Influence Of Nanoparticle Shape Research Articles

Effect of Ellipsoidal Particle Shape on Tribological Properties of Lubricants Containing Nanoparticles

Adding nanoparticles can significantly improve the tribological properties of lubricants. However, there is a lack of understanding regarding the influence of nanoparticle shape on lubrication performance. In this work, the influence of diamond nanoparticles (DNPs) on the tribological properties of lubricants is investigated through friction experiments. Additionally, the friction characteristics of lubricants regarding ellipsoidal particle shape are investigated using molecular dynamics (MD) simulations. The results show that DNPs can drastically lower the lubricant's friction coefficient μ from 0.21 to 0.117. The shearing process reveals that as the aspect ratio (α) of the nanoparticles approaches 1.0, the friction performance improves, and wear on the wall diminishes. At the same time, the shape of the nanoparticles tends to be spherical. When 0.85 ≤ α ≤ 1.0, rolling is ellipsoidal particles' main form of motion, and the friction force changes according to a periodic sinusoidal law. In the range of 0.80 ≤ α < 0.85, ellipsoidal particles primarily exhibit sliding as the dominant movement mode. As α decreases within this range, the friction force progressively increases. The friction coefficient μ calculated through MD simulation is 0.128, which is consistent with the experimental data.

Differential study on the thermal–physical properties of metal and its oxide nanoparticle-formed nanofluids: Molecular dynamics simulation investigation of argon-based nanofluids

Abstract The influence of nanoparticle shape, volume fraction, and temperature on the thermal properties of nanofluids plays a pivotal role in engineering applications. However, there remains a considerable lack of systematic research comprehensively considering these factors to study the similarities and differences in the thermal properties of nanofluids composed of metals and their oxides and to conduct in-depth analyses of their internal mechanisms and characteristics. In this study, molecular dynamics simulations were conducted, employing reversing perturbation non-equilibrium molecular dynamics and non-equilibrium molecular dynamics methods. The thermal conductivity and viscosity of Al–Ar and Al2O3–Ar nanofluids were thoroughly investigated under the various influencing factors. Results reveal that under identical conditions, the thermal conductivity of Al–Ar nanofluid surpasses that of Al2O3–Ar nanofluid, exemplified by values such as 0.1832 W/m K (Al–Ar, 1.5%, cylinder, 86 K) versus 0.17745 W/m K (Al2O3–Ar, 1.5%, cylinder, 86 K). Furthermore, the viscosity of Al–Ar nanofluid is lower than that of Al2O3–Ar nanofluid, demonstrated by values such as 0.0004882 Pa S (Al–Ar nanofluid, 86 K, 2.5%, platelets) compared to 0.008975 Pa S (Al2O3–Ar nanofluid, 86 K, 2.5%, platelets). Subsequently, this study analyzed the difference in thermal conductivity between the two nanofluids from the perspective of microscale interface heat conduction by comparing the phonon density of states curves of Al, Ar, and Al2O3 in the two nanofluids for overlap. Subsequently, through radial distribution function analysis, the viscosity difference between Al–Ar and Al2O3–Ar nanofluids is explained based on nanofluid–solid interface and microstructural considerations. This research addresses the comprehensive lack of comparative studies on the thermal properties of nanofluids formed by metals and their oxides. The internal mechanisms underlying the thermal property differences of nanofluids formed by metals and their oxides were revealed from a microscopic perspective, which holds significant implications for the engineering applications of nanofluids.

Evaluating the Deicing Performance of Copper Sulfide Nanoparticle-Infused Transparent Photothermal Coatings on Glazing: An Integrative Experimental and Simulation Study

This study presents an efficient approach to fabricating photothermal coatings using copper sulfide (CuS) nanoparticles for effective deicing on glass. The influence of nanoparticle shape on light absorption was economically evaluated using Finite Different Time Domain (FDTD) simulations, identifying CuS nanorods as the optimal choice in terms of light absorption and heat generation. Simulation results guided the fabrication of transparent photothermal coatings incorporating CuS nanorods and transparent acrylic resin paint. Deicing tests under 808 nm illumination demonstrated efficient active deicing potential of the developed coating covered with a 3mm-thick ice layer, raising the surface temperature from-20.0 °C to 42.5 °C within 400s. This combined simulation guidance and test validation approach introduces a cost-effective method for designing high-performance deicing coatings embedded with photothermal nanoparticles.

