Bulletin of the American Physical Society
65th Annual Meeting of the APS Division of Fluid Dynamics
Volume 57, Number 17
Sunday–Tuesday, November 18–20, 2012; San Diego, California
Session A30: Nanofluids: Experiments |
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Chair: Alessandro Siria, University of Lyon Room: 33A |
Sunday, November 18, 2012 8:00AM - 8:13AM |
A30.00001: Fluid-Induced Nanomechanical Fluctuations of an Elastic Membrane Charles Lissandrello, Victor Yakhot, Kamil L. Ekinci We study the mechanical fluctuations of an elastic membrane induced by collisions with surrounding gas molecules. The system under study is a mm$^2$ 200-nm-thick silicon nitride membrane under tension. The membrane has well-separated resonant modes, which are accurately described by elasticity theory. The membrane is held in a vacuum chamber, and the frequency spectrum of its fluctuations are monitored, as a function of gas pressure, using a sensitive heterodyne interferometer. Our measurements, combined with the fluctuation-dissipation theorem, provide insight into solid-fluid interactions at the nanoscale. [Preview Abstract] |
Sunday, November 18, 2012 8:13AM - 8:26AM |
A30.00002: Focused electrojetting for nanoscale 3-D fabrication Minhee Lee, Ho-Young Kim Although extreme miniaturization of components in integrated circuits and biochemical chips has driven the development of various nanofabrication technologies, three-dimensional fabrication of nanoscale objects is still in its infancy. Here we propose a novel method to fabricate a free-standing nanowall by the line-by-line deposition of electrospun polymer nanofibers. We show that the electrified nanojet, which tends to get unstable as traveling in free space due to the Coulombic repulsion, can be stably focused onto a narrow line of metal electrode. On the conducting line, the polymer nanojet is spontaneously folded successively to form a wall-like structure. We rationalize the period of spontaneous folding by balancing the tension in the polymer fiber with the electrostatic interaction of the fiber with the metal ground. This novel fabrication scheme can be applied for the development of three-dimensional bioscaffolds, nanofilters and nanorobots. [Preview Abstract] |
Sunday, November 18, 2012 8:26AM - 8:39AM |
A30.00003: In situ SAXS measurement of nanoparticles filtered with a thin film of macromolecules F.J. de Jong, A. Buffet, G. Herzog, M. Schwartzkopf, J. Perlich, V. Koerstgens, M. Mecklenburg, T. Schnoor, P. Mueller-Buschbaum, S. Roth, K. Schulte, M. Schlueter Nanofluidics is connected to many different domains in technology, biology and medicine [1]. Exploring new science using controlled regular nanostructures is by far the most significant benefit of nanofluidics [2]. Macromolecules typically serve as well-ordered nanostructures that can be used for filtering purposes. Especially sieving and filtering of nanoparticles is of big interest in medicine [3]. We investigated the filtering of a colloidal suspension by a thin film of functionalized macromolecules in a microchannel using the technique of Small-angle X-ray scattering (SAXS). SAXS is a nonintrusive measurement technique that enables in situ investigations of the interaction between the functionalized macromolecules and the flowing nanoparticles on the nanoscale. We present our findings on the filtered nanoparticles by the thin film of macromolecules and give an outlook on how to optimize the filtering ability of the thin film based on the in situ SAXS measurements. \\[0pt] [1] Eijkel, \textit{et al.} Micro. Nano. 1, 249 (2005). [2] Schooch, \textit{et al.} Rev. mod. Phy., 80, 840 (2008). [3] Chen \textit{et al., }Small 7, 1061 (2011). [Preview Abstract] |
Sunday, November 18, 2012 8:39AM - 8:52AM |
A30.00004: Carbon Nanotube Micro-Needles for Rapid Transdermal Drug Delivery Bradley Lyon, Adrianus Indrat Aria, Amir Gat, Julia Cosse, Lauren Montemayor, Masoud Beizaie, Morteza Gharib By catalyst patterning, bundles of vertically-aligned carbon nanotubes (CNT) can be assembled to create 2D arrays of hollow micro-needles with feature size as small as a few microns. For transdermal drug delivery, the most challenging mechanical requirement is to make the CNT micro-needle small enough so that delivery is painless yet large enough so that the micro-needle can achieve skin penetration. By taking advantage of capillary action and the nanoporosity of CNT bundles, we can wick high strength polymer into the inter-spacing between nanotubes to augment the stiffness of our micro-needles. For low viscous polymers, the large ratio between the micron sized center hole of the micro-needle and the nanopores of the surrounding CNT allow us to wick polymer through the nanotubes while maintaining an open central hole for drug transport. For a transdermal patch prototype with a delivery area less than 1cm x 1cm square, we can fabricate 50 CNT micro-needles that produces a total flow rate up to 100 uL/s with actuation pressure provided by a mere finger tap. From in vitro experiments, we will demonstrate that CNT micro-needles provide a much faster convective delivery of drugs than conventional topical diffusion based patches. [Preview Abstract] |
