Synthesis Of Copper Nanowires Research Articles

Ethylenediamine Mediated, Environmentally Benign Synthesis of Copper Nanowires and their Catalytic Activity Towards 4‐Nitrophenol Reduction

AbstractDue to their unique characteristics, one‐dimensional copper (Cu) nanowires are being explored for various applications, including optoelectronics, chemical sensing, catalysis, electrocatalysis, etc. Cu is more affordable and accessible than other noble metals, making it a desirable replacement. Cu nanowires are predominantly synthesized using ethylenediamine (EDA) mediated procedure, in which hydrazine is used as a reducing agent. This method does not require high temperatures and produces good‐quality nanowires within an hour. However, the toxicity of hydrazine limits the large‐scale synthesis of wires using this cost‐effective method, inspite of its advantages mentioned above. Hence, this article aimed to replace the toxic hydrazine with environmentally benign ascorbic acid in EDA‐mediated procedures. Such green synthesis using ascorbic acid successfully yielded Cu nanowires. As revealed by TEM analysis, these Cu nanowires evolved from micron‐sized aggregates of ultra‐small particles. Due to the capping action of EDA, nanowires evolved from the micron‐sized aggregates of ultra‐small particles and resulted in particles attached nanowires (at one end of the nanowires) with a clear particle‐wire interface. Environmentally benign synthesized Cu nanowires are examined as catalysts for the remediation of environmental organic pollutant, i. e., 4‐nitrophenol (4‐NP). Towards the reduction of 4‐NP, green synthesized Cu nanowires have shown on‐par activity with earlier reported catalysts.

Facile One‐Pot Hydrothermal Synthesis of Copper Nanowires and Their Impact on the EMI Shielding Capability of Epoxy Composites

AbstractIn this work epoxy nanocomposites containing varying content of copper nanowires (CuNW) were produced. The CuNW were synthesized using a facile one‐pot hydrothermal synthesis method. The composites were characterized for their electrical conductivity and electromagnetic interference (EMI) shielding effectiveness in the X‐band. The electrical conductivity of the epoxy composites was measured, and the composites containing 12 wt % CuNW demonstrated percolated behavior and exhibited a frequency‐independent conductivity value of 1.76 × 10−6 S m−1 in the range of 25–200 Hz. The 12 wt % CuNW sample demonstrated an EMI shielding effectiveness value of 6.5 dB, which corresponds to 77.1 % attenuation of the incident electromagnetic wave. Furthermore, an absorption‐dominated shielding mechanism was observed in these composites.

A new route for fast synthesis of copper nanowires and application on flexible transparent conductive films

Copper nanowires (CuNWs) have been attracting a lot of attention as an alternative to silver nanowires for next generation transparent conductors because of their favorable electric conductivity, mechanical properties, abundance, and low cost. Here, we report a new route using copper hydroxide as precursor, diethylenetriamine as complexing agent, and glucose as reducing agent, by which CuNWs can be acquired within a short reaction time of 10 min and a mild temperature of around 80℃. The effect of reaction temperature, copper precursor concentration, and glucose concentration on the morphology and dimensions of the synthesized CuNWs were investigated. CuNWs of 37 nm in diameter and 17 µm in length were incorporated in an ethylene vinyl acetate (EVA)-coated transparent conductive film, which offered a relative visible light transmission of 91% and a sheet resistance of 48 Ω/sq.

Copper(I)-alkylamine mediated synthesis of copper nanowires.

Formation of a Cu(i)-alkylamine complex is found to be the key step for Cu(ii) ions to reduce to Cu(0) in the presence of glucose. Also, alkylamines in Cu nanowire synthesis serve triple roles as a reducing, complexation and capping agent. Alkylamines reduce Cu(ii) to Cu(i) at above 100 °C and protect the Cu(i) by forming a Cu ion-alkylamine coordination complex with a 1 : 2 ratio in an aqueous solution. With respect to the 1 : 2 complex ratio, the additional free alkylamines ensure a stable Cu(i)-alkylamine complex. After completion of Cu(i)-Cu(0) reduction by glucose, alkylamines remain on Cu(0) seeds to regulate the anisotropic growth of Cu nanocrystals. Long-chain (≥C16) alkylamines are found to help produce high-quality Cu nanowires, while short-chain (≤C12) alkylamines only produce CuO products. Furthermore, Cu nanowire synthesis is found to be sensitive to additional chemicals as they may destabilize Cu ion-alkylamine complexes. By comparing the Cu(i)-alkylamine and Maillard reaction mediated mechanism, the complete Cu nanowire synthesis process using glucose is revealed.

