical properties, and autonomously in a humid atmosphere at room temperature without the use of initiators. At the same time, with a decrease in the content of acrylamide, a decrease in the reducing properties was observed, possibly due to an insufficient amount of amide groups to form hydrogen bonds through the interface with terminal carboxyl groups, as well as a decrease in the stability of complexes in samples with a high content of acrylic acid.

Functionalized Magnetite Nanoparticles: Characterization, Bioeffects, and Role of Reactive Oxygen Species in Unicellular and Enzymatic Systems.

The current study evaluates the role of reactive oxygen species (ROS) in bioeffects of magnetite nanoparticles (MNPs), such as bare (Fe3O4), humic acids (Fe3O4-HA), and 3-aminopropyltriethoxysilane (Fe3O4-APTES) modified MNPs. Mössbauer spectroscopy was used to identify the local surrounding for Fe atom/ions and the depth of modification for MNPs. It was found that the Fe3O4-HA MNPs contain the smallest, whereas the Fe3O4-APTES MNPs contain the largest amount of Fe2+ ions. Bioluminescent cellular and enzymatic assays were applied to monitor the toxicity and anti-(pro-)oxidant activity of MNPs. The contents of ROS were determined by a chemiluminescence luminol assay evaluating the correlations with toxicity/anti-(pro-)oxidant coefficients. Toxic effects of modified MNPs were found at higher concentrations (>10−2 g/L); they were related to ROS storage in bacterial suspensions. MNPs stimulated ROS production by the bacteria in a wide concentration range (10−15−1 g/L). Under the conditions of model oxidative stress and higher concentrations of MNPs (>10−4 g/L), the bacterial bioassay revealed prooxidant activity of all three MNP types, with corresponding decay of ROS content. Bioluminescence enzymatic assay did not show any sensitivity to MNPs, with negligible change in ROS content. The results clearly indicate that cell-membrane processes are responsible for the bioeffects and bacterial ROS generation, confirming the ferroptosis phenomenon based on iron-initiated cell-membrane lipid peroxidation.

Silver Itaconate as Single-Source Precursor of Nanocomposites for the Analysis of Chloride Ions.

At present, conjugated thermolysis of metal-containing monomers is widely used as single-source precursors to obtain new metal- and metal oxide-containing nanocomposites. In this study, a detailed analysis of the main stages of conjugated thermolysis of silver itaconate was carried out. The obtained nanocomposites containing silver nanoparticles are evenly distributed in a stabilizing carbon matrix. The structural characteristics and properties of the resulting nanomaterials were studied using X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDS). We have developed a method of test analysis of chlorides using paper modified with the obtained silver-containing nanocomposites. The analysis technique is based on the in situ conversion of chlorides to molecular chlorine, its dynamic release, and colorimetric detection using NP-modified paper test strips. A simple installation device is described that allows this combination to be realized. The proposed approach seems promising for nanoparticle-based determinations of other analytes that can be converted into volatile derivatives.

Self-Healing of Polymers and Polymer Composites.

This review is devoted to the description of methods for the self-healing of polymers, polymer composites, and coatings. The self-healing of damages that occur during the operation of the corresponding structures makes it possible to extend the service life of the latter, and in this case, the problem of saving non-renewable resources is simultaneously solved. Two strategies are considered: (a) creating reversible crosslinks in the thermoplastic and (b) introducing a healing agent into cracks. Bond exchange reactions in network polymers (a) proceed as a dissociative process, in which crosslinks are split into their constituent reactive fragments with subsequent regeneration, or as an associative process, the limiting stage of which is the interaction of the reactive end group and the crosslink. The latter process is implemented in vitrimers. Strategy (b) is associated with the use of containers (hollow glass fibers, capsules, microvessels) that burst under the action of a crack. Particular attention is paid to self-healing processes in metallopolymer systems.

Preparation of FeCo/C-N and FeNi/C-N Nanocomposites from Acrylamide Co-Crystallizates and Their Use as Lubricant Additives.

FeCo and FeNi nanoalloy particles encapsulated in a nitrogen-doped carbonized shell (FeCo/C-N and FeNi/C-N) were synthesized by thermolysis at 400 °C of polyacrylamide complexes after frontal polymerization of co-crystallizate of Fe and Co or Ni nitrates and acrylamide. During the thermolysis of polyacrylamide complexes in a self-generated atmosphere, Co(II) or Ni(II) and Fe(III) cations are reduced to form FeCo and FeNi nanoalloy particles, while polyacrylamide simultaneously forms a nitrogen-doped carbon shell layer. This unique architecture provides high chemical and thermal stability of the resulting nanocomposites. The average crystallite size of FeCo and FeNi nanoparticles is 10 and 12 nm, respectively. The nanocomposites were studied by X-ray diffraction, atomic force microscopy, scanning electron microscopy, and high-resolution transmission electron microscopy. The nanocomposites have been tested as antifriction and antiwear additives in lubricating oils. The optimal concentrations of nanoparticles were determined, at which the antifriction and antiwear properties of the lubricant manifest themselves in the best possible way.

