bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tailor-Made Nanostructured Ion Selective MCM-48 Membranes
Authors: Chowdhury Sankhanilay Roy , Schmuhl Riaan , Keizer Klaas , Berg Albert van den , ten Elshof Johan E. , Blank Dave H.A. 
Published: June 2019

AbstractMesoporous templated MCM-48 silica was prepared using a C16 surfactant as template. The MCM-48 powders and thin films were characterized by different techniques. Two types of porous supports were used, namely macroporous á-alumina and silicon microsieves. The supported MCM-48 layers were applied as liquid permeable membranes in pressure-driven nanofiltration and electric field-mediated ion transport experiments.
Hierarchically Structured Silica Monoliths
Authors: Hüsing Nicola , Raab Christina , Torma Viktoria 
Published: June 2019

AbstractLarge monoliths with periodic mesopores in a macroporous web-like network structure are prepared using a diol-modified silane as silica precursor and lyotropic liquid crystalline phases of surfactants in water as structure-directing agents. The surfactant concentration is varied from 5 to 40wt%. Highly porous materials are synthesized applying two different drying procedures: supercritical drying with CO2 or ethanol, in addition to ambient pressure drying including surfactant expulsion via silanisation treatments with trimethylchlorosilane or hexamethyl disilazane. The monolithic materials show a very unique macro- and mesostructure which is characterized by N2-sorption measurements, small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM) and scanning electron microscopy (SEM).
Self-assembly PbSe Nanoparticles into Nanorings
Authors: Zhou Weilie L. , He Jibao , Fang Jiye , Huynh Tuyet-Anh , Kennedy Trevor J. , Stokes Kevin L. , O'Connor Charles J. 
Published: June 2019

AbstractIn this presentation, we report the self-assembly of monolayer and multilayer nanorings of PbSe nanoparticles. PbSe nanoparticles were synthesized by using a high temperature precipitation method. The nanoparticles are about 5 nm and appeared as truncated octahedral enclosed by the {100} and {111} crystal facets of fcc structure. The large area monodisperse self-assembly nanoarrays were obtained by dropping the high concentration solution of PbSe nanoparticles on the carbon grid. The nanoparticles are hexagonal close packed and oriented randomly in the nanoarrays. By diluting the solution for large area self-assembly, self-assembly of monolayer and multilayer nanorings can be achieved. The nanoring formation is determined by hydrodynamics, surface effects, and interaction between the nanoparticles and carbon grid.
Palladium Nanowire Thin Films via Template Growth
Authors: Wang Donghai , Johnson David T. , McCaughey Byron F. , Hampsey J. Eric , He Jibao , Lu Yunfeng 
Published: June 2019

AbstractPalladium nanowires have been electrodeposited into mesoporous silica thin film templates. Palladium continually grows and fills silica mesopores starting from a bottom conductive substrate, providing a ready and efficient route to fabricate a macroscopic palladium nanowire thin films for potentially use in fuel cells, electrodes, sensors, and other applications. X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicate it is possible to create different nanowire morphology such as bundles and swirling mesostructure based on the template pore structure.
Stable Nanocapsules Formed from Headgroup Polymerization of Natural Phospholipids
Authors: Lawson Glenn E. , Singh Alok 
Published: June 2019

AbstractFormation of lipid based hollow, spherical nanocapsules is reported. N-acylphosphotidylethanolamine (egg) derivatives equipped with divinylbenzoyl functionality in their headgroup region were synthesized to explore their polymerization behavior in vesicles. Polymerizable phospholipids alone produced vesicles as an aqueous dispersion and produced stable nanocapsules upon polymerization at room temperature. These structures survived a redispersed cycle following lyophilization and maintained their structural integrity in non-aqueous solvent.
Interface-dependence of Nucleation and Self-Assembly of Ultrathin Iron Oxide Films
Authors: Ketteler Guido , Ranke Wolfgang 
Published: June 2019