Sunday, November 18, 2012 8:52AM - 9:05AM |
A30.00005: Brownian Diffusion of Nanoparticles in Confined Geometries Shahram Pouya, Manoochehr Koochesfahani The transport and motion of nanoparticles is an important aspect of designing micro and nano fluidic devices for biological and chemical analysis. We present preliminary measurements of hydrodynamics of nanoparticles in micro- and nano-confined geometries. Brownian fluctuation of nanoparticles is investigated by imaging the motion of single nanoparticles inside nano/micro gaps at different confinement ratios. The results are presented for the case of zero shear rate, where only pure diffusive motion of nanoparticles within the gap is considered. Results are compared with previous measurements using a different approach and models of this process. [Preview Abstract] |
Sunday, November 18, 2012 9:05AM - 9:18AM |
A30.00006: How surface functional groups influence fracturation in nanofluids droplets dry-outs David Brutin, Florian Carle We report an experimental investigation of the drying of a deposited droplets of nanofluids with different surface functional groups. For identical nano-particles diameter, material and concentration, identical drying conditions, the substrate and the functional groups at the nano- particles surface are changed. Both flow motion, adhesion, gelation and fracturation occur during the evaporation of this complex matter leading to different final typical patterns. The differences in between the patterns are explained based on the surface chemical potential. Crack shapes and wavelengths are globally proportional to the electrical charges carried at the nano- particles surface which is a new parameter to implement in existing predicting models. Presently only the colloid concentration and softness and the deposit thickness are used (Allain and Limat, 1995). C. Allain and L. Limat, Regular Patterns of Cracks Formed by Directional Drying of a Colloidal Suspension, Phys. Rev. Lett., 74, 2981-2984 (1995). [Preview Abstract] |
Sunday, November 18, 2012 9:18AM - 9:31AM |
A30.00007: Electrodeless electro-hydrodynamic printing of nano-suspensions for personalized medicines Ezinwa Elele, Yueyang Shen, Rajyalakshmi Boppana, Afolawemi Afolabi, Ecevit A. Bilgili, Boris Khusid Drop-on-demand (DOD) dosing is a promising strategy for manufacturing of personalized medicines. However, current DOD methods developed for chemically and thermally stable, low-viscosity inks are of limited use for pharmaceuticals due to fundamentally different functional requirements. To overcome their deficiency, we developed an electro-hydrodynamic (EHD) DOD method (Appl Phys Lett 97, 233501, 2010) that operates on fluids of up to 30 Pas over a wide range of droplet sizes, does not require direct contact of a fluid with electrodes and provides a precise control over the droplet volume. As most drugs are poorly water soluble, the use of nanoparticles dispersed in water is a promising method for enhancing the drug dissolution rate and bioavailability. The work demonstrates the EHD DOD ability to print aqueous suspensions of drug nanoparticles on highly-porous polymer films. We present a scaling analysis that captures the essential physics of drop evolution. These results show that EHD DOD offers a powerful tool for the evolving field of pharmaceutical technologies for tailoring medicines to individual patient's needs by printing a vast array of predefined amounts of therapeutics arranged in a specific pattern on a porous film. [Preview Abstract] |
Sunday, November 18, 2012 9:31AM - 9:44AM |
A30.00008: Experimental Nanofluidics in an individual Nanotube Alessandro Siria, Philippe Poncharal, Anne Laure Biance, Remy Fulcrand, Stephen Purcell, Lyderic Bocquet Building new devices that benefit from the strange transport behavior of fluids at nanoscales is an open and worthy challenge that may lead to new scientific and technological paradigms. [1-3] We present here a new class of nanofluidic device, made of individual Boron-Nitride (BN) nanotube inserted in a pierced membrane and connecting two macroscopic reservoirs. We explore fluidic transport inside a single BN nanotube under electric fields, pressure drops, chemical gradients, and combinations of these. We show that in this transmembrane geometry, the pressure-driven streaming current is voltage gated, with an apparent electro-osmotic zeta potential raising up to one volt. Further, we measured the current induced by ion concentration gradients and show its dependency on the surface charge.\\[4pt] [1] L. Bocquet, E. Charlaix, Chem. Soc. Rev., 39, 1073 (2010).\newline [2] M. Majumder et al., Nature 2005, 438, 44.\newline [3] J.K. Holt et al. Science 2006, 312, 1034. [Preview Abstract] |
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