Search results for "nanoparticle"
showing 10 items of 2198 documents
Morphology and Properties of Polyethylene/Clay Nanocomposite Drawn Fibers
2008
The influence of an elongational flow on the morphology of PE/clay nanocomposite drawn fibers was studied. An increase of the elastic modulus and the tensile strength as well as a decrease of the elongation at break are observed with increasing draw ratio. The applied elongational gradient orients the polymer chains and the clay particles along the spinning direction. When the applied flow results in the formation and the orientation of exfoliated nanoparticles, a pronounced increase of the mechanical properties is observed. The dispersed clay particles can be broken and oriented by the extensional flow, which might indicate a flow induced intercalated/exfoliated morphology transition.
Graphene oxide-silica nanohybrids as fillers for PA6 based nanocomposites
2014
Graphene oxide (GO) was prepared by oxidation of graphite flakes by a mixture of H2SO4/H3PO4 and KMnO4 based on Marcano's method. Two different masterbatches containing GO (33.3%) and polyamide-6 (PA6) (66.7%) were prepared both via solvent casting in formic acid and by melt mixing in a mini-extruder (Haake). The two masterbatches were then used to prepare PA6-based nanocomposites with a content of 2% in GO. For comparison, a nanocomposite by direct mixing of PA6 and GO (2%) and PA6/graphite nanocomposites were prepared, too. The oxidation of graphite into GO was assessed by X-ray diffraction (XRD), Micro-Raman spectroscopy, scanning electron microscopy (SEM), X-ray photoelectron spectrosco…
Novel Au NPs/Preyssler acid/TiO 2 nanocomposite for the photocatalytic removal of azo dye
2014
Abstract In this study, we introduced a novel nanocomposite consisting of Au nanoparticles decorated TiO 2 and Preyssler acid as a multifunctional photocatalyst linker molecule, in which gold ions reduced locally on the TiO 2 surface. The obtained nanocomposite has been characterized using Fourier Transform Infrared (FTIR), X-ray Diffraction (XRD), Electron Dispersive X-ray (EDX) Spectroscopy, Transmission Electron Microscopy (TEM) and Scanning Electron Microscope (SEM). Also, their photocatalytic activity has been studied for the degradation of model organic azo dye Malachite Green under UV light irradiation.
Au–NiOx nanocomposite for hot electron-assisted plasmonic photocatalysis
2020
Nanocomposites of metal–oxide semiconductors containing Au nanoparticles are emerging multifunctional materials for sunlight-driven highly efficient photocatalysis. Here we report a solution-processed nanocomposite synthesis of Au–NiOx nanocomposite films by slot-die coating and plotter printing in a straightforward in situ synthesis approach. Our study demonstrated a significantly enhanced photocatalytic decomposition reaction of MO upon exposure of Au–NiOx films to a sunlight simulator. The excellent photocatalytic activity is ascribed to the generation of hot carriers after LSPR excitation in Au NPs. Suitable band alignment between the valence band of NiOx and the Fermi level of Au NPs l…
Effect of Hydration Procedure of Fumed Silica Precursor on the Formation of Luminescent Carbon Centers in SiO 2 :C Nanocomposites
2019
The effect of hydration procedure of fumed silica precursor on photoluminescent properties of carbonized silica (SiO2:C) nanocomposite after chemo/thermal treatments is studied. Main structural effect is the formation of chemical bonding of phenyl groups to silica surface via multiple CSiO bonding bridges. Synthesized samples demonstrate very broad photoluminescence (PL) bands in near ultraviolet and visible ranges with maximum intensity dependent on temperature of thermal annealing. Two main trends in luminescence properties are: 1) hydration-induced blue shift of PL in comparison with PL of unhydrated series; 2) red shift of PL bands with increasing synthesis temperature regardless hydr…
NMR-investigation of the mechanism of silver mercaptide thermolysis in amorphous polystyrene
2007
Polymer-embedded silver clusters have been prepared by thermal decomposition of silver dodecylmercaptide previously dissolved in amorphous polystyrene. The morphology and structure of silver clusters have been determined by transmission electron microscopy (TEM) and large angle X-ray diffractometry (XRD), respectively. The mechanism involved in the thermolysis reaction was elucidated by different NMR techniques. The thermolysis produced thiol-derivatized silver clusters (i.e., silver clusters coated with a self-organized thiol monolayer, Agx(SC12H25)y) and had the effect of increasing the branching degree of polystyrene due to enhanced cross-linking.
Thermal stability of Au–TiO2 nanocomposite films prepared by direct liquid injection CVD
2015
Abstract Nanocomposite films composed of gold nanoparticles (AuNPs) embedded in a TiO 2 matrix have been prepared by direct liquid injection chemical vapor deposition process, using preformed nanoparticles and titanium isopropoxide as precursors. The spherical AuNPs about 4.1 nm in diameter were synthesized by using gold (III) chloride trihydrate and stabilized by thiol ligands. The depositions were carried out by performing at first oxide deposition, then gold nanoparticle one and capping with oxide. The morphology, structure; the chemical state and optical properties of nanocomposite films were characterized by scanning electron microscopy, Raman, X-ray photoelectron and UV–Vis absorption…
Imaging the Magnetic Reversal of Isolated and Organized Molecular-Based Nanoparticles using Magnetic Force Microscopy
2015
In the race towards miniaturization in nanoelectronics, magnetic nanoparticles (MNPs) have emerged as potential candidates for their integration in ultrahigh-density recording media. Molecular-based materials open the possibility to design new tailor-made MNPs with variable composition and sizes, which benefit from the intrinsic properties of these materials. Before their implementation in real devices is reached, a precise organization on surfaces and a reliable characterization and manipulation of their individual magnetic behavior are required. In this paper, it is demonstrated how molecular-based MNPs are accurately organized on surfaces and how the magnetic properties of the individual…
Cover Picture: Nanoscale Deposition of Single-Molecule Magnets onto SiO2 Patterns (Adv. Mater. 2/2007)
2007
The cover shows a schematic of scanning probe nanolithography based on the spatial confinement of an oxidation reaction within a water meniscus, and its application for fabricating ordered arrays of cationic Mn12 single-molecule magnets. Romero, Coronado, Garcia, and co-workers report on p. 291 that electrostatic interactions between the molecules and trapped charges within the nanodots drive the positioning of the molecules at the nanoscale.
Real-time manipulation of gold nanoparticles inside a scanning electron microscope
2011
Abstract The forces needed to overcome static friction and move 150 nm diameter Au nanoparticles on an oxidized Si substrate were measured in Normal and Shear oscillation modes inside a scanning electron microscope (SEM) in real time. The experimental setup consisted of a quartz tuning fork (QTF) mounted onto a high-precision 3D nanomanipulator used with a glued silicon or tungsten tip as a force sensor. Static friction was found to range from tens of nN to several hundred nN. Large variations in static friction values were related to differences in particle shape. Kinetic friction tended to be close to the detection limit and in most cases did not exceed several nN. The influence of therma…