Influence of nanoparticle shapes in nanofluid film boiling on vertical cylinders: A numerical study

This research explores how nanoparticle shapes affect the thermal behavior of nanofluid film boiling along a vertical cylinder, utilizing a Continuous-Species-Transfer method embedded in a Computational Multi-Fluid Dynamics framework. By modeling the behavior of nanoparticles in both liquid and vapor phases, with considerations for Brownian motion and thermophoresis, a comprehensive 2D axisymmetric analysis is conducted. The analysis focuses on the effects of various Al2O3 nanoparticle shapes – spheres, bricks, blades, cylinders, and platelets – on boiling heat transfer performance. Results demonstrate that while nanoparticle shape has a minimal impact on deposition dynamics, it significantly affects kinematic viscosity, particularly for platelet-shaped nanoparticles. Blade-shaped nanoparticles stand out for their substantial enhancement of thermal transport, as demonstrated by pronounced temperature gradients and elevated thermal conductivity. Furthermore, these nanoparticles contribute to a notable improvement in the Nusselt Number, suggesting enhanced efficiency in boiling heat transfer. This improvement is particularly significant at higher nanoparticle concentrations, where the effects are more pronounced, though not strictly linear when compared to the effects at lower concentrations. Future work will explore different nanoparticle materials, boiling scenarios, and experimental validation.

Radiation and Nanoparticles Shape Effect on Aligned MHD Jeffrey Hybrid Nanofluids Flow and Heat Transfer over a Stretching Inclined Plate

The study through a stretching medium is a topic in the field of fluid dynamics and heat transfer. It involves investigating the behaviour of fluid flow and heat transfer phenomena in situations where a medium, such as a solid surface, is continuously stretched or deformed. Jeffrey fluid are found in the applications in various fields, including engineering, materials science, and biomedical engineering. Water was combined with copper (Cu) and aluminium oxide (Al2O3) is used in this study by considering the influence of nanoparticles shape which are spherical, brick, cylindrical, platelet and blade. The Keller Box method is used to solve numerically the Jeffrey hybrid nanofluid's governing nonlinear partial differential equations (PDEs) to nonlinear ordinary differential equations (ODEs) using similarity transformation. The results for both the velocity and temperature profiles of Jeffrey hybrid nanofluids (Deborah number, β) as well as the skin friction and Nusselt number are presented graphically and in tabulated form. The result shows that the momentum boundary layer thickness is decrease for any increment of the value alignment angle of the magnetic field parameter, the interaction of the magnetic field parameter, alignment angle of the incline plate, the mixed convection parameter, the radiation parameter, and the nanoparticles shape except the value of the volume fraction of the nanoparticles for the increasing value of Deborah number (β). The skin friction is increases as any increment value of an alignment angle of magnetic field, interaction of magnetic parameter, radiation parameter and volume fraction of nanoparticles increase, while the Nusselt number is decrease for the value of radiation parameter. It also observed that the factor of nanoparticles shape result is significant with the Jeffrey hybrid nanofluids which is the nanoparticles shape with the highest skin friction coefficient and Nusselt number is blades shape.

Does Particle Size in Nanofluid Synthesis Affect Their Performance as Heat Transfer Fluid in Flat Plate Collectors?—An Energy and Exergy Analysis

