Nanoparticle Composites (nanoparticle + composite)

Distribution by Scientific Domains


Selected Abstracts


Preparation of Functionalized Polysilsesquioxane and Polysilsesquioxane-Metal Nanoparticle Composite Spheres,

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 15 2006
Young Baek Kim
Abstract Summary: Network polysilsesquioxane spheres made solely of poly(vinylsilsesquioxane) (PVSQ) and poly(3-mercaptopropylsilsesquioxane) (PMPSQ) were prepared from heterogeneous mixtures of triethylamine (TEA), water, and either vinyltrimethoxysilane (VTMS), or 3-mercaptopropyltrimethoxysilane (MPTMS). The microscopic, macroscopic observations, and the relationship between the diameters of spheres and the amount of each ingredient in the reaction system, showed that spheres formed via a mechanism similar to emulsion polymerization and suspension polymerization, depending on the reaction conditions. Diameters of spheres could be controlled from tens of nanometers to a few micrometers by adjusting the amounts of TEA, water, and a surfactant. Heating aqueous solutions of metal ions with these spheres produced polysilsesquioxanes (PSQ)-metal nanoparticle composite spheres. The spheres prepared in this study were characterized by scanning electron microscopy, transmission electron microscopy, solid state NMR spectroscopy, IR spectroscopy, elemental analysis, and differential thermal analysis. These spheres would be useful in recovering metals from their ionic solutions and probes after chemical modifications. An image of the spheres of poly(vinylsilsesquioxane)-gold nanoparticle composite. [source]


Sonochemical synthesis and characterization of ZnO nanorod/Ag nanoparticle composites

CRYSTAL RESEARCH AND TECHNOLOGY, Issue 11 2009
Fei Li
Abstract A simple sonochemical route for the synthesis of Ag nanoparticles on ZnO nanorods is reported. Ultrasonic irradiation of a mixture of ZnO nanorods, Ag(NH3)2+, and formaldehyde in an aqueous medium yields ZnO nanorod/Ag nanoparticle composites. The powder X-ray diffraction of the ZnO/Ag composites shows additional diffraction peaks corresponding to the face-center-cubic structured Ag crystalline, apart from the signals from the ZnO nanorods. Scanning electron microscopy and transmission electron microscopy images of the ZnO/Ag composites reveal that the ZnO nanorods are coated with Ag nanoparticles with a mean size of several tens nanometer. The absorption band of ZnO/Ag composites is distinctly broadened and red-shifted, indicating the strong interfacial interaction between ZnO nanorods and Ag nanoparticles. This sonochemical method is simple, mild and readily scaled up, affording a simple way for synthesis of other composites. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Controlled Assembly of Protein,Nanoparticle Composites through Protein Surface Recognition,

ADVANCED MATERIALS, Issue 5 2005
S. Srivastava
Controlled assembly of protein,nanoparticle composites through complementary protein surface recognition is demonstrated. Interaction of an unstable protein (chymotrypsin) with a gold nanoparticle results in close interparticle spacing, while a stable protein (cytochrome,C) that retains its structure upon binding produces a hybrid material with a larger interparticle distance (see Figure). [source]


SHG from bulk and surface of nanoparticle composites

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2005
W. Luis Mochán
The cover picture of this issue of physica status solidi (c) has been taken from the article [1]. [source]


Synthesis and characterization of polyaniline derivative and silver nanoparticle composites

POLYMER INTERNATIONAL, Issue 10 2008
Gururaj M Neelgund
Abstract BACKGROUND: There has been a recent surge of interest in the synthesis and applications of electroactive polymers with incorporated metal nanoparticles. These hybrid systems are expected to display synergistic properties between the conjugated polymers and the metal nanoparticles, making them potential candidates for applications in sensors and electronic devices. RESULTS: Composites of polyaniline derivatives,polyaniline, poly(2,5-dimethoxyaniline) and poly(aniline-2,5-dimethoxyaniline),and silver nanoparticles were prepared through simultaneous polymerization of aniline derivative and reduction of AgNO3 in the presence of poly(styrene sulfonic acid) (PSS). We used AgNO3 as one of the initial components (1) to form the silver nanoparticles and (2) as an oxidizing agent for initiation of the polymerization reaction. UV-visible spectra of the synthesized nanocomposites reveal the synchronized formation of silver nanoparticles and polymer matrix. The morphology of the silver nanoparticles and degree of their dispersion in the nanocomposites were characterized by transmission electron microscopy. Thermogravimetric analysis and differential scanning calorimetry results indicate an enhancement of the thermal stability of the nanocomposites compared to the pure polymers. The electrical conductivity of the nanocomposites is in the range 10,4 to 10,2 S cm,1. CONCLUSION: A single-step process for the synthesis of silver nanoparticle,polyaniline derivative nanocomposites doped with PSS has been demonstrated. The approach in which silver nanoparticles are formed simultaneously during the polymerization process results in a good dispersion of the nanoparticles in the conductive polymer matrix. Copyright © 2008 Society of Chemical Industry [source]


Role of Capping Ligands on the Nanoparticles in the Modulation of Properties of a Hybrid Matrix of Nanoparticles in a 2D Film and in a Supramolecular Organogel

CHEMISTRY - A EUROPEAN JOURNAL, Issue 36 2009
Asish Pal Dr.
Abstract We incorporate various gold nanoparticles (AuNPs) capped with different ligands in two-dimensional films and three-dimensional aggregates derived from N -stearoyl- L -alanine and N -lauroyl- L -alanine, respectively. The assemblies of N -stearoyl- L -alanine afforded stable films at the air,water interface. More compact assemblies were formed upon incorporation of AuNPs in the air,water interface of N -stearoyl- L -alanine. We then examined the effects of incorporation of various AuNPs functionalized with different capping ligands in three-dimensional assemblies of N -lauroyl- L -alanine, a compound that formed a gel in hydrocarbons. The profound influence of nanoparticle incorporation into physical gels was evident from evaluation of various microscopic and bulk properties. The interaction of AuNPs with the gelator assembly was found to depend critically on the capping ligands protecting the Au surface of the gold nanoparticles. Transmission electron microscopy (TEM) showed a long-range directional assembly of certain AuNPs along the gel fibers. Scanning electron microscopy (SEM) images of the freeze-dried gels and nanocomposites indicate that the morphological transformation in the composite microstructures depends significantly on the capping agent of the nanoparticles. Differential scanning calorimetry (DSC) showed that gel formation from sol occurred at a lower temperature upon incorporation of AuNPs having capping ligands that were able to align and noncovalently interact with the gel fibers. Rheological studies indicate that the gel,nanoparticle composites exhibit significantly greater viscoelasticity compared to the native gel alone when the capping ligands are able to interact through interdigitation into the gelator assembly. Thus, it was possible to define a clear relationship between the materials and the molecular-level properties by means of manipulation of the information inscribed on the NP surface. [source]