Fast microwave-assisted synthesis of copper nanowires as reusable high-performance transparent conductive electrode

We report the microwave synthesis of copper nanowires (CuNWs) by using alkylamine-mediated approach. The aspect ratio of CuNWs of this study was two–fold compared to the previous microwave-assisted synthesis study. In addition, we showed that microwave synthesis could produce high aspect ratio CuNWs in a much shorter time compared to conventional method. Purification process of CuNWs was done via a simple and fast centrifugation method using water-hydrophobic organic solvent system. We also show the importance of purification process on the performance of the fabricated transparent conductive electrode (TCE) films. Purified CuNWs TCE showed a low sheet resistance of 35 Ω/sq with high transparency of 81% (at λ550 nm). Furthermore, we demonstrated how the retreatment of acetic acid was able to assist CuNWs to regain its high conductivity even after five cycles of repetitive continuous oxidation process.

Enhancement of Thermal Conductivity of Poly(methylmethacrylate) Composites at Low Loading of Copper Nanowires

We report the synthesis of copper nanowires (CuNWs) and the enhanced thermal conductivity of poly(methylmethacrylate) (PMMA) composites at low-loading fractions of CuNW. The scanning electron microscope, X-ray diffractometer, thermal diffusivity meter, high-resistance meter, universal testing machine, and thermogravimetric analyzer were used to investigate the properties of CuNW/PMMA composites. The elongation strain to failure, toughness, and thermal stability of the PMMA composites significantly increased with increasing contents of CuNW. The CuNW/PMMA composites showed the thermal conductivity and volume resistivity of 0.85 W/mK and 7×1010Ω·m, respectively, at 2.0 wt% of CuNW. The significant improvement of thermal conductivity is attributed to the well-dispersed CuNWs in the PMMA matrix and the high aspect ratio of CuNWs. The experimental results of thermal conductivity fitted well with the Agari model.

In Situ Seed-Mediated High-Yield Synthesis of Copper Nanowires on Large Scale.

Copper nanowires (Cu NWs) are among ideal candidates for fabricating various advanced nanodevices, especially flexible electronics and transparent conductive electrodes. However, although many efforts have been made, the commercialization of Cu NWs is still difficult. Herein, we report an in situ seed-mediated two-step strategy to synthesize well-defined Cu NWs in high yield. In the first step, that is, seed formation process, most Cu ions (85%) in situ transform to nondecahedral Cu nanodots (NDs). These Cu NDs can promote the formation of decahedral multiply twinned particles (DMTPs) and the subsequent growth of Cu NWs by selectively inhibiting the spontaneous ripening of nanoparticle (NP) byproducts in the second step. The amount and quality of Cu NDs play an important role in high-yield production of Cu NWs, and the yield was successfully increased to 2.4 times higher than that of the conventional methods. Furthermore, an effective shaking-rotating purification technique was developed to fully separate Cu NWs from the final product solution. After scaling up the reaction, 50 g of high-quality Cu NWs can be produced with a uniform size and high aspect ratio at a very low material cost of $ 0.99/g. These promising results not only provide a high-yield and low-cost synthetic route but also can promote the widespread commercialization of Cu NWs in advanced nanodevices.

Bio-based synthesis of oxidation resistant copper nanowires using an aqueous plant extract

Copper nanowires have recently emerged as promising nanomaterials for transparent conducting electrodes applications, however, their production commonly involves the use of harmful reagents. In this study, we describe for the first time a simple and cost-effective bio-based synthesis of copper nanowires using an aqueous plant extract (Eucalyptus globulus) as the reducing/stabilizing agent and oleic acid and oleylamine as surfactants. Well-dispersed crystalline copper nanowires (λmáx = 584–613 nm) were obtained with average diameters in the nanometric range (44 and 145 nm) and lengths in the micrometric range (from 5 to dozens of micrometres) using extract concentrations between 10 and 50 mg mL−1. Moreover, the aspect ratio of these nanowires can be adjusted (from around 14–20 to 160–400) by changing the experimental conditions, namely the use of oleic acid. Phenolic compounds were found to have a key role in this bioreduction process allowing to obtain practically only nanowires (without other morphologies). Nevertheless, the use of oleic acid/oleylamine is essential to manipulate their size and aspect ratio. Most importantly, these bio-based copper nanowires were found to be resistant under storage in ethanol and when submitted to air exposure, both for 2 weeks, certainly due to the adsorption of antioxidant biomolecules (phenolic) at their surface, thus avoiding the use of other polymeric protective layers. The conductivity of the CuNWs was found to be 0.009 S cm−1. As a result, this study opens a new standpoint in this field, “closing the door” to the use of hazardous reagents and synthetic polymeric protective layers, on the production of stable copper nanowires with potential application as conductive materials.

