Reduction Of Copper Ions Research Articles

In-situ copper ion reduction and micro encapsulation of wood-based composite PCM with effective anisotropic thermal conductivity and energy storage

This work develops metallic wood-based phase change materials (MWPCM) with high-performance anisotropic thermal conductivity by impregnating wood with phase change microcapsules and subsequent in situ chemical deposition of copper inside the wood cell lumen. Phase change material (PCM) is encapsulated by polymer to form phase change microcapsules, which solve the leakage problem effectively. Benefited with the well-aligned and hierarchical porous structure of wood, phase change microcapsules coated with copper layer are orderly confined inside wood vessels and fibers, developing a continuous and anisotropic heat transfer network along the highly oriented transport tissues of wood. The morphology, chemical structure and crystallization of microcapsules and MWPCM are investigated using scanning electronic microscope (SEM), flourier transformation infrared spectroscopy (FTIR) and X-ray diffractometer (XRD), and the thermal storage capacity, thermal stability and thermal conductivity of the developed PCM composites are examined using differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA) and laser flash diffusivity apparatus (LFA) respectively. The results show that PCM capsules were effectively accommodated in orderly porous wood as a carrier; the radial and longitudinal thermal conductivity of MWPCM reached 0.37 W/(m*K) and 0.53 W/(m*K), which increased by 362% and 211% compared to pure wood, respectively. The anisotropic thermal conductivity of MWPCM enabled an efficient heat transfer along the longitudinal direction and reduced the heat loss in the transverse direction. MWPCM exhibited good thermal energy storage capacity (92.9 J/g and 94.6 J/g) and suitable phase change temperature (11.4 °C and 29.4 °C) for indoor thermal energy management. MWPCM also displayed outstanding shape-stability, excellent thermal stability and temperature regulation, which has a great potential for building energy collecting, storage and management.

Biogenic synthesis of ferrous(III) oxide and Fe3O4/SiO2 using Chlorella sp. and its adsorption properties of water contaminated with copper(II) ions

ABSTRACT. Magnetic nanoparticles (MNPs) are gaining popularity because of their small size allowing for research into the fundamentals of magnetism. In wastewater treatment, adsorption methods commonly remove heavy metals, but copper (Cu+2) ion removal using magnetic nanoparticles (NPs) has not been investigated. In this study two different modes were used to determine maximum adsorption capacity to remove copper(II). The nanoparticles containing the Fe3O4 with Chlorella, core-shell Fe3O4/SiO2 with Chlorella sp. synthesized and characterized by Fourier transform infrared (FT-IR) analysis, the morphology observed by scanning electron microscope (SEM), crystalline structure, and grain size provided by energy dispersive X-ray (EDX) and X-ray diffraction (XRD). Copper(II) ion removal showed in both modes. The maximum copper(II) ion reduction percent was obtained by nanoparticles containing core-shell Fe3O4/Chlorella 80.3%, Fe3O4/SiO2 with Chlorella sp. (86.9%) the result showed maximum removal using Fe3O4/SiO2 with Chlorella sp. due to increase of surface area. The results indicate that the adsorption using magnetic nanoparticles with Chlorella sp. enhances the cell surface and provides easy access to the separation for both preparation and recapture.
 
 KEY WORDS: Copper(II) ion, Magnetic nanoparticles, Chlorella sp., SiO2 core-shell, Adsorption capacity percent
 Bull. Chem. Soc. Ethiop. 2022, 36(3), 585-596. 
 DOI: https://dx.doi.org/10.4314/bcse.v36i3.8

Anti-aging and Antioxidant Activities of Ethanol and Three-phase Partitioned Extracts of Inula viscosa

Inula viscosa is a plant commonly used to treat inflammation, germicide, expectorant, cough reducer, diuretic, anemia, and cancer. In addition to its medicinal effect, this plant has been preferred because it is thought to be a free radical scavenger and anti-aging effect due to its phenolic compounds. The aim of the study was to determine whether the plant has antioxidant and anti-aging potential. The plant was extracted with both the traditional solvent extraction method with ethanol and the novel three-phase partitioned (TPP) system, and the two methods were compared. The methods of DPPH free radical scavenging, ABTS cation radical scavenging, superoxide anion radical scavenging, and reduction of copper and iron ions were used to determine the antioxidant effects of the obtained extracts. In addition, elastase enzyme inhibition was studied to investigate the anti-aging potential. TPP method (23.9% yield) was performed at a higher yield than the solvent extraction (8.99% yield). The ethanolic extract and TPP extract of plant inhibited the DPPH free radical with IC50=0.27 µg/mL and IC50=0.026 µg/mL, and ABTS cation radical with IC50=0.28 µg/mL and IC50=0.13 µg/mL, and superoxide anion radical with IC50=3.53 µg/mL and IC50=2.43 µg/mL, respectively. According to the elastase inhibition results, IC50=3.11 µg/mL for ethanol extract and IC50=3.05 µg/mL for TPP extract were obtained. Both extracts of I. viscosa showed antioxidant and anti-aging effects at levels close to the standards. In addition, according to the results, TPP extract was found to be more effective than ethanol extract.

