Effect of temperature on the wettability of CuO nanowires (original) (raw)
Related papers
Journal of the Chilean Chemical Society, 2010
CuO nanowires were successfully made through a simple wet chemical method at room temperature by immersing on copper sheets in a 4 M ammonia solution for 4 days and then subjecting it to heat treatment. Immersion time and heat treatment have an important effect on the length, diameter, and density of the CuO nanostructures. X-ray powder diffraction (XRD) patterns indicated that the samples are composed of a single phase, CuO. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy studies showed that the wet-treated samples consisted of nanofiber-like structures of monoclinic CuO, while the heat-treated samples consisted of well-defined nanowires which also exhibited the monoclinic phase.
Synthesis and characterization of CuO nanowires by a simple wet chemical method
Nanoscale Research Letters, 2012
We report a successful synthesis of copper oxide nanowires with an average diameter of 90 nm and lengths of several micrometers by using a simple and inexpensive wet chemical method. The CuO nanowires prepared via this method are advantageous for industrial applications which require mass production and low thermal budget technique. It is found that the concentration and the quantity of precursors are the critical factors for obtaining the desired one-dimensional morphology. Field emission scanning electron microscopy images indicate the influence of thioglycerol on the dispersity of the prepared CuO nanowires possibly due to the stabilization effect of the surface caused by the organic molecule thioglycerol. The Fourier transform infrared spectrum analysis, energy dispersive X-ray analysis, X-ray diffraction analysis, and X-ray photoemission spectrum analysis confirm clearly the formation of a pure phase high-quality CuO with monoclinic crystal structure.
Beilstein Journal of Nanotechnology
Electrochemical impedance spectroscopy was applied for studying copper oxide (CuO) nanowire networks assembled between metallic microelectrodes by dielectrophoresis. The influence of relative humidity (RH) on electrical characteristics of the CuO nanowire-based system was assessed by measurements of the impedance Z. A slight increase of Z with increasing RH at low humidity was followed by a three orders of magnitude decrease of Z at RH above 50–60%. The two opposite trends observed across the range of the examined RH of 5–97% can be caused by water chemisorption and physisorption at the nanowire interface, which suppress electronic transport inside the p-type semiconductor nanowire but enhance ionic transport in the water layers adsorbed on the nanowire surface. Possible physicochemical processes at the nanowire surface are discussed in line with equivalent circuit parameters obtained by fitting impedance spectra. The new investigation data can be useful to predict the behavior of n...
Copper nanowire arrays surface wettability control using atomic layer deposition of TiO2
Russian Journal of Applied Chemistry, 2016
Template two step electrodeposition method and atomic layer deposition were used to synthesize copper nanowires of varied length (1.2 to 26.2 μm) and copper nanowires coated with titanium dioxide. As a result of the atomic layer deposition of TiO 2 , coated nanowires demonstrated an up to 10-fold decrease in the wetting angle, compared with uncoated nanowires. It was found the dissipation rate is substantially higher for nanowires coated by the atomic layer deposition method (100 s) as compared with the uncoated copper nanowires (400 s), which assumes the positive properties of water propagation along the surface, necessary for improving the heat transfer. It was also found that the water contact angle for uncoated nanowires and those coated with TiO 2 by the atomic layer deposition (ALD) gradually increases as the samples are kept in air. A gradual increase in wettability was also observed for smooth silicon wafers coated by ALD of TiO 2 , which were exposed to air. On the coated silicon substrates, the wetting angle gradually increased from 10° to approximately 56° in the course of four days. In addition, it was shown that copper nanowires coated with TiO 2 by the atomic layer deposition method have an excellent corrosion resistance, compared with uncoated nanowires, when brought in contact with air and water.
Synthesis and Characterization of CuO Nanowires
2006
Synthesis of copper oxide nanowires was done heating up copper wires in wet ambient air at 400 and 500degC. The existence of nanowires was confirmed by SEM images and EDX spectroscopy. Nanowires were not formed in nitrogen ambient. The diameters of synthesized nanowires are between 30 to 160 nm and lengths up to 39 mum. SEM image shows that CuO nanowires were formed on top of the oxide grains. Vapor-solid growth mechanism is also suggested for the growth of this nanowire.
Synthesis of CuO Nanowires on Waste Copper Wires
2006
∗ Corresponding author: Tel.: +603-8921-6928; Fax: +603-8925-9080. Email: cfdee@vlsi.eng.ukm.my (Dee Chang Fu) ... Synthesis of CuO Nanowires on Waste Copper Wires ... CF Dee*, Muhammad Yahaya, Muhamad Mat Salleh and Burhanuddin Yeop Majlis
CuO Nanowire-Based Humidity Sensor
IEEE Sensors Journal, 2000
The authors report the growth of CuO nanowires on an oxidized Cu wire and the fabrication of a CuO nanowire humidity sensor. It was found that we could transform a Cu wire into CuO/Cu 2 O/Cu core-shell tri-layers covered with high density CuO nanowires by thermal annealing. It was also found that steady state currents of the sensor were about 2.44, 2.32, 2.23, and 2.15 µA, respectively, when measured with 20, 40, 60, and 80% relative humidity. Furthermore, it was found that sensing property of the fabricated device was stable and reproducible.
CuO nanostructures on copper foil by a simple wet chemical route at room temperature
Uniform CuO nanostructures have been synthesized on copper foil substrates by oxidation of Cu in alkaline condition by a simple wet chemical route at room temperature. By controlling the alkaline condition (pH value) different CuO nanostructures like nanoneedles, self-assembled nanoflowers and staking of flake-like structures were achieved. The phase formation and the composition of the films were characterized by X-ray diffraction and energy dispersive analysis of X-ray studies. X-ray photoelectron spectroscopic studies indicated that the samples were composed of CuO. The morphologies of the films were investigated by scanning electron microscopy. A possible growth mechanism is also proposed here. Band gap energies of the nanostructures were determined from the optical reflectance spectra. The different CuO nanostructures showed good electron field emission properties with turn-on fields in the range 6–11.3 Vmm1 . The field emission current was significantly affected by the morphologies of the CuO films
Formation of CuO nanowires on Cu foil
Chemical physics letters, 2004
Cupric oxide, CuO, has many interesting properties. It has a monoclinic crystal structure, and is a p-type semiconductor with a narrow band gap (1.2 eV) [1]. It is also a Mott insulator (3d transition metal monoxide), the electronic structures of which cannot be simply described within the ...
Nanomaterials, 2020
Size distribution, Young’s moduli and electrical resistivity are investigated for CuO nanowires synthesized by different thermal oxidation methods. Oxidation in dry and wet air were applied for synthesis both with and without an external electrical field. An increased yield of high aspect ratio nanowires with diameters below 100 nm is achieved by combining applied electric field and growth conditions with additional water vapour at the first stage of synthesis. Young’s moduli determined from resonance and bending experiments show similar diameter dependencies and increase above 200 GPa for nanowires with diameters narrower than 50 nm. The nanowires synthesized by simple thermal oxidation possess electrical resistivities about one order of magnitude lower than the nanowires synthesized by electric field assisted approach in wet air. The high aspect ratio, mechanical strength and robust electrical properties suggest CuO nanowires as promising candidates for NEMS actuators.