Synthesis of Copper Nanowires and Their Antimicrobial Activity on Strains Isolated Persistent Endodontic Infections.

Copper nanowires, Cu-NWs may have a good antimicrobial effect in endodontic treatment. The objective of this work was to synthesize, characterize and evaluate the antibacterial activity of Cu-NWs on strains obtained from human root canal. A wide distribution of Cu-NWs diameters from 30 to 90 nm was obtained with lengths ranging from 5 to 40 μm. Structural analysis of Cu-NWs showed crystalline planes, which corresponded to Cu, with preferential growth in the direction [110]. The geometric mean MICs was of 289.30 μg/mL, with a MIC50 of 256 μg/mL and a MIC90 of 512 μg/mL for Cu-NWs. Cellular viability of 28 a biofilm tends to decrease the longer it is exposed to Cu-NWs. Synthesized and characterized Cu-NWs have a good antimicrobial effect against clinical strains used in the present study and has a potential to be used for disinfection of the root canal system.

Synthesis of copper nanowires via a liquid phase reduction process

ABSTRACTCopper nanowires (Cu NWs) were successfully synthesized via a method of liquid phase reduction by using hydrazine hydrate as reducing agent, ethylenediamine (EDA) as structure-directing agent. The impact of various factors on Cu NWs was analyzed by orthogonal experiment. Cu NWs were characterized by SEM, XRD, and TEM techniques. The results show that: the Cu NWs were free of oxidation, and were highly oriented along the (111) direction. The sequence of factors which impact the length and diameter of Cu NWs is: hydrazine hydrate - NaOH - EDA - reaction temperature. Considering all the factors, to synthesize Cu NWs, the optimal conditions are as follows: 4mL EDA, 50mL NaOH, 10 mL1% hydrazine hydrate, 10 mL 10% hydrazine hydrate, 80°C.

Synthesis of copper nanowires and its application to flexible transparent electrode

The well-dispersed copper nanowires (Cu NWs) with diameter of about 65 nm and length of 70 μm were successfully synthesized by a rapid and facile hydrothermal method. Then the nano-network electrode based on Cu NWs was achieved by filtration and a wet treatment process. The initial Cu NWs films were almost not conductive. Post-treatment with acetic acid for 30 s at room temperature leads to Cu NWs films with excellent conductivity-transmittance performances (e.g., 60 Ω/sq. at 90% transparence), which is better than the commercial ITO/PET flexible electrodes. Additionally, Cu NWs films also possess good flexibility, no evident degradation of conductivity for the films was observed during 1000 cycles of bending test.

Hydrothermal Synthesis of Copper Nanowires as Advanced Conductive Agents for Lithium Ion Batteries.

Copper nanowires (CuNW) are synthesized via one-pot hydrothermal method and test as advanced conductive agents for lithium ion batteries. Anode prepared with CuNW and graphite show improved rate ability and excellent cycling stability even at high rate. AC-impedance of CuNW added electrode is much lower than that of electrodes containing carbon black only. This implies the CuNW could lower the electronical resistance.

The Role of Cuprous Oxide Seeds in the One‐Pot and Seeded Syntheses of Copper Nanowires

This paper demonstrates that Cu2O nanoparticles form in the early stages of a solution-phase synthesis of copper nanowires, and aggregate to form the seeds from which copper nanowires grow. Removal of ethylenediamine from the synthesis leads to the rapid formation of Cu2O octahedra. These octahedra are introduced as seeds in the same copper nanowire synthesis to improve the yield of copper nanowires from 12% to >55%, and to enable independent control over the length of the nanowires. Transparent conducting films are made from nanowires with different lengths to examine the effect of nanowire aspect ratio on the film performance.