AbstractThe interface-dependence of heteroepitaxial growth of iron oxide films is investigated by scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED). We show that the different chemical affinity to the metal substrate (Ru vs. Pt) and the step density (basal vs. vicinal Pt) significantly influence nucleation, heteroepitaxial crystal growth, and adhesion. Repeated Fe deposition-oxidation cycles lead to a Stranski-Krastanov growth mode on all substrates. On Ru(0001), metastable FeO(111) layers with strongly expanded lattice constants with a thickness up to 4 monolayers (ML) can be obtained by one-minute oxidation of the corresponding amount of Fe. Homogeneous nucleation of self-assembled, periodic Fe304(111) nanodomains embedded in an ultrathin FeO(111) film occurs on Ru(0001) in ∼4 ML thick FeO(111) films. Nucleation of Fe304(111) islands below 4 ML on Ru(0001) occurs preferentially at substrate step edges while on Pt(111), no influence of surface defects was observed. On a vicinal Pt substrate, the terrace width and step height triplicates under influence of the wetting FeO(111) film. Differences in the growth behavior are discussed in terms of the involved surface and interface free energies.
Substrate Dependent Bonding of Chemisorbed 1,1'-Biphenyl-4,4'-Dimethanethiol
Authors: Caruso A.N. , Rajesekaran R. , Redepenning J. , Losovyj Ya.B. , Dowben P. A. 
Published: June 2019

AbstractWe compare the adsorption of 1,1'-biphenyl-4,4'-dimethanethiol (BPDMT) on gold and cobalt surfaces. The molecular orbitals, identified from combined photoemission and inverse photoemission studies, exhibit shifts in binding energies with different deposition methods and substrates. These shifts indicate that this potential molecular dielectric exhibits stronger bonding to cobalt surfaces than gold surfaces.
Self-Assembled Organic-Inorganic Silica Hybrids From Polyviologens
Authors: Gray Graham M. , Hay John N. 
Published: June 2019

AbstractPolyviologens (bipyridinium polymers) are effective catalysts for the polymerisation of silicic acid at room temperature and neutral pH. Variations in the alkylene spacer length and the associated counter ion appear to have little, if any, effect upon the rate of polymerisation as measured by the colorimetric molybdosilicate method. The resultant hybrid materials are amorphous aggregates of roughly spherical particles typically less than 0.1μm in diameter.
Towards Monodomains of Self-Organized Comb-Shaped Polymeric Supramolecules
Authors: Ikkala Olli , Brinke Gerrit ten 
Published: June 2019

AbstractWe have previously shown that hierarchical self-organization is achieved upon physically bonding amphiphilic molecules to diblock copolymers. Here we discuss the effect of imposed shear flow to achieve overall alignment of the locally self-organized structures. We will first present shear aligned polystyrene-block-poly(4-vinyl pyridine) diblock copolymers (PS-b-P4VP), where pentadecyl phenol (PDP) has been hydrogen bonded to the pyridines. Depending on the selected molecular weights, eg. hexagonal arrangement of PS cylinders in the lamellar matrix of P4VP(PDP) can be obtained with high overall order of both structures. This is a template to obtain discrete PS nanorods, which have P4VP corona once the PDP molecules have been cleaved off by a solvent treatment. Selecting a relatively high molecular weight PS block and a short P4VP block leads to mesoporous materials with emptied cylinders with P4VP brushes at the walls. The glassy state of the PS matrix prevents the pores from collapsing. The pyridine groups of PS-b-P4VP can be protonated using eg. toluene sulphonic acid and the resulting polymeric salt has been complexed using PDP. The weight fractions have been selected so that the polyelectrolyte/amphiphile complex self-organizes into cylindrical domains with hexagonal packing. Shear alignment leads to high overall order. SAXS in combination with structural models suggests that within the cylinders there are parallel self-organized layers. The conductivity is anisotropic. We will also discuss dielectric reflectors based on self-organized block polyelectrolytes consisting PS-b-P4VP where DBSA has been complexed to P4VP. In this case, plasticization due to the oligomeric side chains promotes a facile structure formation at long periodicities in comparison to concepts based on eg. blends of high molecular weight polymers and block copolymers. Finally, plasticized comb-shaped supramolecules based on rigid conjugated poly(p-pyridine) are discussed. Even gentle shearing leads to highly aligned lamellar structures, which show efficient polarized photoluminescence.
The Preparation of Large Scale Monolayers of Gold Nanoparticles on Modified Silicon Substrates using a Controlled Pulling Method
Authors: Tilley Richard , Saito Satoshi , Mastui Isao 
Published: June 2019

