Effect of temperature on the wettability of CuO nanowires (original) (raw)
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.
Chemical bath deposition of thin films of CuO nanorods and their characterisation
International Journal of Nanomanufacturing, 2010
CuO is a p-type semiconducting material with room temperature band gap energy nearly at 1.4 eV for the bulk systems. Here, we present a simple one-pot chemical bath deposition of CuO thin films with nanorod-like crystallites and excellent uniformity of the surface, from an alkaline solution of Cu 2+ ions. Structural characterisations of the films were carried out by studying XRD patterns and FESEM, EDX and AFM analyses. Broad FWHM of the XRD peaks indicates the formation of nanocrystals. Nanorod-like grain growth along c-axis is evident from the FESEM image. Average diameter of the nanorods was found to be ~40 nm. Optical absorption spectrum (UV-VIS) of the films showed a blue shift in the band gap energy to ~2.0 eV, due to quantum confinement effect showed by the nanocrystals. Various electrical measurements were also carried out.
Copper-oxide Nanowires based Humidity Sensor
arXiv: Applied Physics, 2017
This paper presents investigated results of copper-oxide nanowires used as a humidity sensor. Copper-oxide nanowires films were grown over cross-comb type gold electrodes on a SiO2 substrate using thermal annealing technique, and its humidity sensitive characteristics were investigated through resistance across the gold electrodes. These copper-oxide nanowires films revealed high sensitivity and long-term stability with fast response time. It was found that resistance across gold electrodes of the fabricated sensor decreases with increase in humidity almost linearly on a logarithmic scale. It appears that copper-oxide nanowires can be used as low-cost humidity sensor with high output reliability and reproduction rate. The observations were carried out at room temperature (RT) and relative humidity (RH) in the range of 6% to 97%.
The Roles of Hydrazine and Ethylene Diamine in Wet Synthesis of Cu Nano Wire
Indonesian Journal of Chemistry, 2017
It has been done wet synthesis Cu nano wire using CuNO3 as precursor and hydrazine as a reductor agent and ethylene diamine as polymer capping agent. The synthesis was done in excessive sodium hydroxide using different volume of hydrazine and ethylenediamnie (EDA) to seek the optimum condition of the targeted nano wire. The study revealed that the condition in obtaining various nano wire sizes, in terms of length and diameter, to be possibly controlled by varying the volume of hydrazine and ethylenediamnie.
Hydrophobicity and tribology of large-area textured copper with nanogrown copper oxide
Surface Innovations, 2016
Copper (Cu) is widely used as an engineering material for automotive industries. Herein, a two-step surface innovation process was evolved to enhance the hydrophobicity and wear resistance of the copper surface. Rapid fabrication of large-area texturing was performed by the abrasive water jet technique followed by nanogrowth of copper oxide (CuO) film on the copper substrate. Increased hydrophobicity is observed for textured copper (120°) and copper with nanogrown CuO (133°) compared to that of copper without these features (63°). It may be noted that synergistic texturing and nanogrowth of CuO has resulted in the highest contact angle (155°). X-ray photoelectron spectroscopy revealed the least percentage contribution of Cu–OH group to synergetic texture and nanogrowth (1·25 %). Further, the fretting wear test divulged the high wear resistance of synergistically textured copper with nanogrown CuO, as its coefficient of friction was lowest (0·46) when compared with that of copper (0·...
Journal of Physical Chemistry C, 2009
We report the synthesis of different Cu(OH) 2 and CuO nanostructures (nanowires, rectangles, seedlike, beltlike, and sheetlike) in a solution phase with high yield at low cost by simple reduction of aqueous solution of copper nitrate (Cu(NO 3 ) 2 ) 0.2 M) with different alkaline solutions of sodium hydroxide (NaOH ) 0.1, 0.25, 0.50, 0.75, and 1.0 M). The morphology of the synthesized nanostructures is significantly influenced by the feeding concentration of alkaline NaOH solution. Cu(OH) 2 rectangles and nanowires can be readily obtained by the reduction of Cu(NO 3 ) 2 solution with different molar concentrations of NaOH solution and the synthesized nanomaterials get transformed into different nanostructures of CuO by subsequent heat treatment at 80°C for half an hour. Well-defined rectangle-like structures of hydrated copper hydroxide Cu(OH) 2 · H 2 O and different CuO nanostructures, such as seedlike, beltlike, and sheetlike, were synthesized by thermal dehydration of corresponding different shaped and sized Cu(OH) 2 nanomaterials. The Raman spectra of different CuO nanomaterials obtained at different molar concentrations of NaOH (0.25, 0.50, 0.75, and 1 M) were recorded in the region 1050-1300 cm -1 . A tentative mechanism has been given for the formation and transformation of different nanostructures.