Nanoparticle Sheets Research Articles

Study of hybrid nanofluid flow in a porous medium over an exponentially stretching sheet under Joule heating and thermal radiation: Finite difference

The significant purpose of present investigation of the behavior of a nanofluid's in magneto-hydrodynamics (MHD), mass transfer, Joule heating, and boundary layer transfer characteristics over an exponentially stretching sheet in a porous medium and thermal radiation effects. The article's goal is to look at the fluid flow and heat transmission characteristics from a sheet of hybrid nanoparticles. The partial differential equations (PDEs) that were derived for the mathematical model were converted using the proper similarity transformation into ordinary differential equations (ODEs). The hybrid nanofluid composed of 97 % of ethyl glycol (EG) and the volume concentration of Magnetite (Fe3O4) and Copper(Cu) are ranging from 0.5 % to 2.5 % both respectively. The effects of thermal radiation, stretching rate, Joule heating, porous medium permeability, and nanoparticle volume fraction on the flow and heat transmission properties are investigated by numerical simulations using the finite difference method (FDM). The analysis reveals that the inclusion of nanofluids enhance the thermal conductivity and enhance the heat transfer rate. Additionally, the influence of variable viscosity on the flow behavior and thermal characteristics are examined graphically. The effects of variable viscosity and thermal conductivity are examined, as it has significance in optimizing system under various thermal and magnetic effects. This study offers a pathway to develop more efficient thermal management solutions, by contributing to technological advancement and energy saving. The key findings of present study reveal that the temperature profile rises significantly due to Joule heating effects. The Nusselt number reveal an improvement of about 12 % when the volume fraction of nano particles is increased by 1–4 % indicating the enhancement in heat transfer efficiency. Similarly, the velocity profile was influenced by porous medium permeability as 11 % increase in porosity result a 18 % decrease in velocity profile.By using parametric research, the role of physical parameters in determining the local skin-friction coefficient, temperature, nanoparticle volume percentage, and longitudinal velocity profiles, local Nusselt number, and local Sherwood number are thoroughly examined. A graphic representation of the velocity, temperature, and concentration distribution findings is presented.

Analysis of thermal conductivity variation in magneto-hybrid nanofluids flow through porous medium with variable viscosity and slip boundary

Hybrid nanoparticles, which are nanoparticles composed of multiple materials or phases, find applications in various fields due to their unique properties resulting from the combination of different materials. In such fluids, viscosity changes significantly in response to alterations in temperature or pressure. For example, these fluids become less viscous as they are heated and more viscous as they are cooled. Similarly, in certain situations, the application of a temperature variation can cause a change in viscosity. This property is commonly observed in materials like polymers and some oils. The article aims to investigate the heat transfer and flow behavior of fluid from an elastic sheet of hybrid nanoparticles, considering the temperature-dependent variable viscosity and thermal conductivity. The obtained equations for the mathematical model are partial differential equations converted to ODEs by applying a suitable similarity transformation. The findings show that the magnetic field opposes fluid motion. Our main findings are that adding nanoparticles to the base fluid significantly increased its heat conductivity. This improvement has great potential for uses requiring effective heat transmission, especially in engineering systems where heat dissipation plays a crucial role. The study also reveals the complex relationships that influence thermal conductivity, including slip boundary effects, viscosity fluctuations, magnetohydrodynamic effects, and porous media dynamics. Understanding these interactions is critical for optimizing heat transport processes in porous media applications. Comprehending these interplays is essential for refining heat transport mechanisms in applications involving porous media. The graphical representations are used to explain the physical behavior of various model parameters. Previous outcomes are also contrasted with the current ones. The findings show that the magnetic field opposes fluid motion.We range the subsequent list of values for parameters in every graph unless indicated accordingly.ϵ=0.1,Pr=2,M=0.5,R=0.2,K=5,fw=0.1,s=0.1 ,λ=1,φ1=0.02,φ2=0.04.

Innovative approach: utilizing silver nanoparticles sheet for improved rabbit cecal anastomosis healing.

