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Yang Yang, Yong Gang Li, Michael P Short, Chung-Soo Kim, Karl K Berggren, Ju Li
Full three dimensional (3D) simulations of ion implantation are necessary in a wide range of nanoscience and nanotechnology applications to capture the increasing effect of ion leakage out of surfaces. Using a recently developed 3D Monte Carlo simulation code IM3D, we first quantify the relative error of the 1D approach in three applications of nano-scale ion implantation: (1) nano-beam for nitrogen-vacancy (NV) center creation, (2) implantation of nanowires to fabricate p-n junctions, and (3) irradiation of nano-pillars for small-scale mechanical testing of irradiated materials...
January 11, 2018: Nanoscale
Peng Huang, Qian Yu
"Smaller is stronger" has been commonly observed in cubic structured and hexagonal close-packed (HCP) structured materials. Dislocation starvation phenomenon is highly responsible for the increase of strength at smaller scale in cubic materials. However, by using quantitative in situ transmission electron microscope (TEM) nano-mechanical testing on cylindrical titanium nano-pillars with diameters of ~150 nm but varied orientations and three dimensional dislocation tomography, we found that dislocation nucleation and multiplication dominate the plastic deformation of the nano-pillars with no sign of dislocation starvation, resulting in much better ability of dislocation storage and plastic stability of HCP structured materials at extremely small scale...
November 21, 2017: Scientific Reports
Sayed Ali Akbar Razavi, Mohammad Yaser Masoomi, Ali Morsali
A pillared MOF, [Zn(OBA)(H2DPT)0.5].DMF (TMU-34), based on dihydro tetrazine functionalized pillar spacer (H2DPT=3,6-di(pyridin-4-yl)-1,4-dihydro-1,2,4,5-tetrazine) and V-shape dicarboxylate linker (H2OBA=4,4'-oxybis(benzoic acid)) was synthesized by reflux and ultrasonic methods. The effects of sonication time, initial concentration of reagents and sonication power on size and morphology have been optimized. This MOF has been characterized by scanning electron microscopy, FT-IR spectra, X-ray powder diffraction and N2 adsorption at 77K...
March 2018: Ultrasonics Sonochemistry
Qun Wang, Menghao Wang, Xiong Lu, Kefeng Wang, Liming Fang, Fuzeng Ren, Guoming Lu
Hydroxyapatite (HA) is the principal inorganic component of bones and teeth and has been widely used as a bone repair material because of its good biocompatibility and bioactivity. Understanding the interactions between proteins and HA is crucial for designing biomaterials for bone regeneration. In this study, we evaluated the effects of atomic-level nano-structured HA (110) surfaces on the adsorption of bone morphogenetic protein-7 (BMP-7) and its derived peptide (KQLNALSVLYFDD) using molecular dynamics and density functional theory methods...
November 9, 2017: Scientific Reports
Shasha Qiao, Shen Li, Qunyang Li, Bo Li, Kesong Liu, Xi-Qiao Feng
Liquid transport is a fundamental process relevant to a wide range of applications, e.g. heat transfer, anti-icing, self-cleaning, drag reduction, and microfluidic systems. For these applications, a deeper understanding of the sliding behavior of water droplets on solid surfaces is of particular importance. In this study, the frictional behavior of water droplets sliding on superhydrophobic surfaces decorated with micro-pillar arrays was studied using a nano-tribometer. Our experiments show that surfaces with a higher solid area fraction generally exhibited larger friction, although friction might drop when the solid area fraction was close to unity...
November 2, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Guillaume Raffy, Robin Bofinger, Arnaud Tron, André Del Guerzo, Nathan D McClenaghan, Jean-Marc Vincent
An innovative photopatterning process is described that allows, in a single laser-promoted operation, the covalent attachment of a molecule on a surface (2D patterning - xy dimensions) and its photopolymerization to grow micro-/nanostructures with spatial control in a third z-dimension. The surface patterning process, based on nitrene reactivity, was harnessed using the highly fluorescent azide-substituted boron difluoride dipyrromethene (BODIPY) 1 that was prepared in a single synthetic step from the parent pentafluorophenyl BODIPY on reacting with NaN3...
November 9, 2017: Nanoscale
Loïc Berthod, Olga Shavdina, Isabelle Verrier, Thomas Kämpfe, Olivier Dellea, Francis Vocanson, Maxime Bichotte, Damien Jamon, Yves Jourlin
This paper presents substantial improvements of the colloidal photolithography technique (also called microsphere lithography) with the goal of better controlling the geometry of the fabricated nano-scale structures-in this case, hexagonally arranged nanopillars-printed in a layer of directly photopatternable sol-gel TiO₂. Firstly, to increase the achievable structure height the photosensitive layer underneath the microspheres is deposited on a reflective layer instead of the usual transparent substrate. Secondly, an increased width of the pillars is achieved by tilting the incident wave and using multiple exposures or substrate rotation, additionally allowing to better control the shape of the pillar's cross section...
