The paper describes a novel electrochemical method of metal nanowire synthesis via coherent cocrystallization of metal with metal salt. Using the method described, iron, copper, and tin nanowires as well as lead nanowalls in the matrix of ferrous chloride FeCl2 salt were synthesized. Influence of electrolyte composition and electrolysis regime on the deposit structure is revealed. Morphology, chemical composition, and structure of the NW@salt nanocomposite is studied and discussed.

We performed dynamical cluster analysis in a Cu-Zr-Al based glass-forming metallic liquid using an unsupervised machine learning algorithm. The size of the dynamical clusters is used to quantify the onset of cooperative dynamics as the underlying mechanism leading to the Arrhenius dynamic crossover in transport coefficients of the metallic liquid. This technique is useful to directly visualize dynamical clusters and quantify their sizes upon cooling. We demonstrate the robustness of this algorithm by performing sensitivity analysis against two key parameters: number of mobility groups and inconsistency coefficient of the hierarchical cluster tree. The results elucidate the optimized range of values for both of these parameters that capture the underlying physical picture of increasing cooperative dynamics appropriately.

Lenses in laparoscopes, arthroscopes, and laryngoscopes fog during closed body surgery due to humidity from bodily fluids and differences between body and operating room temperatures.1,2 Surgeons must repeatedly remove, clean, and reinsert scopes that are obscured by fog. As a result, surgery duration, infection risks, and scarring from air exposure increase.3,4 Current methods to address fogging introduce other complications. Acidic alcohol-based coatings scar tissue and quickly evaporate, and heated lenses require reheating every 5 to 20 minutes.3,4 This paper presents a new super-hydrophilic, biocompatible, non-toxic, pH neutral (7.2-7.4), and long-lasting anti-fog coating called VitreOx™.5-7 VitreOx™ can be used wet or dry, without use of alcohol, heat, or fluid evacuation. When applied as a liquid, it easily espouses lenses’ surfaces and edges, and dries within seconds to form a permanently super-hydrophilic surface on silica and polymer surfaces. VitreOx™ avoids current shortfalls by eliminating frequent reapplications, avoiding reapplication for surgeries lasting up to 72 hours.

VitreOx™'s anti-fog properties can be explained by nucleation and growth theory for thin films condensation: 1) 3-D droplets, resulting in fogging; 2) 2-D sheets resulting in a flat transparent film; or 3) mixed 3-D on 2-D, resulting in optical distortion. On hydrophobic surfaces (e.g. lenses), condensation occurs with fogging via spherical 3-D droplets, as in the Volmer-Weber model. 3-D droplets scatter light in all directions through refraction yielding opaque or translucent films (fog). VitreOx™ applied to hydrophobic lenses renders them super-hydrophilic. Similar to the 2-D Frank Van-der-Merwe Growth Mode, condensation with uniform wetting yields transparent 2-D films that do not distort optical images transmission.

In vitro and in vivo studies of VitreOx™ were conducted to measure performance and duration of anti-fog effectiveness and bio-compatibility. In vitro tests spanned from 3 to 72 hours over a 3-year range. Side-by-side in vivo gastro-endoscopies were conducted on Yucatan™ swine for 90 minutes using 1) VitreOx™, 2) bare lens, and 3) Covidien Clearify™ surfactant with warmer. VitreOx™ coated lenses did not fog nor need reapplication for 90 minutes, while Covidien Clearify™ lasted 38 minutes without fogging, requiring retreatment. No adverse reaction was observed on swines exposed toVitreOx™, in surgery and 12 months thereafter.

Effects of defect on ferroelectric stability in PbTiO3 (PTO) thinfilms have been investigated using molecular dynamics with first-principleseffective Hamiltonian. In this paper, oxygen vacancy (Vo) has been considered tostudy the hysteresis loop, spontaneous polarization as a function of filmthickness. Vo has been modeled as a charged point defect. Density functionaltheory (DFT) calculations are performed to determine the Vo-induced localizedfields (both mechanical and electrical) and the calculated DFT results are usedas inputs to molecular dynamics simulations in a large system. The strain fieldinduced by the Vo is calculated by DFT calculations and fitted by the continuumstrain modeling, and the electrostatic field is given by the superposition ofthe Vo-induced field and the external field. Vo significantly reduces thespontaneous polarization and increases the critical thickness.

