Journal of Nano Research Vol. 60

Abstract: This research investigates the effect of surface roughness, water temperature, and pH value on the wettability behaviour of copper surfaces. An electron beam physical vapour deposition technique was used to fabricate 25, 50, and 75 nm thin films of copper on the surface of copper substrates. Surface topographical analysis, of the uncoated and coated samples, was performed using an atomic force microscopy device to observe the changes in surface microstructure. A goniometer device was then employed to examine the surface wettability of the samples by obtaining the static contact angle between the liquid and the attached surface using the sessile drops technique. Waters of pH 4, 7, and 9 were employed as the contact angle testing fluids at a set of fixed temperatures that ranged from 20°C to 60°C. It was found that increasing the deposited film thickness reduces the surface roughness of the as-prepared copper surfaces and thus causing the surface wettability to diverge from its initial hydrophobic nature towards the hydrophilic behaviour region. A similar divergence behaviour was seen with the rise in temperature of water of pH 4, and 9. In contrast, the water of pH 7, when tested on the uncoated surface, ceased to reach a contact angle below 90^o. It is believed that the observed changes in surface wettability behaviour is directly linked to the liquid temperature, pH value, surface roughness, along with the Hofmeister effect between the water and the surface in contact.

Abstract: Pb doped ZnS nanotubes films have been deposited on glass and Si (100) substrates by a thermal evaporation technique. Energy dispersive spectroscopy (EDX) analysis has been used to identify the element’s compositions. Pb concentration in the prepared films was increased from 0 to about ~6 wt. %. The X- Ray Diffraction (XRD) pattern exhibited the wurtzite structure of ZnS with (002) preferred orientation. It shows that the calculated grain size increased with increase in Pb concentration. XRD analysis was also used to determine the strain in the films. Morphology and thickness of the films were obtained from surface and cross section of the films, using scanning electron microscopy (SEM) images. SEM images have confirmed the ZnS nanotubes and modifications of the morphology when adding Pb. Atomic force microscope (AFM) and SEM characterization have been shown dense structure and demonstrated the growth of spherical forms with nanostructure (nanotubes not created) for a film deposited without doping (0 wt. %). The transparency of the films has been deduced from UV-Vis spectra, where the band gap increased with increase in Pb concentration

Abstract: In this work we study the influence of the laser pulses silver nanoparticles productivity during laser ablation of silver immersed in liquid. Ag nanoparticles were synthesized by pulsed laser ablation of Ag targets in ethanol using the (1064 nm, Q-switched, Nd:YAG) laser with energy of 140 mJ per pulse. UV-Visible absorption spectra were used for the characterization and comparison of products. The non-linear refractive index and absorption coefficient of silver nanoparticles were investigated using a single beam z-scan technique; the excitation source was a continuous wave (CW) of 650 nm diode laser with a beam power of 50 mW. All investigated samples showed negative-induced non-linear refractive indices.

Abstract: For a number of years, nanomaterials have been considered as a perfect solution to maintain the stability of different cultural heritage materials. In the present trial, hydroxyapatite nanoparticles (HAp-NPs) have been synthesized via the wet chemical reaction of calcium nitrate and ammonium hydroxide. Then, the possible efficiency of HAp-nanoparticles was evaluated to improve restoration formulas for some archaeological lime-based plasters. A broad series of analytical methods, namely OM, FE-SEM, TEM, AFM, XRD and BET surface area-pore size analysis, was selected for characterizing the archaeological samples and to rate the experimental tests. Further, the physical-mechanical behavior of samples was measured. The emulated modifications induced by the HAp-NPs treatment have been evaluated and discussed.

Abstract: Many mural paintings stored in museums suffer from the heavy loaded added gypsum layers to the background. Currently anew way will be used for support the back ground of mural painting using the nanocalcium hydroxide which added to the background of it. This nanomaterial is smoothly penetrate inside the mural painting structure then it combines with CO₂ producing CaCO₃ the original binder in all mural paintings especially fresco paintings, The mechanical characteristics were tested to determine the change in properties of the interior structure of the treated Coptic fresco painting