October 12, 2017: Nanomaterials
Shan Gao, Quanwen Liao, Wei Liu, Zhichun Liu
Recently, numerous studies focused on the wetting process of droplets on various surfaces at a microscale level. However, there are a limited number of studies about the mechanism of condensation on patterned surfaces. The present study performed the dynamic wetting behavior of water droplets and condensation process of water molecules on substrates with different pillar structure parameters, through molecular dynamic simulation. The dynamic wetting results indicated that droplets exhibit Cassie state, PW state, and Wenzel state successively on textured surfaces with decreasing solid fraction...
October 18, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Jon Ashley, Kaiyu Wu, Mikkel Fougt Hansen, Michael Stenbæk Schmidt, Anja Boisen, Yi Sun
There is an increasing demand for rapid, sensitive, and low cost analytical methods to routinely screen antibiotic residues in food products. Conventional detection of antibiotics involves sample preparation by liquid-liquid or solid-phase extraction, followed by analysis using liquid chromatography-mass spectrometry (LC-MS), capillary electrophoresis (CE), or gas chromatography (GC). The process is labor-intensive, time-consuming, and expensive. In this study, we developed a new analytical method that combines magnetic molecularly imprinted polymer (MMIP)-based sample preparation with surface-enhanced Raman spectroscopy (SERS)-based detection for quantitative analysis of cloxacillin in pig serum...
November 7, 2017: Analytical Chemistry
Kiyoshi Minoura, Miho Yamada, Takashi Mizoguchi, Toshihiro Kaneko, Kyoko Nishiyama, Mari Ozminskyj, Tetsuo Koshizuka, Ikuo Wada, Tatsuo Suzutani
The antibacterial effect of a nanostructured film, known as "moth-eye film," was investigated. The moth-eye film has artificially formed nano-pillars, consisting of hydrophilic resin with urethane acrylate and polyethylene glycol (PEG) derivatives, all over its surface that replicates a moth's eye. Experiments were performed to compare the moth-eye film with a flat-surfaced film produced from the same materials. The JIS Z2801 film-covering method revealed that the two films produced a decrease in Staphylococcus aureus and Esherichia coli titers of over 5 and 3 logs, respectively...
2017: PloS One
Dimitri Khaghani, Mathieu Lobet, Björn Borm, Loïc Burr, Felix Gärtner, Laurent Gremillet, Liana Movsesyan, Olga Rosmej, Maria Eugenia Toimil-Molares, Florian Wagner, Paul Neumayer
The interaction of micro- and nano-structured target surfaces with high-power laser pulses is being widely investigated for its unprecedented absorption efficiency. We have developed vertically aligned metallic micro-pillar arrays for laser-driven proton acceleration experiments. We demonstrate that such targets help strengthen interaction mechanisms when irradiated with high-energy-class laser pulses of intensities ~10(17-18) W/cm(2). In comparison with standard planar targets, we witness strongly enhanced hot-electron production and proton acceleration both in terms of maximum energies and particle numbers...
September 12, 2017: Scientific Reports
Nina Buch-Månson, Arnaud Spangenberg, Laura Piedad Chia Gomez, Jean-Pierre Malval, Olivier Soppera, Karen L Martinez
Mammalian cells have been widely shown to respond to nano- and microtopography that mimics the extracellular matrix. Synthetic nano- and micron-sized structures are therefore of great interest in the field of tissue engineering, where polymers are particularly attractive due to excellent biocompatibility and versatile fabrication methods. Ordered arrays of polymeric pillars provide a controlled topographical environment to study and manipulate cells, but processing methods are typically either optimized for the nano- or microscale...
August 23, 2017: Scientific Reports
Jaeho Choi, Wonhee Jo, Seung Yeol Lee, Yeon Sik Jung, Shin-Hyun Kim, Hee-Tak Kim
Springtails, insects which breathe through their skins, possess mushroom-shaped nanostructures. As doubly re-entrant geometry in the mushroom head enhances the resistance against liquid invasion, the springtails have robust, liquid-free omniphobic skins. Although omniphobic surfaces are promising for various applications, it remains an important challenge to mimic the structural feature of springtails. This paper presents a pragmatic method to create doubly re-entrant nanostructures and robust superomniphobic surfaces by exploiting localized photofluidization of azopolymers...