TlBr crystals have superior radiation detection properties; however, their properties degrade in the range of hours to weeks when an operating electrical field is applied. To account for this rapid degradation using the widely-accepted vacancy migration mechanism, the vacancy concentration must be orders of magnitude higher than any conventional estimates. The present work has incorporated a new analytical variable charge model in molecular dynamics (MD) simulations to examine the structural changes of materials under electrical fields. Our simulations indicate that dislocations in TlBr move under electrical fields. This discovery can lead to new understanding of TlBr aging mechanisms under external fields.

Poly(ε-caprolactone) (PCL) biopolymer nano- and micro-fibers have been fabricated at high rates up to 14.0 grams per hour using a needleless and collectorless alternating current electrospinning technique. By combining the ac-voltage, glacial acetic acid (AA) as the solvent and sodium acetate (NaAc) as an additive, beadless PCL fibers with diameters tunable from 150 nm to 2000 nm, varying surface morphology and degree of self-bundling were obtained. In this new approach, the addition of NaAc plays a crucial role in improving the spinnability of PCL solution and fiber morphology. NaAc revealed the concentration-dependent effect on charge transfer and rheological properties of the PCL/AA precursor, which results in broader ranges of spinnable PCL concentrations and ac-voltages suitable for rapid manufacturing of PCL-based fibers with different textural properties.

To achieve the goal of biocompatibility in nano-based materials we must first obtain a fundamental understanding of the physical and chemical behavior of biomolecules at the interfaces of nanomaterials. A first step towards understanding protein interactions with nanomaterials is to understand how individual amino acids interact at the interfaces. In this paper, we investigated the lysine adsorption behavior on fumed silica nanoparticles by solid-state NMR spectroscopy. We use 1H, 13C and 15N solid-state magic angle spinning (MAS) NMR techniques to elucidate how lysine is adsorbed on silica nanoparticles surfaces via strong hydrogen-bonding interaction between the protonated side-chain amine group and silanol group on silica nanoparticles surfaces.*

Zero Valent Iron nanoparticles (nZVI) were synthesized and immobilized on electrospun carbon nanofibers (ECNFs) surface in a controllable manner through redox reaction. The novel nanomaterial, ECNFs-supported nZVI (nZVI@ECNFs), were evaluated for Cr(VI) ions removal from water for the first time. nZVI@ECNFs outperformed stand-alone nZVI as well as state-of-the-art nZVI research for Cr(VI) remediation in water. nZVI@ECNFs with 0.4 g/L nZVI loading could remove 100% Cr(VI) from 50 mg/L Cr(VI) aqueous solution in as little as 5 min at pH = 4. This is enabled by coupling nanofibrous form ECNFs with dispersed distribution of individual and/or cluster nZVI on surface of ECNFs. It is envisioned that nZVI@CNFs is going to serve as a novel supported nZVI nanomaterial for super-fast heavy metal remediation in ground water and waste water treatment with adjustable high capacity as well as straightforward and energy-saving heavy metal recovery.

To measure the Raman scattering spectrum of a monolayer graphene sample, we describe the design and development of a high-efficiency optical measurement device for operation within the small bore of a high-power magnet at low temperature. For the high-efficiency measurement of light emitted from this small region, we designed a compact confocal optics with lens focusing and tilting systems, and used a piezodriven translation stage that allows micron-scale focus control of the sample position. In addition, we show a detailed technique of adjustment of optical axes, and explain the importance of the focusing and tilting systems. The operation of the device was confirmed by Raman scattering measurements of monolayer graphene on quartz glass with a high signal-to-noise ratio. Though the light collection efficiency of the device is about 240-fold smaller than that of a conventional optical microscope, the device has a sufficient collection efficiency for detecting the Raman scattering light of monolayer graphene.

2D materials have shown to be the next step in semiconductor use and device manufacturing that can allow us to reduce the size of most electronics. One of the novel ways to obtain 2D materials is through liquid exfoliation, in which these materials can be obtained by dispersing the smallest possible particles in different solvents. Once obtained, the solutions can be used to manufacture devices via different processes, one of which is inkjet printing. This process relies in selecting “jettable” fluids, which need to have the necessary combination of viscosity and surface energy or “wettability”. In this work we have modified the viscosities and surface energies of five solvents: IPA (Isopropanol), NMP (N-methyl – 2 pyrrolidone), DMA (Dimethylacetamide), DMF (Dimethylformamide) and a mixture of Cyclohexanone / Terpineol 7:3. We have found an avenue to tailor the viscosity of these solvents though the addition of Ethyl Cellulose (EC), where the viscosity has been increased by up to 15 times at an EC concentration of 6%. For inkjet printing, ideally a viscosity of 4 – 10 cP is recommended, which we have been able to achieve with all of the solvents studied. It has been found that the different solvents present different susceptibilities to the EC addition, with DMA and DMF being the least sensitive to the EC addition. We have also studied the change in the drop dynamics and interactions of the 2D solutions with the substrate. Through this analysis we have found solvents that appear to be attractive for inkjet printing of MoS2 and graphite.

