Nanoparticles In Polymer Matrix Research Articles

Optical properties of metal–oxide nano-particles embedded in the polyimide layer for photovoltaic applications

Metal–insulator–semiconductor structures with metal–oxide nano-particles in polymeric matrix were fabricated for optoelectronic and photovoltaic applications. Then, the polymer layer has also possibility for an application to flexible devices. The optical absorbance spectra of Cu 2O, In 2O 3, and SnO 2 nano-particles with the diameter of 10–50 nm range embedded in the polyimide layer showed a broad absorption peak around 250–300 nm. For the Cu 2O nano-particles, the optical responsivity under an incident light with wavelength of 260–390 nm was measured about 1.38 × 10 3 A/W at 0 V bias, and the external quantum efficiency appeared about 1.0% between 200 nm and 400 nm.

Optical and Magneto-Optical Studies of Composite Materials Containing Semimagnetic Semiconductor Nanoparticles

Сomposite films containing II-VI based semiconductor nanoparticles have been prepared by different physical and chemical techniques. Non-magnetic CdS1-xSex nanoparticles were grown by melting of the semiconductor doped fine powder borosilicate glass. The composite semimagnetic semiconductor Cd1-xMnxTe based films were fabricated by embedding in SiO2 matrix with using of pulsed laser deposition technique. New chemical approach to synthesis of Cd1-xMnxS nanoparticles in polymer matrix has been proposed. The optical absorption edge for CdS1-xSex , Cd1-xMnxTe nanoparticles and exciton structure in the spectrum of Cd1-xMnxS nanoparticles shifted to the higher-energy side compared to those for bulk crystals due to the quantum confinement effect. Magneto-optical Faraday effect for non-magnetic semiconductor nanoparticles in glass demonstrates only small changes as compared with that of bulk semiconductors. The revealed peculiarities in spectral and magnetic field dependences of the Faraday rotation for the studied semimagnetic semiconductor composite films can be attributed to the influence of dimensionality on spin exchange parameters for such kind of nanostructures.

Magnetic response of NiFe 2O 4 nanoparticles in polymer matrix

We report the magnetic properties of magnetic nano-composite, consisting of different quantity of NiFe 2O 4 nanoparticles in polymer matrix. The nanoparticles exhibited a typical magnetization blocking, which is sensitive on the variation of magnetic field, mode of zero-field-cooled/field-cooled experiments and particle quantity in the matrix. The samples with lower particle quantity showed an upturn of magnetization down to 5 K, whereas the blocking of magnetization dominates at lower temperatures as the particle quantity increases in the polymer. We examine such magnetic behaviour in terms of the competitive magnetic ordering between core and surface spins of nanoparticles, taking into account the effect of inter-particle (dipole–dipole) interactions on nanoparticle magnetic dynamics.

Preparation, microstructure, and property characterizations of fluorinated polyimide–organosilicate hybrids

Synthesis of organosilicate (orgSiO 2) via sol-gel process utilizing tetraethoxysilane (TEOS) and diethoxydimethylsilane (DEDMS) as precursors was carried out in this work. Various amounts of orgSiO 2 were blended with fluorinated poly(amic acid) (PAA) to form the PAA–orgSiO 2 precursors and the fluorinated polyimide (PI)–orgSiO 2 (i.e., the HR1) thin-film hybrids were prepared via spin coating and curing treatments. The PI–orgSiO 2–AP (i.e., the HR2) hybrids were also prepared by using the PAA–orgSiO 2 precursors containing the amine silane coupling agent, the 3-aminopropyltriethoxysilane (APTEOS). The effects of APTEOS on promoting the crosslinking between organic and inorganic components as well as the network formation were investigated. Fourier-transform infrared spectroscopy (FTIR) showed that the orgSiO 2 particles indeed formed in the hybrids due to the emergence of absorption bands corresponding to Si O Si and O Si O bonds. Nuclear magnetic resonance (NMR) analyses revealed that the Q 4 units or, the four bridging bond units, dominate the structure of orgSiO 2. Thermal analysis indicated that the implantation of orgSiO 2 in PI matrix may effectively improve the thermal stability of hybrids. Transmission electron microscopy (TEM) revealed the formation of nano-scale orgSiO 2 particles in both hybrids and the sizes of orgSiO 2 are relating to the Si content. In HR1 hybrids, the particles obviously coarsened when Si content was high while, in HR2 hybrids, the addition of APTEOS effectively suppressed the phase separation and the ultrafine orgSiO 2 particles as small as 5 nm could be achieved in the sample with high Si content. Dielectric measurements showed that the lowest values of dielectric constants are 2.40 and 2.20 for HR1 hybrid at intermediate Si content = 0.4 mol and HR2 hybrid with the highest Si content = 0.8 mol, respectively. The suppression of dielectric constants was attributed to the absence of polar Si OH and Si H 2O functional groups as well as the completion of hydrolysis in the hybrids. Formation of silica xerogels in the hybrids should be another cause of dielectric constant decrement, as indicated by the porosity calculation. Experimental results implied that the control of orgSiO 2 size to imply the closed-form silica structure is essential to the low-dielectric constant properties of hybrids. Leakage current density measurement illustrated that no deterioration effect occurs due to the addition of orgSiO 2 nanoparticles in polymeric matrix and satisfactory electrical properties are preserved for the hybrids for advanced low-dielectric applications.

