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Full-Text Articles in Nanoscience and Nanotechnology

Facile Preparation Of Quantum Cutting Gdf3 : Eu3+ Nanoparticles From Ionic Liquids, Chantal Lorbeer, Joanna Cybinska, Anja V. Mudring Jan 2010

Facile Preparation Of Quantum Cutting Gdf3 : Eu3+ Nanoparticles From Ionic Liquids, Chantal Lorbeer, Joanna Cybinska, Anja V. Mudring

Anja V. Mudring

Microwave reaction of Ln(OAc)3·xH2O, Ln = Gd, Eu; OAc = acetate) with and in the ionic liquid [C4mim][BF4] (C4mim = 1-butyl-3-methylimidazolium) allows the fast and efficient synthesis of small, uniform, oxygen-free lanthanide nanofluorides with excellent photophysical behaviour. For GdF3 : Eu3+ nanoparticles a quantum efficiency of up to 145% was determined.


Easy Access To Ultra Long-Time Stable, Luminescent Europium(Ii) Fluoride Nanoparticles In Ionic Liquids, Nina Von Prondzinski, Joanna Cybinska, Anja V. Mudring Jan 2010

Easy Access To Ultra Long-Time Stable, Luminescent Europium(Ii) Fluoride Nanoparticles In Ionic Liquids, Nina Von Prondzinski, Joanna Cybinska, Anja V. Mudring

Anja V. Mudring

Physical vapour deposition into ionic liquids allows for the first time the synthesis of a reduced lanthanide halide on the nanoscale. The obtained EuF2 nanoparticles show a bright blue luminescence and form long-time stable-colloidal solutions in the ionic liquids.


Molecular Dynamics Simulation Of Poly(Ethylene Terephthalate) Oligomers, David Keffer, Qifei Wang, Simioan Petrovan, J. Thomas Dec 2009

Molecular Dynamics Simulation Of Poly(Ethylene Terephthalate) Oligomers, David Keffer, Qifei Wang, Simioan Petrovan, J. Thomas

David Keffer

Molecular dynamics simulations of poly(ethylene terephthalate) (PET) oligomers are performed in the isobaric−isothermal (NpT) ensemble at a state point typical of a finishing reactor. The oligomer size ranges from 1 to 10 repeat units. We report thermodynamic properties (density, potential energy, enthalpy, heat capacity, isothermal compressibility, and thermal expansivity), transport properties (self-diffusivity, zero-shear-rate viscosity, thermal conductivity), and structural properties (pair correlation functions, hydrogen bonding network, chain radius of gyration, chain end-to-end distance) as a function of oligomer size. We compare the results with existing molecular-level theories and experimental data. Scaling exponents as a function of degree of polymerization ...


Molecular Simulations Of H2 Adsorption In Metal-Porphyrin Frameworks (Mpfs): A Potential New Material Evaluation, Ruichang Xiong, David Keffer Dec 2009

Molecular Simulations Of H2 Adsorption In Metal-Porphyrin Frameworks (Mpfs): A Potential New Material Evaluation, Ruichang Xiong, David Keffer

David Keffer

Path integral grand canonical Monte Carlo (PI-GCMC) simulations using standard force fields are carried out to calculate the adsorption of H2 in five metal-porphyrin frameworks (MPFs), a new class of metal organic framework (MOF)-type materials. These simulations are performed at 77 K and room temperature (300 K). The adsorption isotherms of H2 in IRMOF-1 and IRMOF-10 are also calculated as a comparison. All calculations indicate that all MPFs adsorbed a higher weight fraction of H2 than both IRMOF-1 and IRMOF-10, with one exception (MPF-2). The gravimetric hydrogen capacities are still well short of practical goals. The MPFs provide additional ...


Molecular Simulation Images, David Keffer Dec 2009

Molecular Simulation Images, David Keffer

David Keffer

These animations and interactive structures are created from various molecular dynamics simulations and quantum calculations. In order to view the interactive structures, you need the free "Chime" Plug-in. In order to view the movie files (in avi format), you will require the following codec: TSCC codec. This work has been supported by DOE BES, AFOSR, NSF and ACS PRF.


Effective Potentials Between Nanoparticles In Suspension, Gary Grest, Qifei Wang, Pieter In't Veld, David Keffer Dec 2009

Effective Potentials Between Nanoparticles In Suspension, Gary Grest, Qifei Wang, Pieter In't Veld, David Keffer

David Keffer

Results of molecular dynamics simulations are presented for the pair distribution function between nanoparticles in an explicit solvent as a function of nanoparticle diameter and interaction strength between the nanoparticle and solvent. The effect of including the solvent explicitly is demonstrated by comparing the pair distribution function of nanoparticles to that in an implicit solvent. The nanoparticles are modeled as a uniform distribution of Lennard-Jones particles, while the solvent is represented by standard Lennard-Jones particles. The diameter of the nanoparticle is varied from 10 to 25 times that of the solvent for a range of nanoparticle volume fractions. As the ...


Dynamics Of Individual Molecules Of Linear Polyethylene Liquids Under Shear: Atomistic Simulation And Comparison With A Free-Draining Bead-Rod Chain, David Keffer, J. Kim, B. Edwards, B. Khomami Dec 2009

Dynamics Of Individual Molecules Of Linear Polyethylene Liquids Under Shear: Atomistic Simulation And Comparison With A Free-Draining Bead-Rod Chain, David Keffer, J. Kim, B. Edwards, B. Khomami

David Keffer

Nonequilibrium molecular dynamics (NEMD) simulations of a dense liquid composed of linear polyethylene chains were performed to investigate the chain dynamics under shear. Brownian dynamics (BD) simulations of a freely jointed chain with equivalent contour length were also performed in the case of a dilute solution. This allowed for a close comparison of the chain dynamics of similar molecules for two very different types of liquids. Both simulations exhibited a distribution of the end-to-end vector, |Rete|, with Gaussian behavior at low Weissenberg number (Wi). At high Wi, the NEMD distribution was bimodal, with two peaks associated with rotation and ...