Browsing by Author "Kanik, M."

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Open Access
Arrays of indefinitely long uniform nanowires and nanotubes
(Nature Publishing Group, 2011) Yaman, M.; Khudiyev, T.; Ozgur E.; Kanik, M.; Aktas, O.; Ozgur, E. O.; Deniz, H.; Korkut, E.; Bayındır, Mehmet
Nanowires are arguably the most studied nanomaterial model to make functional devices and arrays. Although there is remarkable maturity in the chemical synthesis of complex nanowire structures, their integration and interfacing to macro systems with high yields and repeatability still require elaborate aligning, positioning and interfacing and post-synthesis techniques. Top-down fabrication methods for nanowire production, such as lithography and electrospinning, have not enjoyed comparable growth. Here we report a new thermal size-reduction process to produce well-ordered, globally oriented, indefinitely long nanowire and nanotube arrays with different materials. The new technique involves iterative co-drawing of hermetically sealed multimaterials in compatible polymer matrices similar to fibre drawing. Globally oriented, endlessly parallel, axially and radially uniform semiconducting and piezoelectric nanowire and nanotube arrays hundreds of metres long, with nanowire diameters less than 15ĝ€‰nm, are obtained. The resulting nanostructures are sealed inside a flexible substrate, facilitating the handling of and electrical contacting to the nanowires. Inexpensive, high-throughput, multimaterial nanowire arrays pave the way for applications including nanowire-based large-area flexible sensor platforms, phase-changememory, nanostructure-enhanced photovoltaics, semiconductor nanophotonics, dielectric metamaterials,linear and nonlinear photonics and nanowire-enabled high-performance composites. © 2011 Macmillan Publishers Limited. All rights reserved.
Open Access
Bio-inspired hierarchically structured polymer fibers for anisotropic non-wetting surfaces
(Royal Society of Chemistry, 2017) Yunusa, M.; Ozturk, F. E.; Yildirim, A.; Tuvshindorj, U.; Kanik, M.; Bayındır, Mehmet
We demonstrate a rice leaf-like hierarchically textured polymer fiber array for anisotropic non-wetting surfaces. To provide superhydrophobicity in addition to the anisotropic behavior, fiber surfaces are spray coated with organically modified silica nanoparticles. The resulting micro/nano hierarchically structured fiber surfaces demonstrate anisotropic non-wetting properties. We designed various fiber architectures for droplet transportation, mixing, and guiding exploiting the scalability of the fiber texture during thermal drawing; optional nanoparticle surface modification; and inherent flexibility of the fibers.
Open Access
Continuous triboelectric power harvesting and biochemical sensing inside poly(vinylidene fluoride) hollow fibers using microfluidic droplet generation
(Wiley-Blackwell, 2016-11) Kanik, M.; Marcali, M.; Yunusa, M.; Elbuken, C.; Bayındır, Mehmet
Triboelectric power harvesting and biochemical sensing inside poly(vinylidene fluoride) hollow fibers. Fiber‐based microfluidic energy harvesting system, which is also utilized as self‐powered chemical and biosensor. In vitro device concept demonstrating that triboelectric effect can be used for cell detection.
Open Access
High selectivity boolean olfaction using hollow-core wavelength-scalable Bragg fibers
(American Chemical Society, 2012) Yaman, M.; Yildirim, A.; Kanik, M.; Cinkara, T. C.; Bayındır, Mehmet
A new odorant detection scheme, based on infrared absorption of volatile organics inside an optofluidic channel array, is discussed in terms of its selectivity. The sensor unit of the array is a hollow core Bragg fiber that selectively (spectrally) guides an incident continuum radiation. The presence of infrared absorbing molecules in the channel results in the quenching of the otherwise transmitted signal. Each fiber unit in the array is designed and fabricated so that it is sensitive to specific chemical bonds and the bond environment, but at the same time, each fiber is also broadly sensitive to a large number of chemicals due to their infrared absorbance spectra. The cumulative array response data, using an appropriate threshold, enable selective binary sampling of the infrared fingerprint of hundreds of molecules. The selectivity of the system is quantitatively investigated with computer simulations and found to be exponentially increasing with the number of fibers in the array. Relatively simple data analysis using binary logic combined with the high selectivity of the novel scheme paves the way for ubiquitous application of electronic noses in toxic gas detection, food quality control, environmental monitoring, and breath analysis for disease diagnostics. © 2011 American Chemical Society.
Open Access
Macroscopic assembly of indefinitely long and parallel nanowires into large area photodetection circuitry
(American Chemical Society, 2012) Ozgur E.; Aktas, O.; Kanik, M.; Yaman, M.; Bayındır, Mehmet
Integration of nanowires into functional devices with high yields and good reliability turned out to be a lot more challenging and proved to be a critical issue obstructing the wide application of nanowire-based devices and exploitation of their technical promises. Here we demonstrate a relatively easy macrofabrication of a nanowire-based imaging circuitry using a recently developed nanofabrication technique. Extremely long and polymer encapsulated semiconducting nanowire arrays, mass-produced using the iterative thermal drawing, facilitate the integration process; we manually aligned the fibers containing selenium nanowires over a lithographically defined circuitry. Controlled etching of the encapsulating polymer revealed a monolayer of nanowires aligned over an area of 1 cm 2 containing a 10 × 10 pixel array. Each light-sensitive pixel is formed by the contacting hundreds of parallel photoconductive nanowires between two electrodes. Using the pixel array, alphabetic characters were identified by the circuitry to demonstrate its imaging capacity. This new approach makes it possible to devise extremely large nanowire devices on planar, flexible, or curved substrates with diverse functionalities such as thermal sensors, phase change memory, and artificial skin. © 2012 American Chemical Society.