Novel Self-Healing Metallocopolymers with Pendent 4-Phenyl-2,2':6',2″-terpyridine Ligand: Kinetic Studies and Mechanical Properties.

We report here our successful attempt to obtain self-healing supramolecular hydrogels with new metal-containing monomers (MCMs) with pendent 4-phenyl-2,2':6',2″-terpyridine metal complexes as reversible moieties by free radical copolymerization of MCMs with vinyl monomers, such as acrylic acid and acrylamide. The resulting metal-polymer hydrogels demonstrate a developed system of hydrogen, coordination and electron-complementary π-π stacking interactions, which play a critical role in achieving self-healing. Kinetic data show that the addition of a third metal-containing comonomer to the system decreases the initial polymerization rate, which is due to the specific effect of the metal group located in close proximity of the active center on the growth of radicals.

2-D self-healable polyaniline-polypyrrole nanoflakes based triboelectric nanogenerator for self-powered solar light photo detector with DFT study.

This work demonstrates an easy and cost-effective synthesis of PANI-PPY conducting nanoflakes (NFs) with a self-healing capability. Scanning electron microscopic (SEM) analysis shows the minimum width of NFs as 30 nm, while HRTEM analysis confirms the shape, size, and semi-crystalline nature of the polymer. These PANI-PPY NFs were used to fabricate a contact separation mode triboelectric nanogenerator (TENG) based self-powered photosensor which gave the maximum output voltage (149 V), maximum output current (16 µA), current density 0.56 µAcm-2, and power density 83.56 µWcm-2. Detailed literature survey shows the comparative study of PANI-PPY NF's with other photo-sensing materials. This literature review highlights the tremendous ability of PANI-PPY to self-restore and ultra-fast self-powering nature. This work also demonstrates a very easy and cost-effective method to develop polymeric nanomaterials via temperature-assisted polymerization, which need only a stirrer with a hot plate. Theoretical analysis (DFT calculations using Gaussian 09 and Gauss view 05) shows a consistent increase in stability when the number of molecules in the polymer chains analyzed was increased. The developed self-healing triboelectric nanogenerators exhibited stable performance before and after healing.

Basic Approaches to the Design of Intrinsic Self-Healing Polymers for Triboelectric Nanogenerators.

Triboelectric nanogenerators (TENGs) as a revolutionary system for harvesting mechanical energy have demonstrated high vitality and great advantage, which open up great prospects for their application in various areas of the society of the future. The past few years have seen exponential growth in many new classes of self-healing polymers (SHPs) for TENGs. This review presents and evaluates the SHP range for TENGs, and also attempts to assess the impact of modern polymer chemistry on the development of advanced materials for TENGs. Among the most widely used SHPs for TENGs, the analysis of non-covalent (hydrogen bond, metal-ligand bond), covalent (imine bond, disulfide bond, borate bond) and multiple bond-based SHPs in TENGs has been performed. Particular attention is paid to the use of SHPs with shape memory as components of TENGs. Finally, the problems and prospects for the development of SHPs for TENGs are outlined.

Effects of Modified Magnetite Nanoparticles on Bacterial Cells and Enzyme Reactions.

Current paper presents biological effects of magnetite nanoparticles (MNPs). "Relations of MNP' characteristics (zeta-potential and hydrodynamic diameters) with effects on bacteria and their enzymatic reactions were the main focus.". Photobacterium phosphoreum and bacterial enzymatic reactions were chosen as bioassays. Three types of MNPs were under study: bare Fe3O4, Fe3O4 modified with 3-aminopropyltriethoxysilane (Fe3O4/APTES), and humic acids (Fe3O4/HA). Effects of the MNPs were studied at a low concentration range (< 2 mg/L) and attributed to availability and oxidative activity of Fe3+, high negative surface charge, and low hydrodynamic diameter of Fe3O4/HA, as well as higher Fe3+ content in suspensions of Fe3O4/HA. Low-concentration suspensions of bare Fe3O4 provided inhibitory effects in both bacterial and enzymatic bioassays, whereas the MNPs with modified surface (Fe3O4/APTES and Fe3O4/HA) did not affect the enzymatic activity. Under oxidative stress (i.e., in the solutions of model oxidizer, 1,4-benzoquinone), MNPs did not reveal antioxidant activity, moreover, Fe3O4/HA demonstrated additional inhibitory activity. The study contributes to the deeper understanding of a role of humic substances and silica in biogeochemical cycling of iron. Bioluminescence assays, cellular and enzymatic, can serve as convenient tools to evaluate bioavailability of Fe3+ in natural dispersions of iron-containing nanoparticles, e.g., magnetite, ferrihydrite, etc.

Synthesis of Copper(II) Trimesinate Coordination Polymer and Its Use as a Sorbent for Organic Dyes and a Precursor for Nanostructured Material.

