R . S . Keyniton R . W . Cohn

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Using various nanomanipulating instruments, solvated polymers are simultaneously formed into fibers, adhered to solid supports, and interconnected in real-time to create suspended fiber bridges and networks of specified geometries. Fibers from 50 nm to 20 μm diameter have been drawn individually and in parallel using single tips and tip arrays. The speed(More)
Liquid gallium drops placed on thick Ag films at room temperature spontaneously form faceted nanoneedles of Ag2Ga alloy oriented nearly normal to the surface. This observation suggests that single nanoneedles can be selectively grown by drawing silver-coated microcantilevers from gallium. Needles from 25 nm to microns in diameter and up to 33 m long were(More)
We investigate the mechanical properties of cantilevered silver-gallium (Ag(2)Ga) nanowires using laser Doppler vibrometry. From measurements of the resonant frequencies and associated operating deflection shapes, we demonstrate that these Ag(2)Ga nanowires behave as ideal Euler-Bernoulli beams. Furthermore, radial asymmetries in these nanowires are(More)
A new 512 x 512 pixel phase-only spatial light modulator (SLM) has been found to deviate from being flat by several wavelengths. Also, the retardation of the SLM relative to voltage varies across the device by as much as 0.25 wavelength. The birefringence of each pixel as a function of address voltage is measured from the intensity of the SLM between(More)
The engineering of large (thickness > 100 μm) tissues requires a microvascular network to supply nutrients and remove waste. To produce microvasculature in vitro, a scaffold is required to mechanically support and stimulate endothelial cell (EC) adhesion and growth. Scaffolds for ECs are currently produced by patterning polymers or other biomaterials into(More)
No current microfabrication technique exists for producing roomtemperature, high-precision, point-to-point polymer microand submicroscale fibers in three dimensions. The purpose of this work is to characterize a novel method for fabricating interconnected threedimensional (3-D) structures of micron and sub-micron feature size. Poly(methyl methacrylate)(More)
The micro-Wilhelmy method is a well-established method of determining surface tension by measuring the force of withdrawing a tens of microns to millimeters in diameter cylindrical wire or fiber from a liquid. A comparison of insertion force to retraction force can also be used to determine the contact angle with the fiber. Given the limited availability of(More)
Loose graphene sheets, one to a few atomic layers thick, are often observed on freshly cleaved HOPG surfaces. A straightforward technique using electrostatic attraction is demonstrated to transfer these graphene sheets to a selected substrate. Sheets from one to 22 layers thick have been transferred by this method. One sheet after initial deposition is(More)
We have performed scanning gate microscopy (SGM) on graphene field effect transistors (GFET) using a biased metallic nanowire coated with a dielectric layer as a contact mode tip and local top gate. Electrical transport through graphene at various back gate voltages is monitored as a function of tip voltage and tip position. Near the Dirac point, the(More)
Jian Chen,†,| Apparao M. Rao,† Sergei Lyuksyutov,‡ Mikhail E. Itkis,†,⊥ Mark. A. Hamon,†,⊥ Hui Hu,†,⊥ Robert W. Cohn,‡ Peter C. Eklund,† Daniel T. Colbert,§ Richard E. Smalley,§ and Robert C. Haddon*,†,⊥ Departments of Chemistry and Physics, AdVanced Carbon Materials Center, UniVersity of Kentucky, Lexington, Kentucky 40506-0055, Carbon Solutions, Inc, A(More)