Anastomotic leakage is a severe complication associated with gastrointestinal surgery. The process of intestinal wound healing is crucial for the successful outcome of digestive tract surgical repair procedures. This research aimed to determine the impact of silver nanoparticles sheet (Acticoat) on the anastomotic healing of the cecum in rabbits. A total of 48 New Zealand male rabbits in good health were used for cecum transection and anastomosis. The animals were randomized into the control group (C) and the silver nanoparticles group (AgNPs). In the C group, the transected cecum was end-to-end anastomosed with a single layer of simple continuous suture pattern using 3-0 polyglyconate. In contrast, a silver nanoparticle sheet (Acticoat) was covered around the sutured anastomotic line in the AgNPs group. Postoperatively, abdominal ultrasound imaging and the Bristol Rabbit Pain Score (BRPS) were measured on days 7, 15, and 30. Eight rabbits from each group were euthanized at each time point to assess macroscopic findings, bursting pressure tests, tensile strength tests, histopathological examinations, and immunohistochemical analyses. The AgNPs group demonstrated a significant increase in the cecal lumen diameter wall (p ≤ 0.001), burst pressure measurement (p ≤ 0.02), and tensile strength (p ≤ 0.01). Conversely, the AgNPs group had significantly lower BRPS scores (p ≤ 0.01). In addition, histopathological examinations revealed that AgNPs significantly reduced inflammatory cell infiltration (neutrophils and macrophages) and enhanced collagen deposition. Immunohistochemical analyses revealed a significant increase (p ≤ 0.01) of α-SMA and a reduction of CD31 in the anastomotic tissue of the AgNPs group. The results of the present study indicate that the utilization of the AgNPs sheet (Acticoat®) effectively enhanced the strength of cecum anastomosis, resulting in a reduction in anastomosis leakages, pain scores, and abdominal adhesions. Additionally, the bursting pressure values in the rabbit model were significantly increased.

Morphology Controlled Deposition of Vanadium Oxide (VOx) Nanoparticles on the Surface of Highly Reduced Graphene Oxide for the Photocatalytic Degradation of Hazardous Organic Dyes.

Semiconducting nanomaterials based heterogeneous photocatalysis represent a low-cost, versatile technique for environmental remediation, including pollution mitigation, energy management and other environmental aspects. Herein, we demonstrate the syntheses of various heterogeneous photocatalysts based on highly reduced graphene oxide (HRG) and vanadium oxide (VOx)-based nanocomposites (HRG-VOx). Different shapes (rod, sheet and urchin forms) of VOx nanoparticles were successfully fabricated on the surface of HRG under solvo-/hydrothermal conditions by varying the amount of water and ethanol. The high concentration of water in the mixture resulted in the formation of rod-shaped VOx nanoparticles, whereas increasing the amount of ethanol led to the production of VOx sheets. The solvothermal condition using pure ethanol as solvent produced VOx nano-urchins on the surface of HRG. The as-prepared hybrid materials were characterized using various spectroscopic and microscopic techniques, including X-ray diffraction, UV-vis, FTIR, SEM and TEM analyses. The photocatalytic activities of different HRG-VOx nanocomposites were investigated for the photodegradation of methylene blue (MB) and methyl orange (MO). The experimental data revealed that all HRG-VOx composite-based photocatalysts demonstrated excellent performance toward the photocatalytic degradation of the organic dyes. Among all photocatalysts studied, the HRG-VOx nanocomposite consisting of urchin-shaped VOx nanoparticles (HRG-VOx-U) demonstrated superior photocatalytic properties towards the degradation of dyes.

Large emergent optoelectronic enhancement in molecularly cross-linked gold nanoparticle nanosheets

A central goal in molecular electronics and optoelectronics is to translate tailorable molecular properties to larger materials and to the device level. Here, we present a method to fabricate molecularly cross-linked, self-assembled 2D nanoparticle sheets (X-NS). Our method extends a Langmuir approach of self-assembling gold nanoparticle (NP) arrays at an air-water interface by replacing the liquid sub-phase to an organic solvent to enable cross-linking with organic molecules, and then draining the sub-phase to deposit films. Remarkably, X-NS comprising conjugated oligophenylene dithiol cross-linkers (HS-(C6H4)n-SH, 1 ≤ n ≤ 3) exhibit increasing conductance with molecule length, ~6 orders of magnitude enhancement in UV-Vis extinction coefficients, and photoconductivity with molecule vs. NP contributions varying depending on the excitation wavelength. Finite difference time domain (FDTD) analyses and control measurements indicate that these effects can be modeled provided the local complex dielectric constant is strongly modified upon cross-linking. This suggests quantum hybridization at a molecule–band (q-MB) level. Given the vast number of molecules and nano-building blocks available, X-NS have potential to significantly increase the range of available 2D nanosheets and associated quantum properties.