Enabling controlled dispersion in polyethylene nanocomposites using small‐angle scattering

AbstractIn this article, we present some key results that demonstrate the useful application of light scattering to characterize the dispersion of nanoparticles in polymer matrix, using polyethylene nanocomposite as an example. Our results show that the dispersions of nanoparticles in polyethylene nanocomposite, that influence the thermomechanical properties of polyethylene nanocomposites, can be characterized by using small angle light scattering. This proposition is motivated by recent synthetic and morphological characterization progress towards achieving ideally dispersed polyethylene nanocomposites. Our results are significant because it is shown that using light, size and shape features that correlate well with the scanning electron microscopy observations of nanoparticle dispersion can be obtained using our unique vertical light scattering set‐up. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers

Plasmonic properties of silver in polymer

In the present research silver nanoparticles were produced by e-beam evaporation of metal on polymer-modified silica substrate at room temperature (20 °C) and elevated temperature (80 °C). Modification of the silica substrate was done by different weight concentration polymer (PMMA/PS) blends formed from the polymer solutions by spin coating. The silver layer thickness varied from 1 nm to 10 nm. Silver nanoparticles in polymer matrix were characterized by XRD, AFM and UV–vis spectrometry. The crystalline silver nanoparticles showed surface plasmon resonance (SPR) with absorption maximum at 420–550 nm that was dependent on the silver layer thickness, PMMA and PS weight concentration in polymer blends and substrate temperature during vacuum deposition. The silver nanoparticles in polymer with selective light properties resulting from the controlled SPR shifting to the UV–vis wavelength region were produced.

Graft Polymerization of p-Vinylphenylsulfonylhydrazide onto Nano-Silica and its Effect on Dispersion of the Nanoparticles in Polymer Matrix

To promote dispersion of nano-silica in polypropylene (PP), a polymerizable foaming agent p-vinylphenylsulfonylhydrazide was synthesized and grafted onto the nanoparticles via free-radical polymerization. The results of thermogravimetric analysis (TGA) showed that the sulfonyl hydrazide groups of poly(p-vinylphenylsulfonylhydrazide) acquired the desired thermal decomposition ability, which might be related to their internal oxidation-reduction. Electron microscopy observation indicated that the grafted nanoparticles exhibit greatly improved dispersion in PP owing to the fact that the sulfonyl hydrazine groups on the grafted polymer inside the agglomerates decomposed like blowing agent to form polymer bubbles, leading to rapid inflation of the surrounding matrix that pulled apart the agglomerated nanoparticles during melting mixing.

Growth of Monodisperse Silver Nanoparticles in Polymer Matrix by Spray Pyrolysis

Silver nanoparticles were simply prepared by spray pyrolysis of aqueous solutions of AgNO 3 , and dextran or Poly (vinylalcohol) (PVA) without any reducing agent. Monodisperse particles well-organized in polymer matrix were obtained above a certain critical ratio of polymer to silver nitrate, usually around 1, and below decomposition temperatures of the polymer. Otherwise, the silver particles grew polydisperse due to the imperfect confinement of the polymer. Their shapes varied from facetted with dextran to spherical with PVA, depending on the interaction of silver and the polymer. The confinement increased and thus the critical ratio decreased by increasing the molecular weight of the polymer and replacing PVA by dextran. Above the ratio, the particles got smaller with the concentration of dextran, while their size did not vary in PVA due to its configuration.

Processing and properties of composite magnetic powders containing Co nanoparticles in polymeric matrix

Polymeric matrix ferromagnetic nanocomposites, containing Co nanocrystallites were processed by an innovative fabrication method using frontal polymerisation of cobalt acrylamid complex (CoAAm), followed by further thermolysis. The products of thermolysis were in a form of irregular powder particles having broad range of size distribution, from 10 μm up to 300 μm. The powder particles contain nanocrystallites of Co having the mean 12–15 nm, depending on the thermolysis temperature. The particles are randomly distributed and their size and agglomeration can be controlled by the processing variables. The hysteresis loops recorded for materials processed at 873 and 1073 K, respectively proved that the coercivity depends on the processing temperature and very slightly on the measurement temperature. According to the commonly approved classification the coercivity of the composite material processed at temperatures 873 and 1073 K can be regarded as magnetically soft and hard, respectively.

