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Size dependent thermal conductivity of single-walled carbon nanotubes J. Appl. Phys. 112, 013503 (2012) Inter-tube thermal conductance in carbon nanotubes arrays and bundles: Effects of contact area and pressure Appl. Phys. Lett. 100, 261908 (2012) The thermal flash technique: The inconsequential effect of contact resistance and the characterization of carbon nanotube clusters Rev. Sci. Instrum. 83, 054904 (2012) Thermal stability of wetting layer in quantum dot self-assembly J. Appl. Phys. 111, 093526 (2012) Additional information on Appl. Phys. Lett.

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Low thermal conductivity is a primary limitation in the development of energy-efficient heat transfer fluids required in many industrial applications. To overcome this limitation, a new class of heat transfer fluids is being developed by suspending nanocry stalline particles in liquids such as water or oil. The resulting “nanofluids” possess extremely high thermal conductivities compared to the liquids without dispersed nanocrystalline particles. For example, 5 volume % of nanocrystalline copper oxide particles suspended in water results in an improvement in thermal conductivity of almost 60% compared to water without nanoparticles. Excellent suspension properties are also observed, with no significant settling of nanocrystalline oxide particles occurring in stationary fluids over time periods longer than several days. Direct evaporation of Cu nano-particles into pump oil results in similar improvements in thermal conductivity compared to oxide-in-water systems, but importantly, requires far smaller concentrations of dispersed nanocrystalline powder.

Gold nanorods exhibit optical properties that are tunable with their shape, leading to sensing, imaging, and biomedical therapeutic applications. Colloidal preparations of gold nanorods impart surfactants or other species on the nanorod surfaces; a popular preparation leads to a surfactant bilayer on the surface. The specific chemistry at three distinct interfaces has roles to play in the growth and subsequent usage of these nanomaterials; these interfaces are the gold−surfactant interface, the hydrophobic surfactant bilayer, and, finally, the surfactant interface with the aqueous bulk. Each one of these interfaces provides strategies for altering nanorod properties such as stability against aggregation, toxicity, and ease of assembly. It is the solvent-accessible interface that dictates nanorod interactions with other particles, macromolecules, and living cells.

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In situ x-ray-diffraction studies of the hydriding behavior of coarse-grained and nanocrystalline palladium samples at ambient temperature are descibed. A previously observed narrowing of the miscibility gap in nanocrystalline palladium was reproduced. The present results, however, demonstrate that this change in the palladium-hydrogen phase diagram for nanocrystalline material is not related to an inability to form the hydride phase in highly disordered grain boundary regions as previously proposed. Instead, the entire volume of nanocrystalline samples was observed to transform to P-PdH upon exposure to hydrogen. This behavior indicates that the entropy and/or enthalpy of mixing for the palladiumhydrogen system differs in nanocrystalline and coarse-grained materials. Because of these changes in thermodynamic quantities, the phase boundary of the palladium-hydrogen miscibility gap is predicted to be shifted to lower temperatures for nanocrystalline samples.