AbstractThe preparation of large scale monolayers of dodecanethiol coated nanoparticles on modified silicon substrates for use in storage media is reported. The formation of nanoparticle monolayers was accomplished by vertically pulling various modified silicon substrates at controlled speeds from nanoparticle solutions. The silicon substrates investigated had silanol and hydrogen terminated surfaces, surfaces chemically modified by (CH3) 3SiNHSi(CH3) 3 and (CH3O) 3Si(CH2)2(CF2) 7CF3 and a silicon substrate coated with amorphous carbon. All of these substrates have different surface polarities and a wide variation in monolayer coverage was obtained. The effect of the substrate pulling speed and solvent were also investigated.
Effects of Laterally and Vertically Neighboring Quantum Dots on Formation of a New Quantum Dot
Authors: Yang Bo , Tewary Vinod K. 
Published: June 2019

AbstractWe apply the elastic-energy-release rate (EERR) to identify the favored location of quantum dot (QD) formation in the presence of a laterally or vertically neighboring grown QD on a linear anisotropic elastic substrate. The EERR is defined as the relaxation energy per unit volume of QD growth. Numerical results for InAs QDs on a GaAs(001) substrate are reported. It is shown that the presence of a laterally neighboring QD inhibits the driving force for the formation of a new QD. In contrast, the presence of a buried (vertically) neighboring QD enhances the driving force for the formation of a new QD at its favorable location.(Publication of the National Institute of Standards and Technology, an agency of the US Government; not subject to copyright.)
Structure of Self-assembled Magnetic FePtCu Nanoparticles Arrays
Authors: Sun Xiangcheng , Harrell J.W. , Nikles D. E. , Sun K. , Wang L. M. , Li J. , Wang Z. L. 
Published: June 2019

AbstractIn this study, a series of FexPtyCu100-x-y nanoparticles were chemically synthesized by solution-phase reduction of platinum and copper reagents and thermal decomposition of iron pentacarbonyl in the presence of stabilizers oleic acid and oleyl amine. As-prepared particles had a chemically disordered face-centered cubic (fcc) lattice with an average diameter of 3.5 nm. The particle size, and the corresponding size distribution were controlled by varying the organic surfactant (oleic acids, etc.), its concentration, and the reaction temperature. These particles were well dispersed in hydrocarbon solvents and self-assembled into two or three dimensions particles arrays with a variety of closepacking arrangements. Domain of monolayers, bilayers and multilayers of particles arrays were frequently detected in TEM specimens. Both cubic close-packed (ccp) and honeycomb arrays were also uniquely observed. It was also demonstrated that the controlled organic surfactant layer (organic capping) play a crucial role in determining assembly dimensions and symmetry as well as particle packing arrays.
Surface patterns of tetragonal phase FePt thin films from Pt@Fe2O3 core-shell nanoparticles using combined Langmuir-Blodgett and soft lithographic techniques
Authors: Guo Qijie , Teng Xiaowei , Yang Hong 
Published: June 2019

AbstractWe present the fabrication of micron-sized patterns of FePt thin films from Pt@Fe2O3 coreshell nanoparticles. In a typical procedure, Pt@Fe2O3 core-shell nanoparticles were spread and formed a Langmuir film using water as the subphase. This film was lifted onto polydimethylsiloxane (PDMS) stamps with micron-sized patterns of lines, dots and wells, and transferred onto silicon wafers using microcontact printing (ν-CP). The patterns of Pt@Fe2O3 core-shell nanoparticles were converted into face-centered tetragonal phase FePt alloy at enhanced temperatures in the presence of 5% hydrogen. Scanning electron microscopy (SEM), atomic force microscopy (AFM), powder X-ray diffraction (PXRD) and superconducting quantum interference device (SQUID) magnetometer were used to characterize the patterns and the properties of the final FePt alloy films.
Electro-optical and Morphological Properties of Bragg Transmission Gratings Written In Holographic Polymer Dispersed Liquid Crystals by Thiol-ene Photopolymerization
Authors: Natarajan L. V. , Tondiglia V. P. , Sutherland R. L. , Tomlin D. , Bunning T. J. 
Published: June 2019