Electrodeposited Ni-Cu Coatings with Hierarchical Surface Morphology

In recent years, Ni-Cu alloy coatings obtained by electrolytic deposition have received increasing interest, because of their good anti-corrosive, mechanical, magnetic, electrical, and decorative properties. Further applications of these coatings for electrode materials and catalysts may be possible by developing hierarchical surface morphology, and thus a combination of high surface roughness, high microhardness, and good corrosion resistance. In the present work, four types of Ni-Cu alloy coatings were deposited in a single-step process from electrolytic baths with Cu2+:Ni2+ concentrations equal to 1:30, 1:20, 1:15, and 1:10 using deposition current densities of 2 A/dm2 and 4 A/dm2. The surface morphology of the coatings was characterized using a scanning electron microscope and an optical profilometer. The coatings exhibited a nodular morphology, which with the change of the Cu2+:Ni2 ratio and the current parameters changed from smooth and compact to rougher with regularly spaced nodular microprotrusions. Thus, a hierarchical surface morphology was obtained. Transmission electron microscopy investigations revealed that the fine-grained microstructure of the coatings consisted of the γ solid solution, as well as the metastable intermetallic L10 NiCu phase. The differences in the Cu concentration at the cross-sections demonstrated by quantitative microanalysis of the chemical composition indicated a dendritic growth of the coatings and a preferential reduction of copper ions over nickel ions. The coatings were also characterized by a microhardness greater than 3.71 GPa and good electrochemical corrosion resistance in chloride media. Coatings with hierarchical morphology and high surface roughness showed a higher corrosion current. The study provides a new method for electrodeposition hierarchical Ni-Cu coatings under specific chemical compositions of the electrolytic bath and current conditions, characterized by a combination of promising properties for electrode and catalytic applications.Graphical

Biosynthesis of copper oxide nanoparticles using Rubia cordifolia bark extract: characterization, antibacterial, antioxidant, larvicidal and photocatalytic activities.

Rubia cordifolia represents the pivotal plant resource belonging to traditional Chinese medicine and Indian Ayurveda. The present study aims to synthesize biocompatible copper oxide nanoparticles (CuONPs) using R. cordifolia bark extracts, characterize the incumbent chemical transitions, and explore their biomedical and environmental applications. The absorbance peak between 250 and 300nm clearly demonstrates the formation of CuONPs in the UV-visible spectrum. Fourier transform infrared spectroscopy results showed the presence of functional groups essential for copper ion reduction. Field emission scanning electron microscopy (FE-SEM) and dynamic light scattering analysis revealed that the CuONPs are spherical-shaped with a mean particle size of 50.72nm. Additionally, the zeta potential demonstrates its robustness at 11.2mV. X-ray diffraction pattern showed mixed phases (Cu, Cu2O, and CuO) of cubic monoclinic crystalline nature. CuONPs exhibited noticeable antibacterial activity against Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus and Bacillus cereus) pathogenic bacteria. Bacterial cell damages were affirmed through FE-SEM imaging when treated with CuONPs. Further, CuONPs demonstrated considerable antioxidant activities by quenching free radicals such as DPPH (60.75%), ABTs (70.88%), nitric oxide (65.48%) and reducing power (71.44%) in a dose-dependent way. CuONPs showed significant larvicidal activity against Aedes aegypti (65 ± 8.66%), Anopheles stephensi (80 ± 13.69%), and Culex quinquefasciatus (72 ± 13.04%) mosquito larvae. The photocatalytic activity of the CuONPs demonstrates the methylene blue (81.84%) and crystal violet (64.0%) dye degradation potentials, indicating the environmental bioremediation efficacy. Hence the present study is the first report in accounting for the versatile applications of the phyto-CuONPs. Moreover, the green synthesis of CuONPS has future applications in designing the drug for life-threatening diseases and various environmental issues.