A flat-plate collector is one of the most common solar collector systems due to its comparatively lower cost and maintenance. However, the performance of this type of collector is low; thus, research studies in the past decades have focused on improving its efficiency through various plate configurations and efficient working fluids. This study recognizes the research gap regarding the influence of nanoparticle shapes and their effects on improving the heat transfer properties in flat-plate collectors. In this study, fly ash nanofluid at 0.5% (with a range of nanoparticle sizes) was used as a working fluid to investigate the performance of a flat-plate collector. This study analyzed the behavior of the collector system via a range of Reynolds numbers in its laminar regime, between 800 and 2000. The results measured in this study showed that the maximum energy efficiency measured was 73.8%, which was recorded for the fly ash nanofluid at a nanoparticle size of 11.5 nm. At a Reynolds number of 2000, the fly ash nanofluid with a nanoparticle size of 11.5 nm showed a top heat loss coefficient of 4.78 W/m2K, while the top heat loss coefficient of a nanoparticle size (NPS) of 114 nm was 5.17 W/m2K. This study provides a framework for the significance of the nanoparticle size in the synthesis of nanofluids in both mono and hybrid composites and application in solar collector systems.

INFLUENCE OF NANOPARTICLE SHAPES WITH VARIABLE PERMEABILITY ON NON-DARCY POROUS MEDIUM

INFLUENCE OF NANOPARTICLE SHAPES WITH VARIABLE PERMEABILITY ON NON-DARCY POROUS MEDIUM

Influence of nanoparticle shapes on natural convection flow with heat and mass transfer rates of nanofluids with fractional derivative

Nanofluids are gaining extensive attention due to their thermo‐physical properties in technological and industrial fields for controlling the effects of heat transfer. Classical nanofluid studies are generally confined to models described by partial differential equations of an integer order where the memory effect and hereditary properties of materials are neglected. In order to overcome these downsides, the present work focuses on studying nanofluids with fractional derivative formed by differential equations with Caputo time derivatives that provides memory effect on nanofluid characteristics. Also, investigation on natural convective flow, heat, and mass transfer of nanofluids formed by different base fluids with different shapes of copper nanoparticles past an infinite vertical plate with radiation effect is carried out. The governing fractional differential equations are solved by employing Laplace transform technique with suitable boundary conditions. The different base fluids—water (H2O), SA:sodium alginate (C6H9Na O7), and EG:ethylene glycol (C2H6O2) and different shapes of nanoparticles—blade, brick, platelet, and cylinder are considered for the study. The exact solutions are obtained for the temperature, concentration, and velocity distributions and the respective Nusselt number, Sherwood number, and skin‐friction coefficient. The influence of non‐dimensional parameters provides physical interpretations of temperature, concentration, and velocity fields, Nusselt number, Sherwood number, and skin friction in detail with the help of graphical representations. From the results, it is found that nanofluid with water‐based blade‐shaped nanoparticle exhibits more velocity and temperature distributions. Also, strengthen of fluid flow, temperature, and concentration of nanofluids are inversely correlate with fractional order derivatives.

Thermal, microrotation, electromagnetic field and nanoparticle shape effects on Cu-CuO/blood flow in microvascular vessels

A thermal analysis of Cu-CuO/ blood nanofluids flow in asymmetric microchannel propagating with wave velocity is presented in this study. For the blood, a micropolar fluid model is considered to investigate the microrotation effects of blood flow. Thermal radiation effects and the influence of nanoparticle shape, electric double layer thickness, and electromagnetic fields on the flow are studied. Three types of nanoparticles shapes namely cylinder, bricks and platelets are taken into account. Governing equations are solved under the approximations of long wavelength, low Reynolds number, and Debye-Hückel linearization. Numerical computations are performed for the axial pressure gradient, axial velocity, spin velocity and temperature distribution. The effects of various physical parameters on flow and thermal characteristics are computed and their physical interpretation is also discussed. The outcomes indicate that the axial velocity of Cu-CuO/blood nanoparticles strongly depends on applied electromagnetic field and microrotation. The model's finding will be applicable in designing the smart electromagnetic micro pumps for the hemodialysis and lungs-on-chip devices for the pumping of the blood.

The Influence of Nanoparticle Shape on Protein Corona Formation.