Synthesis of Copper Nanowires in Highly Ordered Nanoporous Anodic Alumina Template

In this paper, the fabrication of nanoporous anodic alumina template from aluminum foil has been demonstrated using hard anodization process. Copper nanowires arrays were fabricated using continuous and pulse electrodeposition technique into the porous alumina template. Copper nanowires are grown su ccessfully in anodic alumina nano template. The pulse deposition technique using 50 ms off -time showed better quality samples than those madewith continuous deposition technique due to cooling of barrier layer during the off -time.

A simple route for the synthesis of copper nanowires

We have synthesized Cu nanowires via a simple process using both thermal evaporation and CuCl powders. In this method, complicated processes and special instruments are not required to synthesize Cu nanostructures. In addition, we have used commercial CuCl powders as a precursor. There have been no reports on the preparation of Cu nanostructures using simple instruments together with a commercial source material as in this study. Cu nanostructures of various morphologies were formed at relatively low temperature. The microstructure of the Cu nanostructures was investigated using HRTEM images and SAD pattern analysis.

Electrochemical synthesis of copper nanowires in anodic alumina membrane and their impedance analysis

Copper (Cu) nanowires having 20 nm diameter were fabricated by electrodeposition within the pores of anodic alumina membrane (AAM) by using template synthesis method. The morphology and composition of nanowires was characterized by scanning electron microscope (SEM) and energy dispersive X-ray fluorescence (EDXRF). X-ray diffraction (XRD) was utilized for structural characterization. Impedance of nanowires was measured at room temperature by leaving the nanowires embedded in the insulating template membrane and small decrease in impedance was found at higher frequency above 10 kHz.

Ordered arrays of copper nanowires enveloped in polyaniline nanotubes

Copper nanowires enveloped in polyaniline (PANI) nanotubes were obtained by ‘second order’ electrodeposition into the pores of anodic porous alumina. The templated synthesis of copper nanowires was performed by both potentiostatic and galvanostatic methods. The morphology of the polyaniline nanotubes, copper nanowires as well as the copper-filled polyaniline nanotubes was investigated by means of scanning electron microscopy. The copper nanowires were protected from corrosion and oxidation by the PANI nanotubes. Energy-dispersive X-ray spectroscopy was performed for the microanalysis of the copper deposition into the polyaniline nanotubes. Cyclic voltammetry was employed to assess the electrochemical properties of the obtained nanostructures as well as the influence of the copper nanowires synthesis method on the properties of filled polyaniline nanotubes.

WITHDRAWN: Synthesis of copper nanowires using relativistic Si +6 irradiation followed by chemical etching and characterization

WITHDRAWN: Synthesis of copper nanowires using relativistic Si +6 irradiation followed by chemical etching and characterization

EFFECT OF MICROWAVE IRRADIATION ON COPPER NANOWIRES SYNTHESIZED BY ELECTROCHEMICAL DEPOSITION THROUGH ION TRACK MEMBRANES AS TEMPLATES

15 μm thick polycarbonate films were irradiated with Ni ions (11.64 MeV/n) having fluence of the order of 106 ions/cm2. Irradiated foils were etched chemically in 6N NaOH solution at 50°C for 12 minutes to obtain the cylindrical pores having average diameter of 100 nm. Cylindrical pores in these membranes have been used as templates for the synthesis of copper nanowires. A two-electrode electrochemical cell was used for copper electrodeposition in porous polycarbonate templates from acidic copper sulphate solution at 29 ± 1° C . The morphology of copper nanowires were studied by means of scanning electron microscopy (SEM). Effects of microwave treatment on these nanowires were also studied.

Electrostatically Dissipative Polystyrene Nanocomposites containing Copper Nanowires

AbstractSummary: A scalable synthesis of copper nanowires by alternating current electrodeposition into porous aluminium oxide was used to produce multigram quantities of 16 nm diameter by >2 µm long nanowires. Polystyrene nanocomposites were prepared by solution processing. The composites containing unpassivated nanowires were non‐uniformly dispersed and showed electrical percolation at ≈2 vol.‐% Cu loading, while the composites containing HSC18H37‐passivated nanowires were uniformly dispersed, but remained resistive up to at least 10 vol.‐% Cu loading.Copper nanowires prepared by alternating current electrodeposition into porous aluminium oxide templates.magnified imageCopper nanowires prepared by alternating current electrodeposition into porous aluminium oxide templates.