Obtainment and Characterization of Metal-Coated Polyethylene Granules as a Basis for the Development of Heat Storage Systems.

The research studied the feasibility of using copper-coated polyethylene granules as a basis for creating efficient heat storage systems. A technology for imparting catalytic properties to a polymer surface by the joint processing of polymer granules and an activator metal in a ball mill with their subsequent metallization in a chemical reducing solution is proposed. The efficiency of copper-coating a polyethylene surface is shown to be largely determined by the activation stage and the assumption regarding the mechanism of interaction of the activator metal with the polymer surface is made. To obtain different amounts of metal on the polyethylene granules, it is proposed that the method of remetallization is used. It was established that the rate of copper ion reduction depends on the number of previous coatings and is determined by the area of interaction of the metal-coated granules with the chemical reducing solution. The obtained metal-coated polyethylene granules were characterized in terms of the viability of using it as a phase transition material for a heat storage system. Using the developed installation that simulates the heat accumulator operation, it was shown that the efficiency of using metal-coated polyethylene granules to create heat storage systems is higher. The copper coating deposited on the polyethylene granules was studied using scanning electron microscopy and X-ray diffraction analysis.

Copper depletion combined with photothermal therapy suppresses breast cancer

Robust nanoparticles of a multifunctional molecule (PY-TBDP) have been prepared, which could achieve enhanced tumor inhibition effect by the reduction of copper ions in tumor cells and the mild photothermal effect.

Degradation of Toxic Dye Using Phytomediated Copper Nanoparticles and Its Free-Radical Scavenging Potential and Antimicrobial Activity against Environmental Pathogens.

The present investigation deals with the green synthesis of copper nanoparticles in an ecofriendly manner using leaf extract of Andrographis paniculata. Green-synthesized copper nanoparticles were studied for their antibacterial, antioxidant, and catalytic activity. The leaves were powdered and extracted with water and added to copper sulphate solution. The reduction of copper ions to nanoparticles was preliminarily identified by the color change of the reaction mixture. The synthesized nanoparticle was characterized by using a UV-Vis Spectrophotometer at a different wavelength with different time intervals. Functional groups available on the surface of the nanoparticle were identified by Fourier transform infrared spectroscopy (FTIR). Surface roughness was characterized by atomic force microscopy (AFM). X-ray diffraction (XRD) analysis showed six distinct intense peaks indicating the crystalline nature of synthesized copper nanoparticles (CuNPs). A scanning electron microscope (SEM) demonstrated polydispersed nanoparticles formed in the reaction process. The antibacterial activity of the nanoparticles was evaluated by an agar well diffusion assay against pathogenic bacteria. The antioxidant activity showed the excellent reduction of DPPH free radicals by nanoparticles. These results confirmed that copper nanoparticles serve as an alternative therapeutic agent over conventional drugs. Moreover, copper nanoparticles were also used to study the effect on the dye degradation process of methyl red and eosin dyes. Copper nanoparticles effectively remove the dyes with high efficiency up to 92% and 95% of methyl red and eosin dye, respectively.

How a family of nanostructured amphiphilic block copolymers synthesized by RAFT-PISA take advantage of thiol groups to direct the in situ assembly of high luminescent CuNCs within their thermo-responsive core

• Multithiolated block copolymer nanoparticles (P-NPs) were synthesized by RAFT-PISA. • Monodisperse P-NPs with tunable size are formed under uncontrolled RAFT polymerization. • P-NPs with thermo-responsive core and hydrophilic shell exhibit high water stability. • Thiolated P-NPs serve as template for in situ assembly of luminescent CuNCs in water. • Fluorescent nanohybrids exhibit pH/thermo-response, photostability and oxidation resistance. The development of fluorescent water stable copper nanoclusters (CuNCs) deserves the scientific interest due to their outstanding properties and low-cost. These fluorescent CuNCs can be synthesized using natural or synthetic polymers with thiol groups. Herein, for the first time, we propose the use of novel amphiphilic block copolymer nano-objects, synthesized by polymerization induced self-assembly (PISA) via reversible-addition fragmentation chain transfer (RAFT), as templates for the synthesis and water stabilization of CuNCs. The polymeric NPs provide water-stability due to the poly(hydroxyethyl acrylate) corona and the thermos-responsive core, based on 2-(2-methoxyethoxy) ethyl methacrylate (MEO 2 MA) and 2-(acetylthio) ethyl methacrylate (AcSEMA) decorated with protected thiol groups, drive the “ in situ ” reduction of copper ions into copper nanocrystals and their assembling in high luminescent nanohybrids in water. In order to optimize the fluorescence properties a methodical study was carried out varying polymers composition and architecture, thiol content and nanoparticle size. All the polymeric nanoparticles synthesized by PISA and decorated with thiol groups induce the formation of luminescent CuNCs in their hydrophobic core. The sizes of the hydrophilic/hydrophobic block, as well as, thiol content are key factors in the emission properties of the CuNC nanohybrids that offer high colloidal stability in water, pH- and thermo-response, significance photostability and strong resistance to oxidation.