Open Access
A motion-and sound-activated, 3D-printed chalcogenide-based triboelectric nanogenerator
(Wiley-VCH Verlag, 2015) Kanik, M.; Say, M. G.; Daglar, B.; Yavuz, A. F.; Dolas, M. H.; El-Ashry, M. M.; Bayındır, Mehmet
A multilayered triboelectric nanogenerator (MULTENG) that can be actuated by acoustic waves, vibration of a moving car, and tapping motion is built using a 3D-printing technique. The MULTENG can generate an open-circuit voltage of up to 396 V and a short-circuit current of up to 1.62 mA, and can power 38 LEDs. The layers of the triboelectric generator are made of polyetherimide nanopillars and chalcogenide core-shell nanofibers.
Open Access
A new route for fabricating on-chip chalcogenide microcavity resonator arrays
(Wiley-VCH Verlag, 2014-07) Aktas, O.; Ozgur E.; Tobail, O.; Kanik, M.; Huseyinoglu, E.; Bayındır, Mehmet
High-yield production and on-chip integration of high-Q chalcogenide microresonators with various sizes and geometrical shapes (spherical, spheroidal, and ellipsoidal) and with sub-nanometer surface roughness is achieved. The high-throughput and low-cost production of chalcogenide spherical microresonators works via inducing a Plateau-Rayleigh instability within a multimaterial fiber in extended lengths. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Open Access
Photonic bandgap narrowing in conical hollow core Bragg fibers
(AIP Publishing, 2014) Ozturk, F. E.; Yildirim, A.; Kanik, M.; Bayındır, Mehmet
We report the photonic bandgap engineering of Bragg fibers by controlling the thickness profile of the fiber during the thermal drawing. Conical hollow core Bragg fibers were produced by thermal drawing under a rapidly alternating load, which was applied by introducing steep changes to the fiber drawing speed. In conventional cylindrical Bragg fibers, light is guided by omnidirectional reflections from interior dielectric mirrors with a single quarter wave stack period. In conical fibers, the diameter reduction introduced a gradient of the quarter wave stack period along the length of the fiber. Therefore, the light guided within the fiber encountered slightly smaller dielectric layer thicknesses at each reflection, resulting in a progressive blueshift of the reflectance spectrum. As the reflectance spectrum shifts, longer wavelengths of the initial bandgap cease to be omnidirectionally reflected and exit through the cladding, which narrows the photonic bandgap. A narrow transmission bandwidth is particularly desirable in hollow waveguide mid-infrared sensing schemes, where broadband light is coupled to the fiber and the analyte vapor is introduced into the hollow core to measure infrared absorption. We carried out sensing simulations using the absorption spectrum of isopropyl alcohol vapor to demonstrate the importance of narrow bandgap fibers in chemical sensing applications.
Open Access
Spontaneous high piezoelectricity in poly ( vinylidene fluoride ) nanoribbons produced by iterative thermal size reduction technique
(American Chemical Society, 2014-08-18) Kanik, M.; Aktas, O.; Sen, H. S.; Durgun, Engin; Bayındır, Mehmet
We produced kilometer-long, endlessly parallel, spontaneously piezoelectric and thermally stable poly(vinylidene fluoride) (PVDF) micro- and nanoribbons using iterative size reduction technique based on thermal fiber drawing. Because of high stress and temperature used in thermal drawing process, we obtained spontaneously polar gamma phase PVDF micro- and nanoribbons without electrical poling process. On the basis of X-ray diffraction (XRD) analysis, we observed that PVDF micro- and nanoribbons are thermally stable and conserve the polar gamma phase even after being exposed to heat treatment above the melting point of PVDF. Phase transition mechanism is investigated and explained using ab initio calculations. We measured an average effective piezoelectric constant as -58.5 pm/V from a single PVDF nanoribbon using a piezo evaluation system along with an atomic force microscope. PVDF nanoribbons are promising structures for constructing devices such as highly efficient energy generators, large area pressure sensors, artificial muscle and skin, due to the unique geometry and extended lengths, high polar phase content, high thermal stability and high piezoelectric coefficient. We demonstrated two proof of principle devices for energy harvesting and sensing applications with a 60 V open circuit peak voltage and 10 mu A peak short-circuit current output.
Open Access
Surface textured polymer fibers for microfluidics
(WILEY-VCH Verlag GmbH & Co. KGaA, 2014) Yildirim, A.; Yunusa, M.; Ozturk, F. E.; Kanik, M.; Bayındır, Mehmet
This article introduces surface textured polymer fibers as a new platform for the fabrication of affordable microfluidic devices. Fibers are produced tens of meters-long at a time and comprise 20 continuous and ordered channels (equilateral triangle grooves with side lengths as small as 30 micrometers) on their surfaces. Extreme anisotropic spreading behavior due to capillary action along the grooves of fibers is observed after surface modification with polydopamine (PDA). These flexible fibers can be fixed on any surface - independent of its material and shape - to form three-dimensional arrays, which spontaneously spread liquid on predefined paths without the need for external pumps or actuators. Surface textured fibers offer high-throughput fabrication of complex open microfluidic channel geometries, which is challenging to achieve using current photolithography-based techniques. Several microfluidic systems are designed and prepared on either planar or 3D surfaces to demonstrate outstanding capability of the fiber arrays in control of fluid flow in both vertical and lateral directions. Surface textured fibers are well suited to the fabrication of flexible, robust, lightweight, and affordable microfluidic devices, which expand the role of microfluidics in a scope of fields including drug discovery, medical diagnostics, and monitoring food and water quality.