Nanoparticles have become an important utility in many areas of medical treatment such as targeted drug and treatment delivery as well as imaging and diagnostics. These advances require a complete understanding of nanoparticles' fate once placed in the body. Upon exposure to blood, proteins adsorb onto the nanoparticles surface and form a protein corona, which determines the particles' biological fate. This study reports on the protein corona formation from blood serum and plasma on spherical and rod-shaped nanoparticles. These two types of mesoporous silica nanoparticles have identical chemistry, porosity, surface potential, and size in the y-dimension, one being a sphere and the other a rod shape. The results show a significantly larger amount of protein attaching from both plasma and serum on the rod-like particles compared to the spheres. Interrogation of the protein corona by liquid chromatography-mass spectrometry reveals shape-dependent differences in the adsorption of immunoglobulins and albumin proteins from both plasma and serum. This study points to the need for taking nanoparticle shape into consideration because it can have a significant impact on the fate and therapeutic potential of nanoparticles when placed in the body.

UV Lithography-Assisted Fabrication of Low-Cost Copper Electrodes Modified with Gold Nanostructures for Improved Analyte Detection.

An in-house UV lithography setup has been optimized to fabricate low-cost disposable electrochemical sensing Cu electrodes using a copper clad board. In view of the high oxidation probability of copper, the low-cost electrodes were modified using different gold nanostructures and a conducing polymer PEDOT:PSS to attain maximal signal output and improved shelf-life. Zero-dimensional (0D) gold nanoparticles (∼40 nm) and three-dimensional (3D) gold nanoflowers (∼38 nm) mixed with PEDOT:PSS were used as signal-enhancing conductors for the ultrasensitive detection of our model contaminant, methylene blue dye (MB). The bare copper electrode was sensitive to MB, linearly within the range of 4–100 μM, with a limit of detection of 3.49 μM. While for gold nanoparticle-PEDOT:PSS-modified electrode, the sensitivity of the electrode was found to increase linearly in the range of 0.01–0.1 μM, and for gold nanoflowers-PEDOT:PSS, the sensitivity achieved was 0.01–0.1 μM with the LOD as 0.0022 μM. For a PEDOT:PSS-modified Cu electrode, used as a comparative to study the contributing role of gold nanostructures towards improved sensitivity, the linearity was found to be in the range of 0.1–1.9 μM with the LOD as 0.0228 μM. A 6 times improvement in signal sensitivity for the nanoflower-PEDOT:PSS electrode compared to the nanoparticle-PEDOT:PSS-modified electrode indicates the influence of nanoparticle shape on the electrode efficiency. 3D gold nanoflowers with a large surface area-to-volume ratio and a high catalytic activity prove to be a superior choice for electrode modification.

Convective heat transfer performance of hybrid nanofluid in a horizontal pipe considering nanoparticles shapes effect

In this paper, the problem of steady forced convection heat transfer and fluid flow characteristics of a hybrid nanofluid flowing through an isothermally heated horizontal tube considering various nanoparticle shapes has been investigated numerically. The three dimensionless cylindrical coordinate equations are discretized using the finite volume method and solved via a FORTRAN program. A numerical parametric investigation is carried out for a tube filled with regular water, (TiO2/water) nanofluid and (Ag–TiO2/water) hybrid nanofluid. Four different types of nanoparticle shapes are considered in this study, spherical, cylindrical, platelets and blades, with different volume fractions ranging from 0 to 8% using water as a base liquid. The influence of nanoparticle shape, nanoparticle concentration and Reynolds number on the local Nusselt number and the friction factor is essentially examined. The results showed that the friction factor of both nanofluid and hybrid nanofluid flow was increased as the nanoparticle volume fraction increased for all kinds of nanoparticle shapes, whereas it decreased as the Reynolds number increased. Nusselt number increased with increase in the nanoparticle concentration and Reynolds number. The highest heat transfer rate was acquired for the maximum nanoparticle volume concentration by using blade nanoparticle shape followed by platelet shape, cylindrical shape and lastly the sphere shape. It was found that the maximum values of the friction factor were registered for platelet-shape nanoparticles.

Collagen-ZnO Scaffolds for Wound Healing Applications: Role of Dendrimer Functionalization and Nanoparticle Morphology.