Peculiarities of metallization of polyvinyl chloride granules

The results of experimental studies of copper plating of polyvinyl chloride granules in a chemical precipitation solution are presented. The influence of the surface area of polyvinyl chloride granules on the kinetic regularities of copper reduction and the copper content on metallized granules has been studied. It is established that the surface area of polyvinyl chloride granules has a significant effect on the rate of reduction of copper ions and does not affect the amount of reduced copper. The thickness of the layer of the obtained copper shell on polyvinyl chloride granules of different sizes depending on the metal content is calculated.

An operando ORP-EIS study of the copper reduction reaction supported by thiourea and chlorides as electrorefining additives

Additives are used in metal electroreduction processes to obtain a smooth and optimal metal deposit. However, the mechanism with which these additives influence the metal deposition is poorly understood. Operando odd random phase electrochemical impedance spectroscopy (ORP-EIS) experiments have been performed to study the effect of a chloride-thiourea additive mixture on the reduction of copper ions in a sulfuric acid solution. This additive mixture is crucial in the copper electrorefining process. An optimal experimental design and a well-founded methodology is applied to study this complex additive mixture. The ORP-EIS data is studied to analyze non-stationarities and non-linearities and the time-varying impedance is resolved when necessary. Two equivalent circuits are proposed to model the impedance data and the model parameters are linked to physical processes in the system. The use of the time-varying impedance when studying thiourea in a plating process and the use of distributed circuit elements in the EIS model is discussed.

Mussaenda frondosa L. mediated facile green synthesis of Copper oxide nanoparticles – Characterization, photocatalytic and their biological investigations

Green synthesis of Copper oxide nanoparticles (CuO-NPs) was achieved by using different parts of Mussaenda frondosa plant such as leaf, stem and leaf derived callus. Biofabricated CuO-NPs were characterized using Powder X- ray diffraction (XRD), Ultraviolet–visible spectroscopy (UV–Vis), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy Dispersive Spectroscopy (EDS), Fourier Transform Infrared spectroscopy (FTIR) and Dynamic light scattering (DLS) analysis. The XRD spectra confirmed the formation of pure monoclinical crystalline nature of CuO-NPs with an average grain size in the range of 2–10 nm. An extremely strong Surface Plasmon Resonance (SPR) between 300 and 400 nm distinctly reveals the synthesis of CuO-NPs. SEM and TEM analysis revealed the formation of spherical shaped agglomerated structures amidst large surface area. EDS spectra proved the existence of copper and oxygen elements in nanomaterials. FTIR spectra explained the possible bioactive molecules liable for the reduction of copper ions. DLS analysis and Zeta potential values validated the stability of CuO-NPs. The pore width distribution by the BJH plot indicates the mixture of meso as well as macropores with large surface area confirmed by BET analysis. Furthermore, the biofabricated NPs were investigated for photocatalytic and biological applications. CuO-NPs were found to exhibit potent DPPH radical scavenging activity. The cytotoxicity study was evaluated by MTT assay against Human lung cancer cell line (A549) and affirms the potent anticancer activity of CuO-NPs. The results of photocatalytic activity of methylene blue dye under UV- light depict 97.36% degradation at 140 min of illumination. Our studies illustrate facile green synthesis of CuO-NPs and found to possess significant biomedical and industrial applications.