AbstractHolographic Bragg transmission gratings formed via the anisotropic phase separation of nanosized LC droplets (H-PDLC) were fabricated using thiol-ene photopolymerization. Using coherent UV laser light and a single prism, electrically switchable transmission gratings in the Bragg regime were written. The performance of the thiol-ene-based gratings were compared with those of multifunctional acrylate-based gratings written under similar conditions. Optical and electro-optical measurements suggest that thiol-ene polymers offer promise as hosts for improved H-PDLC performance. Interesting differences in the diffraction efficiencies for s– and p-probe beams are noted for the two matrices. Morphology studies by TEM and SEM exhibit striking differences in droplet shape and uniformity. These differences are speculated to be due to differences in polymer MW growth due to the step-growth propagation mechanism for thiol-enes as compared to the chain-growth propagation mechanism in multifunctional acrylates. The response times of the thiol-ene gratings were ten times slower than those of acrylates.
Magnetic Properties of La1-xSrxMnO3 Nanocrystals Embedded in A Mesoporous Silicate
Authors: Kohiki Shigemi , Ishida Yoshihisa , Nogami Sinichiro , Shimooka Hirokazu , Tajiri Takayuki , Deguchi Hiroyuki , Mitome Masanori , Oku Masaoki 
Published: June 2019

AbstractWe have prepared the diluted assemblies of La1-xSrxMnO3 (x = 0, 0.05, 0.15 and 0.175) nanocrystals (ø ∼ 2∼3 nm) embedded in amorphous SiO2 to clarify the nano-magnetism of both the antiferromagnetic and ferromagnetic La1-xSrxMnO3. All the samples of x = 0, 0.05, 0.15, and 0.175 exhibited superparamagnetism with the blocking temperature of ∼40 K. Except the hump at ∼40 K, the antiferromagnetic x = 0 and 0.05 samples showed simply paramagnetic-like characteristics in both the temperature dependent dc and ac susceptibilities. The ferromagnetic x = 0.15 and 0.175 samples demonstrated complicated characteristics in the temperature dependent susceptibilities. The samples indicated antiferromagnetic and ferromagnetic behavior above ∼50 K and ∼100 K, respectively. The field dependent magnetization is consistent with the predictions of systems having randomly oriented and noninteracting fine particles (ø ∼2∼3 nm). For the ferromagnetic La1-xSrxMnO3 nanocrystals, the antiferromagnetism at crystal surfaces suppressed largely the ferromagnetism in bulk.
Normal Incidence Intersubband Transitions in InGaAs/GaAs Quantum Dots With Non-monotonic Shift
Authors: Hussein M. L. , Ma W. Q. , Salamo G.J. 
Published: June 2019

AbstractMultiple layers of self assembled In0.3Ga0.7As quantum dots of different size were grown on GaAs (100) using molecular beam epitaxy. Fourier-transform infrared spectroscopy shows absorption in the long-wavelength infrared region (8–10 νm) under normal incidence. The absorbance peak shift with dot size was investigated and revealed non-monotonic behavior of intersubband transitions. The optical absorption coefficient was calculated to be in order of 3.8×103 cm-2.
Synthesis and Electronic Properties of Single-Crystalline Indium Nitride Nanowires
Authors: Tang Tao , Han Song , Jin Wu , Liu Xiaolei , Li Chao , Zhang Daihua , Zhou Chongwu 
Published: June 2019

AbstractInN nanowires were synthesized and characterized using a variety of techniques. A two-zone chemical vapor deposition technique was employed to operate the vapor generation and the nanowire growth at differential temperatures, leading to high-quality products and growth rates as high as 4–10 μm/hour. The as-grown nanowires showed highly single-crystalline structures and precisely controlled diameters by using monodispersed gold clusters as the catalyst. Devices consisting of single nanowires have been fabricated to explore their electronic transport properties. The temperature dependence of the conductance revealed thermal emission as the dominating transport mechanism.
Large Scale Production of Carbon Nanotube Transistors: A Generic Platform for Chemical Sensors
Authors: Gabriel Jean-Christophe P. 
Published: June 2019

AbstractWe report our work on the fabrication of nanotube-based field effect transistors (NTFET). Nanotubes were grown by chemical vapor deposition using various approaches, including a new formulation of nanotube growth catalysts that were directly patterned using UV lithography. We also report NTFETs based on randomly oriented nanotube networks that have a modulation of one. Finally, we report that a systematical and statistical characterization of millions of devices has led to the development of a robust process that may be useful in large scale production of reproducible, nanotube-based FETs, which, in turn, can be used as a generic platform for chemical sensors.
Quantum Dot-Organic Oligomer Nanostructures: Electronic Excitation Migration and Optical Memory Design
Authors: Javier Artjay , Yun C. Steven , Strouse Geoffrey F. 
Published: June 2019