Structural, electrical and optical properties of MgO-reduced graphene oxide nanocomposite for optoelectronic applications

MgO-reduced graphene oxide nanocomposites (NCs) were synthesized by a simple two-step chemical method. The microstructure, surface morphology, and composition of the prepared samples have been studied. X-ray diffractometer (XRD) analysis confirmed the crystalline cubic MgO nanoparticle and rGO sheets. Scanning electron microscope (SEM) showed the spherical MgO nanoparticles well dispersed over the graphene sheets. UV–visible spectroscopy analysis demonstrated that a red shift in the wavelength dependent absorbance curve. The band gap of the samples was found to be decreased with the increase of rGO content. The dielectric studies have been examined in the frequency range 500 Hz−5 MHz and found significant improvement in the dielectric constant, dielectric loss, and electric properties due to rGO addition.This is mainly attributed to the strong interfacial polarization (Maxwell–Wagner polarization) between MgO and rGO sheets. Further, the modulation of charge carrier density with rGO additions help to enhance the electrical conductivity of NCs and thus, encouraging to have wider application in electronic and energy technologies.

Paper‐Like Writable Nanoparticle Network Sheets for Mask‐Less MOF Patterning

AbstractGeometrical structuring of monolithic metal‐organic frameworks (MOFs) components is required for their practical implementation in many areas, including electronic devices, gas storage/separation, catalysis, energy storage as well as bio‐medical applications. Despite progress in structuring MOFs, an approach for the precise patterning of MOF functional geometries in the millimeter‐ to micro‐meter depth is lacking. Here, a facile and flexible concept for the microfabrication of complex MOF patterns on large surfaces is reported. The method relies on the engineering of easily‐writable sheets of precursor metal oxide nanoparticles. The gas‐phase conversion of these patterned ceramic nanoparticle sheets results in monolithic MOF objects with arbitrarily shaped geometries and thicknesses of up to hundreds of micrometers. The writing of complex patterns of zeolitic imidazolate framework‐8 (ZIF‐8) is demonstrated by a variety of approaches including ion beam, laser, and hand writing. Nanometer‐scale patterns are achieved by focused ion beam (FIB). Artless handwritings are obtained by using a pen in a similar fashion to writing on a paper. The pure ZIF‐8 composition of the resulting patterns is confirmed by a series of physical and chemical characterization. This facile MOF precursor‐writing approach provides novel opportunities for the design of MOF‐based devices with applications ranging from micro‐fluidics to renewable energy systems.

Chiral Metal Nanoparticle Superlattices Enabled by Porphyrin‐Based Supramolecular Structures

AbstractHerein, we show that chiral metal nanoparticle superlattices can be produced through coassembly of achiral metal nanoparticles and porphyrin‐based organic molecules. This chirality transfer from molecules to nanoparticle superstructures across three orders of magnitude in length scale is enabled by the hetero chain‐chain van der Waals interactions. As far as we know, these are the first chiral nanoparticle assemblies based on chirality transfer through weak van der Waals forces. The dimensionality of the nanoparticle superlattices (1D chiral chains, 2D chiral sheets (cones), and 3D chiral particles) can be controlled based on a same synthetic chiral porphyrin molecule. Metalation of these porphyrin molecules with zinc cations results in the switching of molecular packing from J‐type to H‐type, which thereby produces 1D chiral nanoparticle chains. Functionalization of these zinc porphyrins with oleylamine can induce the assembly of nanoparticles into 2D chiral nanoparticle sheets.

Investigation of the Effect of Sonication Time on Dispersion Stability, Dielectric Properties, and Heat Transfer of Graphene Based Green Nanofluids

Natural ester oils are the current target of many industries and electrical utilities as electrically insulating fluids to replace the conventional mineral oils. However, as previously investigated, most natural ester oils are based on edible products, causing a negative impact on the food crisis. Accordingly, nonedible green nanofluids based on cottonseed oil have been targeted in the present study. Additive graphene nanoparticles (0.0015 wt%, 0.003 wt%, 0.006 wt%, and 0.01 wt%) along with surfactant sodium dodecylbenzene sulfonate (SDBS) were used (1:1) due to their promising impact on dielectric and thermal properties. Experimental methods introduced were including characterization of graphene and preparation of dielectric nanofluids (DNFs). The main concern for any nanofluid to be usable in transformer applications is its long-term stability. The effect of various ultrasonication periods (10, 20, 30 and 60-minute) on short-term stability of nanofluids was preliminary investigated by visual inspection, highest short-term stability was obtained at 30-min and 60-min. Considering short-term stability results, the two most stable samples were investigated and compared for long-term stability through ultraviolet-visible (UV-Vis) spectroscopy to find the suitable ultrasonication time. In addition, dielectric and thermal properties of these samples were investigated and compared. Physical mechanisms were discussed for the obtained enhancements considering the effect of ultrasonication period on the number of dispersed nanoparticle sheets per unit volume and the corresponding effect on dielectric and thermal properties.