We present a thermodynamically consistent phase-field model describing the free energy of perovskite-based BCT-BZT solid solution containing an intermediate morphotropic phase boundaries. The Landau coefficients are derived as functions of composition of zirconium. The electrostrictive and elastic constants are appropriately chosen from experimental findings. The resulting Landau free energy is constructed to describe the stable polarization states as a function of composition. The evolution of the polarization order parameters at a particular composition is described by a set of time-dependent Ginzburg-Landau (TDGL) equations. Additionally, we solve Poisson’s equation and mechanical equilibrium equation to account for the ferroelectric/ferroelastic interactions. We have performed two dimensional and three-dimensional simulations with appropriate electrical boundary conditions to study the effect of external electric field on domain dynamics in BCT-BZT system at the equimolar composition.

Compositional imaging of several immiscible polymer blends was examined with the combination of AFM-based mechanical and electric modes with chemically-specific Raman mapping. Results showed that these methods substantially complement each other in comprehensive characterization of surface morphology by helping to identify a composition of top surface and sub-surface materials in polymer heterogeneous systems.

Silicon Photonics is the technological to face the future challenges in data communications and processing. This technology follows the same paradigm as the technological revolution of the integrated circuit industry, that is, the miniaturization and the standardization. One of the most important building blocks in Silicon Photonics is the microresonator, a circular optical cavity, which enables many different passive and active optical functions. Here, we will describe the new physics of the intermodal coupling, which occurs when multi radial mode resonators are coupled to waveguides, and of the optical chaos, which develops in coupled sequence of resonators. In addition, an application of resonators in the label-free biosensing will be discussed.

Spectroscopic imaging and statistical analysis of NIR-to-visible upconversion luminescence (UCL) from β-NaYF4:Yb3+:Er3+ upconverting nanoparticles (UCNPs) supported on a series of random Ag nanowire aggregates reveals a density dependent UCL enhancement. Statistical analysis of the spectrally resolved upconversion images shows a non-linear dependence of upconversion luminescence enhancement with Ag nanowire surface coverage. A maximum average enhancement of 5.8× was observed for 58% surface coverage. Based on the empirically determined trend with density, it is estimated that up to 20× upconversion luminescence enhancement can be achieved at 100% surface coverage, even at high excitation intensity. This projection is commensurate with the 20× enhancement ratio observed for select locations within the imaged micro-ensemble. Time-resolved emission of the UC luminescence from UCNPs on the Ag nanowire aggregates confirms the surface plasmon effects on the UCNPs kinetics. Such Ag nanowire aggregates show potential as a scalable and relatively simple metal-enhanced upconversion substrate.

In the previous work, it is reported that the Spin-Seebeck effect (SSE), which refer to the generation of a spin current from a temperature gradient, can be enhanced by Fe interface treatment. Here, we investigated the Fe thickness (dFe) dependency of spin-Seebeck voltage (VSSE) and mixing conductance (gr) in Pt/Fe/Bi:YIG/SGGG system. As a result, magnitude of VSSE had a peak at dFe ≓ 1 ML (monolayer , ≓ 0.3 mm), and also increase of gr was saturated at this point. It suggests that VSSE increase with increasing gr when dFe is smaller than 1.0 ML. For the case in which dFe is larger than 1.0ML, however, VSSE decreases due to a spin current decay in Fe layer with a constant gr. These experimental results are consistent with previous theoretical works.

The crystal structure and phase transformations of iron sulfide nanomaterialshave interesting properties that can be utilized in solar cells, biological andother applications. Iron (III) complexes piperidine (1) andtetrahydroquinoline (2) dithiocarbamate have been synthesized andsubsequently utilized as single source precursors for the preparation of ironsulfide nanoparticles by solvothermal and pyrolysis methods. The powder X-raydiffraction (p-XRD) studies gave crystalline information of the iron sulfidenanoparticles which were dependent on the reaction conditions. Only the greigitephase (Fe3S4) was obtained when the solvothermal methodwas used during the synthesis. The pyrolysis method gave a mixture of pyrite(FeS2) and pyrrhotite phases when complex (1) wasused while complex (2) gave pure pyrrhotite. Well interconnectedmicrostructures and nanoflakes-like structures were obtained by scanningelectron microscopy imaging. Furthermore, magnetic properties of theas-synthesized nanoparticles displayed ferromagnetic and antiferromagneticbehaviour, typical of greigite and pyrrhotite nanoparticles respectively. Adirect band gap of 2.70 eV was obtained according to optical absorptionstudies.