Functionalized nanoparticle cross-linked collagen scaffolds offer improved properties to biomaterials and regenerated tissues, as influence of nanoparticle shape on collagen scaffold has received little attention. The present study evaluates the role of ZnO nanoparticle shape (sphere, rod, hexagonal, needle, flower, star, circular disk, doughnut, and cube) on collagen self-assembly. The nanoparticle was prepared by using coprecipitation method and subsequently functionalized with triethoxysilane poly(amidoamine) dendrimer generation 1 (TES-PAMAM-G1 or G1) on the nanoparticle surface. The self-assembly process of collagen, facilitated by EDC-NHS cross-linking, led to stable ZnO-TES-PAMAM-G1-collagen scaffolds. Physicochemical properties and biocompatibility of scaffolds were analyzed to determine the thermal, mechanical and pore size transformation and cell viability, etc. and obtained results compared against collagen scaffolds with/without EDC-NHS cross-linking. In vivo wound healing activity of ZnO-TES-PAMAM-G1-collagen scaffolds was tested on Albino rats that were subjected to excisional wounds and results were compared with control and collagen scaffold. Our findings suggested that the functionalized nanostructure mediated collagen scaffolds exhibited higher thermal (91.2 ± 0.3 °C) and mechanical stability (130.23-305.45 ± 0.1-2.0 MPa) than collagen scaffold (77.36 ± 0.5 °C and 7.96 ± 0.8 MPa). The result of in vivo wound healing study indicated that spherical shape of ZnO-TES-PAMAM -G1 NPs cross-linked collagen scaffold showed enhanced re-epithelization and faster collagen deposition than other scaffolds probably owing to their higher surface area, which led to higher grafting density on the surface. This work provides a new approach for designing nanoparticle mediated collagen scaffold for wound healing application.

The influence of nanoparticle shape on bilateral exocytosis from Caco-2 cells

Nanoparticles are easily to be taken up by cells but hard to be transported across epithelia, which plays an important role in absorption and toxicity. This paper aims to elucidate the effect of nanoparticle shape on bilateral exocytosis of Caco-2 cells. The fluorescent resonance energy transfer (FRET) probes (DiO and DiI) were utilized to label nanospheres and nanorods for determining and tracking nanoparticles. The results showed that more nanorods were internalized into Caco-2 cells than nanospheres. But the apical exocytosis rate of nanospheres from Caco-2 cells was faster than that of nanorods significantly. In addition, only less than 2% of intact nanoparticles were transported across monolayers for both nanoparticles, but the exocytosis behaviors between them was absolutely different. Compared to nanospheres, nanorods preferred basolateral exocytosis to apical exocytosis. Therefore, the shape is a critical parameter in cellular uptake and transport, even intracellular fate, which should be primarily considered in design of oral nanoparticles.

Mechanistic investigation for the axisymmetric transport of nanocomposite molybdenum disulfide-silicon dioxide in ethylene glycol and sphericity assessment of nanoscale particles

The present paper provides a comparative analysis between nano and hybrid nanofluid axisymmetric flow towards a radially stretching porous surface along with heat transfer mechanism in the presence of magnetic force and internal heat source/sink. The effect of various shapes of nanoparticles is also taken into account. The physical flow problem is modeled and presented in cylindrical coordinates. Governing nonlinear equations are converted into a system of differential equations by using the similarity approach. Numerical results are computed by means of a well-established and stable numerical procedure. The main implication of this research is the influence of nanoparticle shapes, internal heating and applied magnetic field on fluid flow and heat transfer. Computational results are extracted out with the help of mathematics software MATLAB. One of the key findings of the present analysis is the fact that the maximum temperature is achieved for lamina-shaped SiO2 and MoS2-SiO2 nanoparticles and the lowest temperature is attained in the case of sphere-shaped nanoparticles.

Influence of nanoparticle shapes on cellular uptake of paclitaxel loaded nanoparticles in 2D and 3D cancer models

Enhanced cellular uptake and efficient penetration of nanocarriers inside tumors is paramount to successful anti-cancer therapy.

