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Hybrid Particles (hybrid + particle)
Selected AbstractsPreparation and Characterization of Uniformly Sized Sub-micrometer Spherical Silica/Organic Polymer Hybrid ParticlesADVANCED ENGINEERING MATERIALS, Issue 9 2003X.-s. Xing Hybrid particles with a core-shell structure, consisting of a silica core and a polyvinyl alcohol (PVA) shell, (see Figure for an SEM image of a particle material of this type), were fabricated via a two-step sol-gel process. The PVA molecular chains are probably physically adsorbed onto the surface of silica cores by hydrogen bonds and van der Waals forces. [source] Nanoparticle Electroluminescence: Controlling Emission Color Through Förster Resonance Energy Transfer in Hybrid ParticlesADVANCED FUNCTIONAL MATERIALS, Issue 22 2009Christopher F. Huebner Abstract Electroluminescent (EL) polymers are attractive for developing all-organic light-emitting devices (OLEDs) due to the potential advantages that polymeric systems may offer in the large-scale manufacturing of electronics. Nonetheless, many of these EL , -conjugated polymers are inherently insoluble in the solvents employed in the intended solution-based manufacturing processes. One such polymer is poly(2,5-dioctyl-1,4-phenylenevinylene) (POPPV), where the inherent lack of solubility of POPPV in organic solvents has frustrated its widespread application in devices and no OLEDs have been presented that exploit its electroluminescence characteristics. In this effort, a unique strategy is presented for the preparation of hybrid nanoparticles composed of POPPV, a green emitter (,em,=,505,nm) and poly(9,9-di- n -octylfluorenyl-2,7-diyl) (PFO), a blue emitter (,em,=,417,nm). The aqueous-based nanoparticle dispersion composed of these hybrid particles is stable to aggregate and can be employed in the construction of OLEDs. The color characteristics of the electroluminescence for the devices can be tuned by exploiting the Förster resonance energy transfer between the polymers within a particle, while suppressing energy transfer between the particles. These aqueous-based nanoparticle dispersions are amenable to being printed into devices through high-throughput manufacturing techniques, for example, roll-to-roll printing. [source] Metal Nanoparticle/Polymer Hybrid Particles: The Catalytic Activity of Metal Nanoparticles Formed on the Surface of Polymer Particles by UV-IrradiationMACROMOLECULAR SYMPOSIA, Issue 1 2009Toshiyuki Tamai Abstract Summary: Polymer particles decorated with metal nanoparticles were prepared by UV-irradiation of polystyrene particles incorporating polymethylphenylsilane (PS/PMPS) and P[S- co -NIPAM]/PMPS particles (NIPAM: N-isopropyl acrylamide) in the presence of metal salts. The metal nanoparticle/polymer hybrid particles were used as a catalyst for the reduction of 4-nitrophenol with NaBH4. The Pd- and Ag-P(S- co -NIPAM)/PMPS hybrid particles had larger metal nanoparticles and the lower catalytic activity than those of Pd- and Ag-PS/PMPS, respectively. The surface functional group of the polymer particles affected the formation of the metal nanoparticles and their catalytic activity. [source] Preparation and Characterization of Uniformly Sized Sub-micrometer Spherical Silica/Organic Polymer Hybrid ParticlesADVANCED ENGINEERING MATERIALS, Issue 9 2003X.-s. Xing Hybrid particles with a core-shell structure, consisting of a silica core and a polyvinyl alcohol (PVA) shell, (see Figure for an SEM image of a particle material of this type), were fabricated via a two-step sol-gel process. The PVA molecular chains are probably physically adsorbed onto the surface of silica cores by hydrogen bonds and van der Waals forces. [source] Nanoparticle Electroluminescence: Controlling Emission Color Through Förster Resonance Energy Transfer in Hybrid ParticlesADVANCED FUNCTIONAL MATERIALS, Issue 22 2009Christopher F. Huebner Abstract Electroluminescent (EL) polymers are attractive for developing all-organic light-emitting devices (OLEDs) due to the potential advantages that polymeric systems may offer in the large-scale manufacturing of electronics. Nonetheless, many of these EL , -conjugated polymers are inherently insoluble in the solvents employed in the intended solution-based manufacturing processes. One such polymer is poly(2,5-dioctyl-1,4-phenylenevinylene) (POPPV), where the inherent lack of solubility of POPPV in organic solvents has frustrated its widespread application in devices and no OLEDs have been presented that exploit its electroluminescence characteristics. In this effort, a unique strategy is presented for the preparation of hybrid nanoparticles composed of POPPV, a green emitter (,em,=,505,nm) and poly(9,9-di- n -octylfluorenyl-2,7-diyl) (PFO), a blue emitter (,em,=,417,nm). The aqueous-based nanoparticle dispersion composed of these hybrid particles is stable to aggregate and can be employed in the construction of OLEDs. The color characteristics of the electroluminescence for the devices can be tuned by exploiting the Förster resonance energy transfer between the polymers within a particle, while suppressing energy transfer between the particles. These aqueous-based nanoparticle dispersions are amenable to being printed into devices through high-throughput manufacturing techniques, for example, roll-to-roll printing. [source] Grafting polymer chains bearing an N -succinimidyl activated ester end-group onto primary amine-coated silica particles and application of a simple, one-step approach via nitroxide-mediated controlled/living free-radical polymerizationJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2010Julien Parvole Abstract In a first part, the alkoxyamine initiator derived from BlocBuilder® based on the nitroxide SG1 and bearing an N -succinimidyl ester function was used to synthesize a variety of well-defined polymers with the activated ester group at the ,-end. The grafting of those polymer chains onto primary-amine functionalized Stöber silica particles was performed in soft conditions at room temperature and was studied as a function of the polymer chain length, the type of solvent, and the concentrations of both polymer and amine. Polymer grafting densities were mainly in the 0.1,0.2 chain nm,2 range. To increase the grafting density in simple experimental conditions, a direct one-step method was then proposed: the primary-amine modified silica, the N -succinimidyl ester functionalized alkoxyamine, and the monomer were all introduced into the reaction medium at once. This technique allowed grafting and chain growth to take place simultaneously at the polymerization temperature (i.e., 120 °C for styrene), in a single step, and produced hybrid particles with very high grafting density, up to 0.9 chain nm,2, and long polymer chains. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 173,185, 2010 [source] Synthesis of raspberry-like silica/polystyrene/silica multilayer hybrid particles via miniemulsion polymerizationJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 6 2007Xiaoguang Qiao Abstract Organic,inorganic hybrid particles have many potential applications, but almost all research has been focused on hybrid particles with one kind of inorganic nanoparticle. This article presents a novel and facile preparation approach for raspberry-like silica/polystyrene/silica multilayer hybrid particles via miniemulsion polymerization. In this method, larger, surface-modified silica particles are first dispersed into monomer droplets to form a miniemulsion, and then raspberry-like silica/polystyrene/silica multilayer hybrid particles are directly obtained when miniemulsion polymerization is performed in the presence of smaller, unmodified silica particles with 4-vinylpyridine as an auxiliary monomer. Influential parameters such as the amount of 4-vinylpyridine, the surfactant concentration, and the pH value of the system have been investigated. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1028,1037, 2007 [source] The application of novel 1.7 ,m ethylene bridged hybrid particles for hydrophilic interaction chromatographyJOURNAL OF SEPARATION SCIENCE, JSS, Issue 9 2008Eric S. Grumbach Abstract An un-derivatized 1.7 ,m ethylene bridged hybrid (BEH) particle was evaluated for its utility in retaining polar species in hydrophilic interaction chromatography (HILIC), and was compared to a 3 ,m un-derivatized silica material. Retentivity as a function of mobile phase pH, polar modifier and ACN content was examined. Also, the efficiency of the two particle substrates was compared by plotting HETP vs. linear velocity. Improved chemical resistance of the un-derivatized BEH particle was compared to un-derivatized silica at pH 5, demonstrating no performance deterioration over the course of 2000 injections for the BEH particle, while the silica particle deteriorated rapidly after 800 injections. Lastly, ESI-MS sensitivity as a function of particle size and separation mode was demonstrated. A 2.2 to 4.7-times higher ESI-MS response was observed on the 1.7 ,m particle compared to the 3 ,m particle, whereas a 5.6 to 8.8-times higher ESI-MS response was observed using HILIC as when compared to traditional RP chromatography. [source] Poly(ethylene glycol) Surface Coated Magnetic ParticlesMACROMOLECULAR RAPID COMMUNICATIONS, Issue 18 2005Christophe Flesch Abstract Summary: A methacrylate-functionalized poly(ethylene glycol) macromonomer was copolymerized at the surface of methacrylate-derivatized maghemite nanoparticles. After silylation of the magnetic core with methacryloxypropyltrimethoxysilane, two grafting procedures based on either a direct copolymerization reaction in water or an inverse emulsion polymerization were compared. A direct copolymerization led to low polymer surface amounts, whereas an inverse emulsion process allowed nanocomposite particles containing up to 90 wt.-% polymer to be obtained. TEM picture of maghemite-PEG hybrid particles. [source] Metal Nanoparticle/Polymer Hybrid Particles: The Catalytic Activity of Metal Nanoparticles Formed on the Surface of Polymer Particles by UV-IrradiationMACROMOLECULAR SYMPOSIA, Issue 1 2009Toshiyuki Tamai Abstract Summary: Polymer particles decorated with metal nanoparticles were prepared by UV-irradiation of polystyrene particles incorporating polymethylphenylsilane (PS/PMPS) and P[S- co -NIPAM]/PMPS particles (NIPAM: N-isopropyl acrylamide) in the presence of metal salts. The metal nanoparticle/polymer hybrid particles were used as a catalyst for the reduction of 4-nitrophenol with NaBH4. The Pd- and Ag-P(S- co -NIPAM)/PMPS hybrid particles had larger metal nanoparticles and the lower catalytic activity than those of Pd- and Ag-PS/PMPS, respectively. The surface functional group of the polymer particles affected the formation of the metal nanoparticles and their catalytic activity. [source] Composite aqueous microgels: an overview of recent advances in synthesis, characterization and applicationPOLYMER INTERNATIONAL, Issue 3 2007Andrij Z Pich Abstract In the last decade there has been a steady increase in the number of publications describing the synthesis, characterization and applications of hybrid particles. Colloidal aqueous microgels form an important subdivision of polymer colloids used for the deposition of different functional materials. Due to their numerous attractive properties, microgel particles have been used as templates for the synthesis, storage and transportation of nanostructured materials. This paper reviews the important developments in the area of composite microgels over the last decade, and is limited to microgel particles operating in aqueous media. The patent literature is not included in the review. Different synthetic approaches as well as some properties and applications of composite microgels are discussed. Copyright © 2006 Society of Chemical Industry [source] | ||||||||||||||||||||||