Graphene nanoparticles-based ELISA as a crucial new diagnostic tool for diagnosis of human filariasis

Background: Filariasis is a disease caused by filarial parasitic worms, which are microscopic roundworms that live in the blood and tissues of humans. Graphene oxide (GO) sheets are excellent nano carriers in many analytical methods. In this study, a modified enzyme-linked immunosorbent assay (ELISA) strategy was developed using antibody-functionalized GO sheets. This modification significantly reduced the limit of detection (LOD) and cost greatly of this assay. Serum samples from infected individuals were collected from different Governorates in Egypt. Methods & Materials: The microfilarial status of the individuals was assessed by membrane filtration followed by visualization under a light microscope Sera were collected after informed consent from 27 microfilaremic patients (MF), 21 with chronic lymphatic disease (CL), and 20 microfilariae negative healthy individuals residing in the nonendemic areas, in parallel sera from 20 other parasites infected patients were collected. All these persons were subjected to the following after their concent; history taking, clinical examination and laboratory investigations which included: examination of blood samples for microfilaria using thick blood film and serological tests for detection of the circulating filarial antigen (CFA) using monoclonal antibody based Og4C3 commercial kit ELISA, classical recommended mapping tool (ICT test) and grapheme nanoparticles-based ELISA Results: None of the 20 non-endemic normal sera were positive for filarial antigen indicating the specificity of commercial kit ELISA. In contrast, 23/27 microfilaraemic sera, 7/21 chronic lymphatic patients sera showed the presence of filarial antigen. Based on ICT 18/27 microfilaraemic sera, 9/21 chronic lymphatic patients sera showed the presence of filarial antigen. Using GO sheets nanoparticles-based ELISA 25//27 microfilaraemic sera, and 6/21 chronic lymphatic patients sera showed the presence of filarial antigen. Conclusion: In conclusion, GO nanoparticle sheets are excellent nano analytical methods using a modified enzyme-linked immunosorbent assay (ELISA) strategy for diagnosis of human filariasis.

Thermal conductivity variation and heat generation effects on magneto-hybrid nanofluid flow in a porous medium with slip condition

ABSTRACT The application of hybrid nanoparticles rather than nanoparticles is one of the greatest critical tasks for enhancing heat transfer. Therefore, the purpose of this article is to analyze the flow and heat transfer resulting from an exponentially decreased sheet of hybrid nanoparticles. The magnetite (Fe3O4) and copper (Cu) nanoparticle are suspended in ethylene glycol (EG) to form Fe3O4–Cu/EG hybrid nanofluid. The PDEs governing equations of the issue have been solved after conversion to ODEs by using suitable similarity transformations. The resultant system is then solved numerically by the aid of Runge–Kutta–Fehlberg method (RKF45) with the shooting technique. The most important results of this study are the effect of different variable parameters such as permeability of porous media, the stretching/shrinking parameter, heat generation/absorption effect, slip, and nanoparticle volume fraction on the velocity, temperature profiles, skin friction coefficient, and local Nusselt number. Furthermore, the impacts of radiation, magnetohydrodynamic (MHD), suction/injection parameter, and Prandtl number are also taken into consideration. The influence of important physical parameters is discussed through graphs and tables. It is found that the increase of Fe3O4 nanoparticle concentration enhances the heat transfer rate of the hybrid nanofluid in a shrinkable case, the opposite happens in a stretchable state.

Iron-based nanomaterial sheets for electromechanical applications

Now a day's Single-Walled Carbon nanotubes (SWCNTs) having the greatest attention on the earth. This area favors a 2-D graphene sheet configurationally which is rolled up into a hollow cylindrical structure. Having just one surface or wall of the cylinder, the cylindrical formation is named as Single-Walled Carbon Nanotubes. The structure appears sort of a set of cylinders having the same center with a continuing layer separation of 0.34 Å termed as multi-walled carbon nanotubes. A mixture of Nanopowder of iron oxide and a blend of Single-Walled Carbon Nanotubes provides great promising properties towards the Electromechanical applications by enhancing their electrical and mechanical properties. In this paper, we will discuss the characteristics and behavior of the newly synthesized nanoparticle sheet whose major constituent is iron. This paper will also explore the advantages and disadvantages of the conventional Iron sheets used in electromechanical applications. for synthesizing the nano iron sheets, among different methods we used the nano-emulsion method in which we mixed two nanoparticles in a different phase to get the desired result.