Monte Carlo Investigation of Magnetization in Small Ferromagnetic Heisenberg Nanoparticles

Using the classical Heisenberg model and Monte Carlo simulations in the canonical ensemble, the effect of form, finite-size, and surface roughness on magnetization is investigated for ferromagnetic nanoparticle with uniaxial anisotropy and different nanoparticle shapes. In this work, cubical and spherical nanoparticles are considered; we have considered a simple nanoparticle where each site is occupied by a classical Heisenberg spin. Our numerical results show that the nanoparticle size and surface roughness have an impact and a considerable influence on the magnetic properties of these nanoparticles. But the influence of nanoparticle shapes is less significant when comparing magnetic behavior for cubical and spherical forms of the particle in a smooth or rough surface.

First-principles calculations of the dissolution and coalescence properties of Pt nanoparticle ORR catalysts: The effect of nanoparticle shape

The degradation of Pt nanoparticles (NPs) in fuel cell cathodes leads to the loss of the precious metal catalyst. While the effect of NP size on Pt dissolution has been studied extensively, the influence of NP shape is largely unexplored. Because of the recent development of experimental methods to control the shape of metal NPs, rational guidelines/insights on the shape effects on NP stability are imperative. In this study, first-principles calculations based on density functional theory were conducted to determine the stability of 1–2 nm Pt NPs against Pt dissolution and coalescence with respect to NP shape. Toward dissolution, the stability of the Pt NPs increases in the following order: Hexagonal close-packed < icosahedral < cuboctahedral < truncated octahedral. This trend is attributed to the synergy of the oxygen adsorption strength and the local coordination of the Pt atoms. With respect to coalescence, the size of a NP is related to its propensity to coalesce or detach/migrate to form larger particles. The stability of the Pt NPs was found to increase in the following order: Hexagonal close-packed < truncated octahedral < cuboctahedral < icosahedral, and was correlated with the cohesive energies of the particles. By combining the characteristic stabilities of the shapes, new “metal-interfaced” Pt-based coreshell architectures were proposed that should be more stable than pure Pt nanoparticles with respect to both dissolution and coalescence.

Sphere to rod transitions in self assembled systems probed using direct force measurement.

The influence of nanoparticle shape, in particular the sphere to rod transition, on surface forces and consequently the properties of colloidal fluids is an interesting but not well investigated phenomenon. Here, the surface force behaviour of concentrated surfactant solutions containing cetyltrimethylammonium bromide and sodium salicylate with micelle shapes varying from slightly prolate to high aspect ratio rods was measured. Atomic force microscopy (AFM) with both rigid particle and soft droplet probes was used with comparisons and analysis made using the Chan-Dagastine-White model. It is observed that small changes to the micelle shape result in no discernable differences to the surface force behaviour, however, once the micelles are elongated significantly, the long range forces adjust in nature from oscillatory to that of a single attractive force well. This highlights the importance that nanocolloid shape has on the behaviour and properties of emulsions and other colloidal fluids, specifically for emulsion flocculation and handling in systems of rod and worm like micelles.

Influence of nanoparticle shape on charge transport and recombination in polymer/nanocrystal solar cells.

A key consideration for the efficient operation of hybrid solar cells based upon conjugated polymers and inorganic semiconductor nanocrystals is charge transport in the nanocrystal phase. Here we report the results of a study into the charge transport kinetics of polymer/nanocrystal solar cells based on blends poly(3-hexylthiophene) (P3HT) with either CdSe nano-dots or CdSe nano-tetrapods. Transient photocurrent measurements reveal significant differences in the charge transport kinetics of nano-dot and nano-tetrapod hybrid cells, with the charge collection of the P3HT/CdSe nano-dot device severely limited by charge trapping. In comparison the nano-tetrapod cell exhibits significantly reduced charge trapping compared to the nano-dot cell accounting for the improved fill-factor and overall device efficiency. Transient photovoltage measurements have also been employed that demonstrate slower recombination rates in the P3HT/CdSe tetrapod device compared to the P3HT/CdSe dot device. These observations directly identify nanoparticle shape as a critical factor influencing the charge transport and hence recombination in this benchmark hybrid system, confirming the hypothesis that the use of tetrapods improves device performance through an improvement in electron transport in the nanocrystal phase.