Perspectives of nanoscience and nanotechnology

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Authors: Lucky Mashudu Sikhwivhilu, Suprakas Sinha Ray, Neil John Coville
Abstract: Nanomaterials are of great importance for their versatile applications in gas sensors, solar cells and photocatalysis due to their unique optical, electrical and catalytic properties. Titania derived nanotubular and nanospherical particles with a titanate structure were synthesized using a hydrothermal procedure in the presence of very concentrated solutions of KOH and NaOH respectively. Both nanostructures were found to exhibit relatively large specific surface areas, i.e. 280 and 303 m2/g for materials treated in NaOH and KOH respectively. The morphological and structural properties were characterised by TEM, SEM, Raman spectroscopy and XRD.
Authors: J. Kisielewski, Kamil Postava, I. Sveklo, A. Nedzved, P. Trzciński, Andrzej Maziewski, B. Szymański, M. Urbaniak, Feliks Stobiecki
Abstract: The magnetic properties of an ultrathin cobalt film were modified by a focused femtosecond pulsed laser beam. The Co wedge, with a thickness ranging from 0 to 2 nm, sandwiched by Au films was prepared using ultra-high vacuum magnetron sputtering on a mica substrate. The modifications of the laser induced magnetic anisotropy were investigated using magneto-optic Kerr microscopy and MFM/AFM techniques. The laser induces: (i) local reorientation of magnetization from an in-plane to a perpendicular state and (ii) an increase of the coercivity field. A corresponding increase of the perpendicular magnetic anisotropy is discussed considering an improvement of the Co/Au interfaces.
Authors: M. Sokół, Z. Gburski
Abstract: First principle simulations for the nanosystems Kn(C60)2, (n = 1, 2) composed of two fullerene (C60) molecules and one or two potassium (K) atoms have been undertaken. A very effective delocalization of the 4s1 valence electron of potassium was observed, the potassium atom in practice becomes an ion. The adsorption binding energy of potassium atom(s) is Ea = - 1.923 ± 0.04 eV, - 3.819 ± 0.04 eV for K(C60)2 and K2(C60)2, respectively. The reported large values of adsorption energy should cause a significant change in electronic properties of alkali doped fullerene clusters.
Authors: A. Piątek, A. Dawid, K. Górny, Roman Nowak, Z. Gburski
Abstract: The nanosystem composed of only as few as seven endohedral fullerene K+@C60 molecules was simulated using the MD method. The interaction was taken to be the full site-site pairwise additive Lennard-Jones (LJ) potential, which generates both translational and anisotropic rotational motions of each endohedral fullerene. The atomically detailed MD simulations allow the dynamics of the motion of K+@C60 molecule inside the cluster to be analysed. The radial distribution function, the mean square displacement, the translational velocity correlation functions and the Lindemann index of endohedral fullerene have been calculated for several energies of the nanosystem. The solid/liquid phase transition and the existence of the liquid phase in the endohedral potassium ion fullerene cluster was found.
Authors: W. Gwizdała, A. Dawid, Z. Gburski
Abstract: The molecular dynamics (MD) technique was used to investigate the nano droplet composed of twenty mesogene molecules 4-cyano-4-n-pentylbiphenyl (5CB). The 5CB molecules were treated as rigid bodies, the intermolecular interaction was taken to be the full site-site pairwise additive Lennard-Jones (LJ) potential plus a Coulomb interaction. The radial distribution functions in the temperature range from 150 to 400 K, were calculated as well as the linear and angular velocity autocorrelation functions. In addition the total dipole moment autocorrelation function and dielectric loss of (5CB)22 mesogene cluster were calculated and the liquid crystal ordering in the nanoscale system was studied up to its vaporization temperature.
Authors: M. Sarah Mohlala, Suprakas Sinha Ray
Abstract: This paper describes the preparation, characterization and properties of nanostructured composite materials based on poly(butylene adipate-co-polycaprolactam) (PBA-co-PCL)/multiwalled carbon nanotubes (MWCNTs) and polycaprolactone (PCL)/MWCNTs. The polymer/MWCNTs nanocomposites were prepared by mixing the polymers with various amounts of MWCNTs using both solution and melt blending processes. The dispersion of MWCNTs into the polymer matrix was analyzed by transmission electron microscopy (TEM) and the thermal stability of the nanocomposites was studied by thermal gravimetric analysis (TGA). Differential scanning calorimetry (DSC) was used to study the crystallization and melting behaviour of the polymer matrices containing the MWCNTs.
Authors: A.T. Sobczyk, A. Jaworek, Eryk Rajch, Maria Sozańska
Abstract: A novel method to synthesize carbon fibres using low-current electrical-discharge plasma in hydrocarbon vapours is presented in the paper. The low-current arc discharge of positive polarity was generated between a stainless steel needle, and a nickel alloy plate, over a voltage range from 2 kV to 30 kV. The discharge was stabilised by a high series resistance (1 – 12.5 M'). The experiments were carried out in an argon atmosphere at normal temperature and atmospheric pressure. The arc discharge of current in the range of 1 to 4 milliamps was found to be a potentially effective method for the production of carbon fibres. The diameter of the fibres varied from about 20 to 120 μm with a growth rate of about 0.5 mm/s.
Authors: A. Piątek, Roman Nowak, Z. Gburski
Abstract: A small titanium-decorated fullerene cluster (C60[TiH2]6)7 was studied by MD simulation over a wide range of energy, from the solid state to the vaporization of the nanosystem. The low energy, solid state structure of the cluster was obtained as a deformed pentagonal bipyramid. Several physical characteristics: the radial distribution function, the mean square displacement, the translational velocity autocorrelation function, translational diffusion coefficient, Lindemann index, etc., were calculated for a wide range of energy in the system.
Authors: Jing Lu, Thomas J. Webster
Abstract: Atherosclerosis, which is caused by endothelial dysfunction, vascular inflammation, and the build-up of lipids, cholesterol, calcium, and cellular debris within the intima of the vessel wall, is one of the most important complications of health. Vascular stenting is the procedure of implanting a thin tube into the site of a narrow or blocked artery due to atherosclerosis. However, the application of vascular stents using conventional metals is limited because the implantation process will cause significant injury to the vascular wall and endothelium, which functions as a protective biocompatible barrier between the tissue and the circulating blood, resulting in neointima hyperplasia followed by the development of long-term restenosis. The objective of this in vitro study was to investigate the endothelial cell function, especially their adhesion behaviour, on highly controllable features on nanostructured surface. Considering the importance of the endothelium and its properties, highly controllable nanostructured surface features of titanium, a popular vascular stent metal, were created using E-beam evaporation to promote endothelialization and to control the direction of endothelial cells on vascular stents. Endothelial cells are naturally aligned with the blood flow in the body. In this manner, the present in vitro study provides much promise for the use of nanotechnology for improving metallic materials for vascular stent applications.
Authors: A. Jaworek, A. Krupa, A.T. Sobczyk, M. Lackowski, T. Czech, Seeram Ramakrishna, S. Sundarrajan, Damian Pliszka
Abstract: The paper presents experimental results of electrospray deposition of nanopowder onto microfibers. The process is designed to form fibrous filters with an enhanced collection efficiency in the submicron range by covering the fabric with a catalytic material. Polyamide fibres were coated with Al2O3, ZnO, MgO, or TiO2 nanoparticles. The structures obtained were porous at the nanometer scale which increased the total surface area of the catalyst.

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