August 22, 2017: ACS Nano
Yuan Yuan, Yugen Zhang
Cicada wing surfaces are covered with dense patterns of nano-pillar structure that prevent bacterial growth by rupturing adhered microbial cells. To mimic the natural nano-pillar structure, we developed a general and simple method to grow metal organic framework (MOF) nano-dagger arrays on a wide range of surfaces. These nano-daggers possess high bactericidal activity, with log reduction >7 for Escherichia coli and Staphylococcus aureus. It was hypothesized that the positively-charged ZIF-L nano-dagger surfaces enhance bacterial cell adhesion, facilitating selective and efficient bacteria killing by the rigid and sharp nano-dagger tips...
October 2017: Nanomedicine: Nanotechnology, Biology, and Medicine
Eddy M Domingues, Sankara Arunachalam, Himanshu Mishra
Omniphobic surfaces, that is, which repel all known liquids, have proven of value in applications ranging from membrane distillation to underwater drag reduction. A limitation of currently employed omniphobic surfaces is that they rely on perfluorinated coatings, increasing cost and environmental impact and preventing applications in harsh environments. Thus, there is a keen interest in rendering conventional materials, such as plastics, omniphobic by micro/nanotexturing rather than via chemical makeup, with notable success having been achieved for silica surfaces with doubly reentrant micropillars...
June 19, 2017: ACS Applied Materials & Interfaces
David Eisenhauer, Grit Köppel, Klaus Jäger, Duote Chen, Oleksandra Shargaieva, Paul Sonntag, Daniel Amkreutz, Bernd Rech, Christiane Becker
Recently, liquid phase crystallization of thin silicon films has emerged as a candidate for thin-film photovoltaics. On 10 μm thin absorbers, wafer-equivalent morphologies and open-circuit voltages were reached, leading to 13.2% record efficiency. However, short-circuit current densities are still limited, mainly due to optical losses at the glass-silicon interface. While nano-structures at this interface have been shown to efficiently reduce reflection, up to now these textures caused a deterioration of electronic silicon material quality...
June 1, 2017: Scientific Reports
Rachel B Strickhouser, Nahla A Hatab, Nickolay V Lavrik, Michael J Sepaniak
A fundamental problem with efficiency in capillary action driven planar chromatography results from diminishing flow rates as development proceeds, giving rise to molecular diffusion related band dispersion for most sample types. Overpressure and electrokinetic means to speed flow have been used successfully in TLC. We explore the use of centrifugal force (CF) to drive flow for reduced-dimension planar platforms (ultra-TLC, low μm features, and nano-TLC, nanoscale features). The silicon wafer platforms have two forms of continuous 2-D arrays created by either photolithography or metal dewetting followed by deep reactive ion etching and coated with porous SiO2 ...
May 15, 2017: Electrophoresis
J J Bailey, T M M Heenan, D P Finegan, X Lu, S R Daemi, F Iacoviello, N R Backeberg, O O Taiwo, D J L Brett, A Atkinson, P R Shearing
A robust and versatile sample preparation technique for the fabrication of cylindrical pillars for imaging by X-ray nano-computed tomography (nano-CT) is presented. The procedure employs simple, cost-effective laser micro-machining coupled with focused-ion beam (FIB) milling, when required, to yield mechanically robust samples at the micrometre length-scale to match the field-of-view (FOV) for nano-CT imaging. A variety of energy and geological materials are exhibited as case studies, demonstrating the procedure can be applied to a variety of materials to provide geometrically optimised samples whose size and shape are tailored to the attenuation coefficients of the constituent phases...
September 2017: Journal of Microscopy
Sayed Ali Akbar Razavi, Mohammad Yaser Masoomi, Ali Morsali
TMU-34(-2H), [Zn(OBA)(DPT)0.5].DMF, has been sonochemically synthesized by applying H2OBA, (4,4'-oxybis(benzoic acid)), as the dicarboxylate linker, and DPT, (3,6-di(pyridin-4-yl)-1,2,4,5-tetrazine), as pillar spacer. Sonication time, concentration of initial reagents, sonication power and molar ratio of pyridine as modulator has been optimized to synthesize nano powder of TMU-34(-2H) including uniform plate morphology. Nano TMU-34(-2H), can detect phenylhydrazine (PH) by color changing from pink to deep purple...
July 2017: Ultrasonics Sonochemistry
Yuhang Jiang, Jinhai Mao, Junxi Duan, Xinyuan Lai, Kenji Watanabe, Takashi Taniguchi, Eva Y Andrei
Graphene's remarkable properties are inherent to its two-dimensional honeycomb lattice structure. Its low dimensionality, which makes it possible to rearrange the atoms by applying an external force, offers the intriguing prospect of mechanically controlling the electronic properties. In the presence of strain, graphene develops a pseudomagnetic field (PMF) that reconstructs the band structure into pseudo Landau levels (PLLs). However, a feasible route to realizing, characterizing and controlling PMFs is still lacking...
April 24, 2017: Nano Letters
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