Study of metal-polymer copper nanocomposites using the method of UV spectroscopy

New polymer copper-containing nanocomposites based on poly-N-vinylimidazole were obtained. The formation of nanocomposites was carried out using the method of chemical reduction of copper ions from a solution of copper acetate with ascorbic acid in an aqueous medium in the presence of a polymer. Nanocomposites were prepared at the polymer:Cu (II) molar ratio of 10:1 and 5:1. The reduction reaction yielded powder nanocomposites of a red-brown colour and having a metallic shine. It was found that the content of copper in the obtained nanocomposites depends on the initial molar ratio of the stabilising poly-N-vinylimidazole and Cu (II), reaching 5.9% and 11.7%. The formation of nanosized copper particles was investigated and confirmed by UV spectroscopy. The optical spectra of aqueous solutions of the obtained copper-containing nanocomposites contained maxima at 537–541 and 646–651 nm, which confirmed the formation of ultradispersed copper in the nanosized state. The obtained copper-containing nanocomposites based on poly-N-vinylimidazole are promising materials for use in medicine and catalysis, as well as in optical, sensor and electronic devices.

The copper ion reduction and oxidation cycle during the cathodic process of gold thiosulfate leaching

AbstractThe copper ion reduction and oxidation cycle during the cathodic process of gold thiosulfate leaching was studied using a rotating disc electrode and cyclic voltammetry, and the dynamic characteristics of the system were discussed. In a copper ammonium solution, the redox reactions of were reversible and controlled by substance diffusion. The rotating disc electrode and the reduction method with a constant potential showed that the generated during the reduction process was easily oxidized by O2 to . In the copper ammonium and thiosulfate system, the reversibility of the redox reactions of became worse, and the reduction process was still controlled by material diffusion and had a higher diffusion coefficient than that in the copper ammonium solution. However, under this condition, the oxidation reaction of the generated Cu(I) species was complicated. The reduction method with a constant potential showed that the rate‐determining step for the cathodic process was the oxidation step of the Cu(I) species. In addition, some amount of Cu(I) species in solution could not be oxidized in time under the experimental conditions. This part of Cu(I) species may be included during the oxidation decomposition of thiosulfate, thus affecting the dissolution of gold.

Adsorption of Copper Ions (Cu++) in Aqueous Solution Using Activated Carbon and Biosorbent from Indian Jujube (Ziziphus mauritiana) Seed Hulls

The present work aimed at mitigating the level of copper ions (Cu++) by adsorption in aqueous solution using activated carbon powder (AC) and biosorbent (BS) from the Indian jujube seed hulls. The AC and BS were prepared from the Indian jujube seed hulls and characterized using standard procedures. In addition, the adsorption effects of Indian jujube seed hulls through the AC and BS were carried out using jar test experiment (batch mode) at different pH (1, 2, 3, and 4), ionic strengths (100-600 mg/L) and stirring speed (120rpm). Therefore, it was found that the adsorption time at equilibrium were 10 and 5 minutes respectively for the AC and the BS. Furthermore, it was found that the reduction of copper ions were 99.40% and 73.08% for aqueous solutions of 100 ppm and 500 ppm respectively at the equilibrium state. It was also revealed that when the mass of the AC or the BS increases, the quantities of ions adsorbed per gram decrease. The maximum pH of adsorption for the AC was found to be pH=1, while it was found to be pH=4 for the BS. The Freundlich model indicated that the adsorption of copper ions by the Indian jujube is linear while the Temkin and Dubinin-Kagana-Radushkevich models described the adsorption as a physical reaction. It was finally observed that the adsorption of copper ions by the AC and the BS from Indian jujube seed hulls influenced by the addition of some concentration of NaCl.

Effect of thiourea on electrocrystallization of Cu–Sn alloys from sulphate electrolytes

In this work, the effect of thiourea on the initial stages of the Cu–Sn electrodeposition in the potential range of the underpotential deposition (UPD) of tin from the sulphate electrolyte was studied by linear sweep voltammetry. The mechanism of Cu–Sn alloy nucleation and growth was proposed based on the results of chronoamperometry, chronopotentiometry, and scanning electron microscopy. Thiourea in the concentrations of 0.001–0.010 g/L showed a significant inhibitory effect on the reduction of copper ions. Analysis of the current-time dependencies revealed that Cu–Sn deposition in the UPD region of tin from thiourea-containing solutions proceeds through 3D diffusion-controlled growth of copper clusters. The nucleation type and the main nucleation parameters were calculated based on the Scharifker and Hills theoretical model. Galvanostatic experiments proved that the UPD of tin occurs on the surface of initially formed copper clusters. Surface characterization of Cu–Sn coatings deposited in the presence of thiourea showed a good correlation with electrochemical experiments.