Several important synthesis pathways for metal-organic frameworks (MOFs) were applied to determine how the synthesis methods and conditions affect the structure and adsorption capacity of the resulting samples. In the present work, three different synthesis routes were used to obtain copper trimesinate coordination polymer: Slow evaporation (A), solvothermal synthesis using a polyethylene glycol (PEG-1500) modulator (B), and green synthesis in water (C). This MOF was characterized by elemental analysis, infrared spectrometry, X-ray diffraction, scanning electron microscopy, thermogravimetry and volumetric nitrogen adsorption/desorption. The samples have permanent porosity and a microporous structure with a large surface area corresponding to the adsorption type I. The obtained MOF was tested as a sorbent to remove organic dyes methylene blue (МВ), Congo red (CR) and methyl violet (MV) as examples. Dye adsorption followed pseudo-first-order kinetics. The equilibrium data were fitted to the Langmuir and Freundlich isotherm models, and the isotherm constants were determined. Thermodynamic parameters, such as changes in the free energy of adsorption (ΔG0), enthalpy (ΔH0), and entropy (ΔS0), were calculated. Thermolysis of copper trimesinate leads to the formation of carbon materials Cu@C with a high purity.

Flow-Through Catalytic Reactors Based on Metal Nanoparticles Immobilized within Porous Polymeric Gels and Surfaces/Hollows of Polymeric Membranes.

State-of-the-art of flow-through catalytic reactors based on metal nanoparticles immobilized within the pores of nano-, micro- and macrosized polymeric gels and in the surface or hollow of polymeric membranes is discussed in this mini-review. The unique advantages of continuous flow-through nanocatalysis over the traditional batch-type analog are high activity, selectivity, productivity, recyclability, continuous operation, and purity of reaction products etc. The methods of fabrication of polymeric carriers and immobilization technique for metal nanoparticles on the surface of porous or hollow structures are considered. Several catalytic model reactions comprising of hydrolysis, decomposition, hydrogenation, oxidation, Suzuki coupling and enzymatic reactions in the flow system are exemplified. Realization of "on-off" switching mechanism for regulation of the rate of catalytic process through controlling the mass transfers of reactants in liquid media with the help of stimuli-responsive polymers is demonstrated. Comparative analysis of the efficiency of different flow-through catalytic reactors for various reactions is also surveyed.

Self-healing and shape memory metallopolymers: state-of-the-art and future perspectives.

Metallopolymers (MPs) or metal-containing polymers have shown great potential as self-healing and shape memory materials due to their unique characteristics, including universal architectures, composition, properties and surface chemistry. Over the past few decades, the exponential growth of many new classes of MPs that deal with these issues has been demonstrated. This review presents and assesses the latest achievements and problems associated with the use of MPs as self-healing and shape memory materials. Among the most widely used MPs with self-healing properties, metal complexes based on polymers containing phenol, carboxylic acid, pyridine, azole, histidine and urethane donor fragments are identified. Particular attention is paid to the principles of action of the shape memory MPs. Of considerable interest is the use of MPs as functional materials for sensors, soft electronic devices, transistors, conductors, nanogenerators, bone tissue engineering, etc. Finally, the problems and future prospects of MPs with self-healing and shape memory properties are outlined. This review also analyzes articles published over the past five years.

Recent advances in metallopolymer-based drug delivery systems.

Metallopolymers (MPs) or metal-containing polymers have shown great potential as new drug delivery systems (DDSs) due to their unique properties, including universal architectures, composition, properties and surface chemistry. Over the past few decades, the exponential growth of many new classes of MPs that deal with these issues has been demonstrated. This review presents and assesses the recent advances and challenges associated with using MPs as DDSs. Among the most widely used MPs for these purposes, metal complexes based on synthetic and natural polymers, coordination polymers, metal-organic frameworks, and metallodendrimers are distinguished. Particular attention is paid to the stimulus- and multistimuli-responsive metallopolymer-based DDSs. Of considerable interest is the use of MPs for combination therapy and multimodal systems. Finally, the problems and future prospects of using metallopolymer-based DDSs are outlined. The bibliography includes articles published over the past five years.

Synthetic methodologies and spatial organization of metal chelate dendrimers and star and hyperbranched polymers.

The synthetic methodologies, physico-chemical peculiarities, properties, and structure of metal chelate dendrimers and star and hyperbranched polymers are considered. These compounds are subdivided into molecular, intracomplex, and macrocyclic types which in turn are classified depending on the nature of the donor atoms (N,N-, N,O-, N,S-, O,O-, O,S-, S,S-, P,P-chelates, etc.). Special attention is paid to the features of the preparation of metal chelate star polymers by "arm-first", "core-first" and click-to-chelate approaches. The main data on the synthesis, spatial structure and properties of the metal chelate hyperbranched polymers are summarized. The basic concepts and synthetic strategies leading to the different types of supramolecular metal chelate dendrimers are analyzed. The problems and future prospects of metal chelate dendrimers and star and hyperbranched polymers are outlined. The bibliography includes papers published after 2010.