Immobilization into 3D matrices stabilizes proteins in comparison to flat planarsurfaces and facilitates the study of the biomolecular interactions as well asintegration into optrodes for cell physiology. Photocrosslinkable hydrogels havereceived significant attention in recent years as they provide not only a highlyhydrophilic 3D environment to promote protein stabilization and its interactionswith analyte molecules, but enable optically addressable patterning for spatialcontrol of protein localization. At the same time, the explosion of newgenetically encoded sensor proteins has greatly expanded the range of opticalmolecular sensors for cell physiology. Here we integrate a genetically encodedglutamate sensor protein into a photocrosslinkable hydrogel via covalentinteraction to create a novel glutamate sensor material. Protein immobilizationcan be achieved through covalent bonds, physical interactions, or physicalentrapment. Although physical entrapment without chemical modifications offers auniversal approach for protein immobilization, leaching of protein through thepores of the hydrogel is a significant challenge. Thus, here an alternativemethod is developed to provide better control of protein localization andimmobilization using naturally existing reactive groups of proteins. To thisend, a genetically encoded FRET based glutamate indicator protein (FLIPE) ismodified with diacrylated poly (ethylene glycol) (PEGDA) by Michael-typeaddition between acrylate groups and the thiol side chains of the cysteineresidues. We optimize the molecular weight of PEGDA (300, 740, and 3400 Da) aswell as concentrations of the photoinitiator (0.1, 0.5 and 1 % (w/w)) andmonomer (10, 20, and 30 % (w/w)) in the precursor solution. Next the precursorsolution is grown at the distal end of an optical fiber to test thespectroscopic properties and characteristic bioactivities of proteins in thehydrogel network. Optimization of the irradiation parameters, light intensityand exposure time, improves the spatial resolution of 3D hydrogel tips. Thisstudy examines the capability of fabricating 3D hydrogel sensors covalentlymodified with a member of recently growing genetically encoded fluorescentbiosensors, which can later be extended to all conformation-dependent proteinbiosensors and be used intracellularly for physiological and biological sensingpurposes.

Pulsed laser deposition (PLD) is a technique which utilizes a high energy pulsed laser ablation of targets to deposit thin films on substrates in a vacuum chamber. The high-intensity laser pulses create a plasma plume from the target material which is projected towards the substrate whereupon it condenses to deposit a thin film. Here we investigate the properties of vanadium oxide thin films prepared utilizing two variations of the pulsed laser deposition (PLD) technique: femtosecond PLD and nanosecond PLD. Femtosecond PLD (f-PLD) has a significantly higher peak intensity and shorter duration laser pulse compared to that of the excimer-based nanosecond PLD (n-PLD). Experiments have been conducted on the growth of thin films prepared from V2O5 targets on glass substrates using f-PLD and n-PLD. Characterization using SEM, XRD and Raman spectroscopy shows that the f-PLD films have significantly rougher texture prior to annealing and exhibit with an amorphous nano-crystalline character whereas the thin films grown using n-PLD are much smoother and highly predominantly amorphous. The surface morphology, structural, vibrational, and chemical- and electronic-state elemental properties of the vanadium oxide thin films, both prior to and after annealing to 450 °C, will be discussed.

The kinetics of Ge lateral overgrowth on SiO2 with line-shaped Si seeds is examined. The growth process is described by the difference between the growth rates of Ge on (100) planes (GR100) and <311> facets (GR311). The theoretical calculations well reproduce the growth kinetics. It is shown that narrowing the line-seeds helps Ge coalescence and flat film formation.

The paper presents the research results of influence of various parameters of magnetic field concentrator geometry on sensitivity of magnetically controlled MEMS switches. It is shown that magnetic sensitivity increases with the growth of the magnetic concentrator width and practically does not depend on its length. It is established that dependence of magnetic sensitivity on the overlap length of the ferromagnetic flexible contact-concentrator has a minimum corresponding to 2-3 lengths of the contact gap. Recommendations on sensitivity increase of magnetically controlled MEMS switches are provided.