Influence of Organic Dye Ligands on the Photocatalytic Reduction of Copper Ions in Aqueous Solution Using UV-Nano TIO2 System

This study investigates the influence of some organic dyes on the photocatalytic reduction of Cu (II) ions in aqueous solution. The dyes of interest were Eosin red, Eriochrome black T, Bromothymol blue and Malachite green. Slurry photoreactor design, with nano-sized titanium dioxide photocatalysts, and illuminated by a 15 W UV light, was utilized. Results showed that the percentage reduction of Cu (II) ions altered from 44.7% (without dye) to 25.7% (with ER), 60.7% (with EBT), 15.2% (with BTB) and 17.8% (with MG) after 60 minutes reaction time at pH 5. This implies that EBT enhanced Cu (II) ions reduction while the other three dyes inhibited the photoreduction process. The kinetic study indicated that the photo-reduction of Cu (II) ions followed the pseudo-first-order kinetics, with the exception of Cu-MG reduction which gave the best correlation values in zeroth-order plot. Statistical analysis was carried out with the ANOVA, Dunnetts post-hoc and Tukeys post-hoc multiple comparison tests. Tukeys post-hoc multiple comparison test was effected to determine the pair of Cu (II) ions with significant difference in mean values while Dunnetts post-hoc was effected to compare the measured values with the initial values. Photoreduction of Cu (II) ions were considered significant at P< 0.05 and 95% confidence interval.

Electrical and microstructure characteristics of SU8–Cu composite thin film fabricated using femtosecond laser direct writing

Through photo-patterning by a femtosecond laser direct writing on a spin-castable composite, this study presents a novel approach for fabricating highly conductive composite microstructures. Composite material was developed using SU8 (glycidyl ether of bisphenol A) and copper precursors, particularly copper (II) nitrate trihydrate and copper (II) chloride dehydrate. Copper was employed as the filler due to its excellent electrical conductivity and cost-effectiveness. The synthesized composite solution was first spin-coated on a substrate, and the dried thin film was then subjected to femtosecond laser direct writing to form pattern microstructures. Femtosecond laser irradiation induced two-photon absorption that led to polymerization of SU8, reduction of copper ions and sintering of copper particles. The resulting surface morphology of microstructures was affected by scanning speed, as low speed subsequently led to heat accumulation and ablation, while the line width was mainly determined by laser power. Electrical resistance decreases with the increase in scanning speed until an optimum scanning speed was achieved. On the other hand, as laser power increased, line width increased, while resistance decreased. Electrical conductivity of 365.5 S/m was achieved, which is a leap of advancement as compared to pure SU8 with conductivity of 10–14 S/m.

Investigation of catalytic and fuel additive applications of copper/copper(I) oxide/copper(II) oxide (Cu/CuO/Cu2O) microspheres synthesized by hydrothermal method using sucrose as template

Role of sucrose in sequential reduction of copper (II) ions is investigated. Copper/copper(I) oxide/copper(II) oxide (Cu/CuO/Cu2O) microspheres are synthesized via hydrothermal method using sucrose as template. Size of microparticles lies in 9–16 μm range. Formation mechanism of spherical architecture is also proposed. Synthesized spheres are used in two major applications: (i) catalyst for degradation of methyl red (MR) and methyl blue (MB) (ii) fuel additive in commercial diesel. The rate constant of degradation of both dyes (MB and MR) is not found equal under similar conditions. Results indicated that increased concentrations of microparticles in diesel significantly affect properties.

Generation of spatially ordered metal–polymer nanostructures in the irradiated dispersions of poly(acrylic acid)–poly(vinylimidazole)–Cu2+ complexes

The generation of metal nanostructures by radiation-induced reduction of copper ions in aqueous dispersions of macromolecular complexes of poly(acrylic acid) and polyvinylimidazolе has been studied in the pH range of 2.3–4.3. It was shown that an effective coordination number of Cu2+ in the complex with polymer units decreased at lower pH, which resulted in dramatic increase of the nanoparticle formation rate. As demonstrated by transmission electron microscopy, using the poly(acrylic acid)–polyvinylimidazolе–Cu2+ complexes as precursors allows one to control the nanoparticle size and promotes assembling of spatially ordered supramolecular structures. As revealed by dynamic light scattering, decreasing the medium pH leads to ripening of the poly(acrylic acid)–polyvinylimidazolе–Cu2+ particles. The obtained results provide an evidence for strong effect of the pH value on the spatial organization of nanoparticles in irradiated suspensions. In the case of less acidic medium (at pH 3), assembling of nanoparticles occurs in flabby interpolymer particles, whereas at lower pH the metal nanoparticles are produced in the templates of the perfect macromolecular nanostructures.