AbstractEnergy, in the form of an electronic excitation, can be directed within an inorganicorganic composite of semiconductor quantum dots and organic oligomers by manipulating the structural conformations of the organic component or the size of the inorganic component. Continuous-wave and time-resolved photoluminescence studies indicate that weak electromagnetic resonant coupling between discrete intra-chain and inter-chain excitations of the oligomer and quantum dot excitations can be used to produce a potentially useful optical display material. Thin film blends demonstrate a thermally-induced luminescence-detected chainmelting phenomenon that has the potential for writable optical memory.
Synthesis of Gold Nanoshells and Their Use in Sensing Applications
Authors: Sun Yugang , Xia Younan 
Published: June 2019

AbstractA general approach involved template-engaged, galvanic replacement reactions has been developed to prepare metallic nanostructures with hollow interiors by reacting solutions of appropriate salts with metallic solid nanoparticles. The reaction between aqueous chloroauric acid and silver nanoparticles was used as a typical example to demonstrate the synthesis of gold nanoshells. The morphology, void space, and wall thickness of these hollow structures were all determined by the silver templates, which were completely converted into soluble species during the replacement reaction. The extinction peaks of these gold nanoshells were considerably redshifted as compared to solid gold colloids having approximately the same dimensions. In addition, the surface plasmon resonance of gold nanoshells exhibited a much more sensitive response toward environmental changes even when compared with solid colloids with a mean size much smaller than that of gold nanoshells.
Preparation of Inks with Monodisperse Colloidal Silica and their Self-Assembly in a Ink-Jet Printed Droplet
Authors: Ko Hwa-Young , Shin Hyunjung , Moon Jooho 
Published: June 2019

AbstractSemispherical self assemblies of colloids have been fabricated on a substrate using inkjet printing with an ink of submicron-sized monodisperse silica particles. Colloidal silica has been prepared by Stöber process. The shape and monodispersity of the synthesized colloidal particles were observed by scanning electron microscopy (SEM) and laser light scattering particle analyzer. Simple test patterns on various substrates (silicon wafer, Cu foil, and Mylar film) were printed with commercial HP printer. It was found that the uniformity and spatial extent of the self-assembled colloidal silica within a dot were significantly influenced by the contact angle between ink and substrates. Ink droplets printed on the hydrophobic Mylar film maintain a higher contact angle as compared to the hydrophilic substrates such as Si wafer. Slower evaporation and high capillary stress exerted on the ink droplet allow hemispherical colloidal aggregates with an ordered internal structure on Mylar film.
Selfassembling around Templates – Creating Nano Dots and Pits for Chemical Sensing –
Authors: Dickert Franz L. , Lieberzeit Peter A. , Hayden Oliver , Bindeus Roland , Mann Karl-Jürgen , Haderspöck Claudia 
Published: June 2019

AbstractNano- and micro-structured materials are a powerful tool in the development of chemical sensors. Surface imprinting of different biogenous species into pre-polymerized, highly crosslinked reaction mixtures (polyurethanes, polystyrenes, sol-gel materials etc.) yields selfassembled structures that are optimized to re-incorporate the template particle. Surface properties are tuned both on the micrometer as well as the molecular scale, as selectivity studies suggest the formation of strongly adapted interaction networks between the polymer and the species used for imprinting.
Catalytic Growth of Semiconducting ZnO Nanowires by Reactive Evaporation Process
Authors: Park Joodong , Choi Han-Ho , Singh Rajiv K. 
Published: June 2019

AbstractReactive evaporation process was introduced as a simple technique for the fabrication of aligned ZnO nanowires on a Si (100) surface. Single crystalline ZnO nanowire arrays were successfully synthesized on Au coated Si substrates via a VLS growth mechanism. The diameter of ZnO nanowires were observed to vary from 40 nm to 150 nm and the ratio of length to diameter was observed to be larger than 30. The diameter of ZnO nanowires was controlled by changing the processing temperature and by the thickness of Au catalyst film. Green emission induced from singly ionized oxygen vacancies was generated from ZnO nanowires with the excitonic emission in UV range. Higher intensity of the green emission was observed in thinner nanowires, which is attributed to their higher surface-to-volume ratio. Aligned structure formation and size control of ZnO nanowires could provide the potential for various nano-scale device applications.