Preparation of nano-ZnO/PMMA composite particles via grafting of the copolymer onto the surface of zinc oxide nanoparticles

The grafting of polymers onto the surface of zinc oxide nanoparticles and radical copolymerization of methyl methacrylate (MMA) and methacrylic acid (MAA) were investigated. The copolymer chains encapsulating nanoparticles were anchored onto the surface of nano-ZnO through reactions of carboxyl groups with ZnO. Grafting percentage and grafting efficiency of composite particles were investigated by employing thermogravimetric analysis (TGA). FT-IR and 13C NMR showed that there existed a strong interaction at the interface of nano-ZnO and copolymer, which implied that the copolymer chains were grafted onto the surface of ZnO nanoparticles. Nano-ZnO being encapsulated by copolymer was confirmed by using transmission electron microscopy (TEM). Additionally, TGA plots showed that the presence of ZnO nanoparticles improved the thermal stability of copolymer to a certain extent. Another important finding is the copolymerization and grafting reaction did not alter the crystalline structure of the ZnO nanoparticles according to the X-ray diffraction patterns. It can also be seen from scanning electron microscope (SEM) that grafted polymer chains on nanoparticles interfere with the aggregation of ZnO nanoparticles in polymer matrix and improve their compatibility with the polymeric matrix.

Tribological and corrosion behaviors of Al 2O 3/polymer nanocomposite coatings

In this paper, the tribological and electrochemical corrosion properties of Al 2O 3/polymer nanocomposite coatings were studied by using micro-hardness test, single-pass scratch test, abrasive wear test, and finally electrochemical technique such as potentiodynamic polarization measurement. The coatings containing Al 2O 3 nanoparticles showed improvement in scratch and abrasive resistance compared with that of polymer coating. The improvement in scratch and abrasive resistance is attributed to the dispersion hardening of Al 2O 3 nanoparticles in polymer coatings. Corrosion test results showed that the embedded Al 2O 3 nanoparticles in polymer matrix do not sacrifice the corrosion resistance of the polymer itself.

Formation of metal-containing nanoparticles in polymer matrix. Computer simulation of clusterization kinetics during the solid-phase thermal decomposition of metal-containing precursors

Formation of metal-containing nanoparticles in polymer matrix. Computer simulation of clusterization kinetics during the solid-phase thermal decomposition of metal-containing precursors

Formation of metal-containing nanoparticles in polymer matrix. Computer simulation of clusterization kinetics during the solid-phase thermal decomposition of metal-containing precursors

Formation of metal-containing nanoparticles in polymer matrix. Computer simulation of clusterization kinetics during the solid-phase thermal decomposition of metal-containing precursors

Formation of metal-containing nanoparticles in polymer matrix. Computer simulation of clusterization kinetics during the solid-phase thermal decomposition of metal-containing precursors

The scheme of computer simulation of the dynamics of the formation of metal-containing clusters in a polymer matrix during the solid-phase thermolysis of corresponding precursors is developed. The kinetics of particle nucleation and growth is studied within the framework of the model of diffusion-limited aggregation by the combined marching and Monte Carlo methods. Polymer media with different structural organization such as isotropic (globular) and anisotropic (layered and fibrillar) media are considered. Deterministic algorithms of the model are the decomposition of reactive metal-containing groups of a polymer, solid-phase diffusion of particles, and cluster dissociation. The proposed scheme makes it possible to visualize the process of cluster formation.

Generation and Formation of Gold Nanoparticles with Spatial Control by Two-Photon Femtosecond Laser Interference

AbstractA simple strategy for generating and distributing metallic nanoparticles in polymer matrix with a spatial control in micrometer/nanometer scale has been proposed and successfully demonstrated by combination of two-photon photoreduction and femtosecond laser interference technique. The simultaneous spatially controlling generation and organization of metallic nanopartciles were controllable by designing interference patterns and varying laser intensity and exposure time. This strategy provides a simple and rapid approach for creating templates with designed spatial distribution of the nanoparticles, which is favorable for current microelectronics technology. This method also can be utilized in developing mass production processes for future nanodevices.

Synthesis of cobalt disulfide nanoparticles in polymer matrix

Amorphous rod-like and needle-like nanoparticles of cobalt disulfide were prepared by the reaction of CoCl 2·6H 2O with thiourea in the presence of some hydrazine in aqueous solution. The reaction was undertaken in an open reflux system at a relatively low temperature. Polycrystalline cobalt disulfide nanorods were obtained by a similar reaction in an alcohol/water mixed solution. The products were characterized by Fourier transform infrared spectrometer (FTIR), X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). The effects of solvent, temperature and time of the reaction on the formation of cobalt disulfide nanocrystalline were discussed. It was found that hydrazine played an important role in shaping rod- or needle-like nanoparticles, and the reflux temperature and time mainly influenced the crystallization of nanoparticles. In addition, the microwave (wavelength λ=3 cm) absorption property of this nanocomposite at room temperature was also investigated.