In-situ ionothermal precipitation of well-dispersed ZnO nanoparticles onto 2-dimension neat graphene sheets with excellent photocatalytic activity

Neat graphene (NG) is rarely selected as a support to improve the photocatalytic performance of metal oxides due to its extremely poor processability in aqueous solutions. In this study, an in-situ ionothermal precipitation was developed to fabricate ZnO nanoparticle and few-layered NG sheet nanohybrids (ZnO/NG) in one-pot. Choline chloride/diethylene glycol-based deep eutectic solvent was used as reaction medium to dissolve the zinc salt precursor and disperse graphene. XRD, Raman, XPS and TEM analyses showed that ZnO particles with sizes of 15–25 nm were uniformly dispersed on the graphene sheets and a bond of ZnOC was formed between the interfaces. The UV–vis diffuse reflectance spectra measurement exhibited that the incorporation of graphene slightly narrowed the bandgap of ZnO nanoparticles, but significantly enhanced the light absorption of the nanohybrids in the visible range. Photocatalytic degradation of methylene blue dye evidenced that ZnO/NG offered excellent photocatalytic performance, regardless of UV or visible light irradiation. Under UV light, graphene as an electron transporter effectively promoted the separation of photogenerated carriers, while under visible light graphene was sensitized from the ground-state to the excited-state. The resulting electrons were injected into the conduction band of ZnO to transform wide bandgap ZnO into a photocatalyst driven by visible light. This work provided a green and simple method to prepare ZnO/NG nanohybrids with efficient and stable photocatalytic performance for water pollution remediation.

Nickel nanoparticles inside carbon nanostructures: atomistic simulation

Ni nanoparticle on a graphene substrate, inside the fullerene and carbon nanotube was studied by molecular dynamics simulation technique. Morse interatomic potential have been used for Ni-Ni and Ni-C interactions, and AIREBO potential has been used for C-C interaction. The pairwise Morse potential was chosen for the description of the Ni–C interaction because of its simplicity. It is shown that Morse potential can satisfactory reproduce the properties of graphene-nickel system. The effect of boundary conditions on the interaction of Ni nanoparticle and graphene sheet are investigated. It is shown, that if the edges of graphene plane are set to be free, coverage of Ni nanoparticle by graphene or just crumpling of graphene is observed depending on the size of nanoparticle. It is found, that Ni nanoparticle tend to attach to the carbon surface - graphene plane or the shell of fullerene and nanotube. Moreover, Ni nanoparticle induce the deformation of the surface of carbon polymorph. The obtained results are potentially important for understanding of the fabrication of metal-carbon composites and interaction between graphene and metal nanoparticles in such a system.

Normal spinel structure ZnFe2O4/g-C3N4 enhanced catalytic activity for photo-Fenton degradation of methylene blue

Heterogeneous photo-Fenton technology has been widely employed to degrade organic dyes in wasterwater. In the present study, a composite consisting of normal spinel structure ZnFe2O4 nanoparticle and two-dimensional sheet of g-C3N4 was facilely synthesized. Different characterization technologies, such as XRD, XPS and VSM, were employed to demonstrate the normal spinel structure ZnFe2O4 formation. The composite shows higher catalytic activity for degradation of methylene blue (MB) than mixed spinel structure ZnFe2O4/g-C3N4. Simultaneously, the composite exhibits excellent stability and reusability.

Comparison of LSPR-mediated enhanced fluorescence excited by S- and P-polarized light on a two-dimensionally assembled silver nanoparticle sheet

Localized surface plasmon resonance (LSPR) excited by an oblique incidence of S- and P-polarized light to a two-dimensionally assembled silver nanoparticle sheet was investigated via enhanced fluorescence under total internal reflection fluorescence (TIRF) microscopy. The finite-difference-time-domain simulation demonstrated that the S-polarized light induced a strong plasmon coupling at a nanogap between the particles, which eventually led to a highly confined, strong, and “flattened” electric field on the entire surface. In contrast, the LSPR field excited by P-polarized light was located on the individual particles, having a relatively long tail in the axial direction (low confinement). The LSPR-mediated fluorescence appeared stronger under P-polarized light than under S-polarized light in the experiments using cyanine dye solutions, while the opposite result was obtained for the fluorescence bead snapshot (diameter: 200 nm). Magnified images of the single beads taken by a super-resolution digital CMOS camera (65 nm/pixel) revealed improved lateral resolution when S-polarized light was used on both the silver nanoparticle sheet and glass under TIRF microscopy.

Durability improvements of two-dimensional metal nanoparticle sheets by molecular cross-linked structures between nanoparticles

The durability of two-dimensional metal nanoparticle sheets is a crucial factor for realizing next-generation optoelectronic devices based on plasmonics such as organic light-emitting diodes. Here, we report improvements in the durability of Ag nanoparticle sheets by forming alkanedithiol (DT16) cross-linked structures between the nanoparticles. The cross-linked structures in a sheet were fabricated by the self-assembly of DT16-capped Ag nanoparticles with 10% coverage (AgDT16). The durabilities for thermal, organic solvent, and oxidation reactions of AgDT16 sheets were found to be improved owing to the cross-linked structures by comparing Ag nanoparticle sheets without the cross-linked structures. The absorbance spectra revealed that the Ag nanoparticle sheets without the structure are markedly damaged by each durability test, whereas the AgDT16 sheets remain. The molecular cross-linked structures between nanoparticles in two-dimansional metal nanoparticle sheets were found to have the potential to play a key role in the realization of plasmonic optoelectronic devices including metal nanoparticles.

Effect of cell morphology on electrical properties and electromagnetic interference shielding of graphene-poly(methyl methacrylate) microcellular foams

Nowadays, polymer-based foams have gained much attention for absorption of electromagnetic wave due to their desirable properties such as wide absorption band, low reflection and also light weight. However, the impact of the foam morphology including shape, cell size and its structure as open and close cell, on the electromagnetic wave has been rarely investigated. In this study, the operational conditions for manufacturing various structured foams based on poly(methyl methacrylate)/graphene nanoparticle sheets have been optimized for investigating the effect of cellular structure on the characteristics of electromagnetic wave as well as electrical properties. Hence, a foaming system with great controllability and repeatability has been employed. It should be noted that this system is capable of stabilizing the cellular structure with millisecond accuracy during and after the pressure drop. The close cell structured foam showed a decrement in the electrical and electromagnetic properties with increasing the cell size and shifting from spherical to polygonal shape. Moreover, the results related to the prepared open cell structured foams with similar cell size and density to close cell ones, have demonstrated higher absorption characteristics for microcellular open cell foams while shielding was better in close cell counterparts.

Conforming nanoparticle sheets to surfaces with Gaussian curvature.

Nanoparticle monolayer sheets are ultrathin inorganic-organic hybrid materials that combine highly controllable optical and electrical properties with mechanical flexibility and remarkable strength. Like other thin sheets, their low bending rigidity allows them to easily roll into or conform to cylindrical geometries. Nanoparticle monolayers not only can bend, but also cope with strain through local particle rearrangement and plastic deformation. This means that, unlike thin sheets such as paper or graphene, nanoparticle sheets can much more easily conform to surfaces with complex topography characterized by non-zero Gaussian curvature, like spherical caps or saddles. Here, we investigate the limits of nanoparticle monolayers' ability to conform to substrates with Gaussian curvature by stamping nanoparticle sheets onto lattices of larger polystyrene spheres. Tuning the local Gaussian curvature by increasing the size of the substrate spheres, we find that the stamped sheet morphology evolves through three characteristic stages: from full substrate coverage, where the sheet extends over the interstices in the lattice, to coverage in the form of caps that conform tightly to the top portion of each sphere and fracture at larger polar angles, to caps that exhibit radial folds. Through analysis of the nanoparticle positions, obtained from scanning electron micrographs, we extract the local strain tensor and track the onset of strain-induced dislocations in the particle arrangement. By considering the interplay of energies for elastic and plastic deformations and adhesion, we construct arguments that capture the observed changes in sheet morphology as Gaussian curvature is tuned over two orders of magnitude.

Surfactant-assisted synthesis of metallic cadmium, cadmium hydroxide nanostructures and their electrochemical charge storage properties.

We report a simple, surfactant-assisted room temperature synthesis of metallic cadmium nanoparticle sheets and their subsequent hydrolysis to the formation of rice-shaped monoclinic cadmium hydroxide nanostructures. These new nanostructures have demonstrated 30-40 fold superior electrochemical charge storage capacity along with quantized double layer charging of metal nanoparticles as compared to the bulk cadmium.