Ferrofluids - Science topic

With their notable thermal characteristics, fluids incorporating nanoparticles have significant importance in industrial processes. Due to the higher proficiency of hybrid nanofluid, this study is organized to observe the flow phenomenon and thermal characteristics of kerosene-oil-based hybrid ferrofluid in relation to the modified versions of two...

Thermomagnetic convection is a controlling phenomenon for heat-transfer in ferrofluids. It depends upon the magnetic field gradients, variation in magnetic susceptibility, particle concentration and temperature gradients. This article presents the effect of these parameters on cooling of a current carrying micro-wire in ferrofluid with a focus on m...

The term Ferrofluids is used to refer to the coherent colloidal suspension of nanometer size ferromagnetic particles or their oxides in base fluids such as oil, water etc. Due to decrease in size to nanometric level, the property of ferromagnetism shifts towards super-magnetism. It creates an opportunity to modify the thermophysical parameters of m...

Magnetic permeability (μ), dielectric permittivity (ε) and electrical conductivity (σ) of the six elastomer samples obtained by mixing silicone rubber (RTV-530) with a kerosene-based ferrofluid in different volume fractions, φ: 1.31%, 2.59% and 3.84%, were determined using the complex impedance measurements, over the frequency range (500 Hz-2 MHz)....

Dynamically manipulating droplet motion on hydrophobic surfaces is crucial in various fields, including biomedical, sensing, actuation, and oil–water separation applications. Ferrofluid droplets can be manipulated and controlled using external magnetic forces. The creation of ferrofluids involves multiple procedures that can affect the functionalit...

The rheological effect of manganese zinc (Mn-Zn) ferrite ferrofluid was studied and the impact of temperature on the magnetoviscosity and viscoelastic system of manganese-zinc ferrite ferrofluid generated by co-precipitation process is investigated. At 25 ◦C, a ferrofluid structure that is both hard and elastic is produced. As the temperature rises...

At low and high temperatures in the presence and absence of magnetic fields, the effects of shear rate, angular frequency, and shear strain on the rheological characteristics of zinc ferrite ferrofluid is investigated. Chemical co-precipitation was used to create a zinc ferrite ferrofluid that was then coated with oleic acid to improve the stabilit...

Magnetic pore fabrics (MPFs) are a promising approach to explore the 3D pore space of rocks. There exist empirical relationships between the orientation, degree, and shape of MPF with pore space geometry and permeability anisotropy. Nevertheless, the precise nature of these relationships remains elusive. A common assumption in MPF studies is that f...

This research aims to investigate the agglomeration processes of magnetoresponsive functionalized nanocluster suspensions in a magnetic field, as well as how these structures impact the behaviour of these suspensions in biomedical applications. The synthesis, shape, colloidal stability, and magnetic characteristics of PEG-functionalized nanocluster...

This research delves into the intricacies of a two-dimensional, steady flow of a ferrofluid within a porous medium, where the thermal conductivity is subject to temperature variations. The study encompasses the influence of magnetic dipoles, radiation, Brownian motion, and thermophore-sis phenomena as they interact with a stretching sheet. A novel...

This paper documents the spreading characteristics and heat transfer of a single ferrofluid droplet impinging onto dry solid surfaces with and without a magnetic field. Three surfaces were investigated: a pure silicon substrate, a silicon substrate with a thin titanium film, and a superhydrophobic coating. Fluid dynamics and cooling results of a fe...

This research article presents a study on the potential use of oil-based ferrofluid for the efficient removal of microplastics from water. The targeted analyte, micro-polystyrene (micro-PS), was chosen along with palm oil as the carrier liquid. Fourier Transform Infrared (FTIR) analysis was conducted to identify the main peaks in the ferrofluid, in...

Pore space in siliciclastic rocks is one of the most important petrophysical properties in geothermal and hydrocarbon reservoir rock characterization. We used the anisotropy of magnetic susceptibility (AMS) of ferrofluid-impregnated Permo-Triassic sandstones of different Buntsandstein and Rotliegend facies as a proxy for pore space anisotropy and p...

Stretchable and highly conductive elastomers with intrinsically deformable liquid metal (LM) fillers exhibit promising potential in soft electronics, wearables, human-machine interfaces, and soft robotics. However, conventional LM-elastomer (LME) conductors require a high loading ratio of LM and the post-sintering to rupture LM particles to achieve...

The current study presents a novelty with focusing on the magnetic field effect on a sudden expansion tube with expansion ratio, total length, and pitch length of the dimpled fin is 2.5, 1500 mm , and 3.0, respectively. The magnetizable Fe 3 O 4 /H 2 O Ferrofluid with different nanoparticle volumetric concentrations ( φ = 1.0 % and 2.0 % ) were use...

A typical Tesla thermomagnetic engine employs a solid magnetic wheel to convert thermal energy into mechanical energy, while thermomagnetic convection in ferrofluid is still challenging to observe because it is a volume convection that occurs in an enclosed space. Using a water‐based ferrofluid, we demonstrate a liquid Tesla thermomagnetic engine a...

Sustainability is no longer just a marginal topic but a key challenge for modern space flight activities. Consequently, the student group experiment FARGO (Ferrofluid Application Research Goes Orbital) is dedicated to increasing the longevity of specific space components and, thus, reducing wear and tear and resource consumption while simultaneousl...

Theoretical models have crucial importance in the design of algorithms for feedback control of robotic micromanipulation platforms. More importantly, theoretical models provide an understanding of the limits of each manipulation approach along with the identification of the key parameters that influence motion performance. Here, we provide a mathem...

Liquid marbles, droplets entrapped in a solid particle shell at the air-liquid interface, can respond to stimuli such as alternating magnetic fields. In this study, we examined liquid marbles composed of the ferrofluid core covered by diverse particles, including thermo-responsive polymer microspheres. The temperature elevation induced by an altern...

A significant growth of research on digital microfluidics has been achieved over the past several decades, and the field is still attracting increasing attention for fulfilling relevant mechanisms and potential applications. Numerous studies have been devoted to actively manipulating droplets in a variety of fundamental and applicational scenarios....

Gradov O.V. (2023). Externally controlled autowave reaction-diffusion structures in soft matter media and labyrinth instability patterns of ferrofluids as dynamic grooves for open microfluidic / optofluidic chips with variable geometry on the lens-less holographic detector [Oral Presentation]. In: Proc. ELOS 2023 (in press).

Recently, an increasing number of electromagnetic devices have been using smart fluids. These include ferrofluids, electrorheological fluids, and magnetorheological (MR) fluids. In the paper, magnetorheological fluids are considered for use in a spherical actuator for haptic applications. An approach is presented to the design and optimization of s...

A series of ferrite nanoparticles were synthesized via ion doping and then were coated by surfactant and dispersed in perfluorinated polyether oil (PFPE-oil), and the various ferrite ferrofluids were obtained. The scanning electron microscope was used to characterize the morphology of particles and the dispersed state of ferrofluid, energy-dispersi...

Droplet‐based lab‐on‐a‐chip systems offer vast possibilities in the manipulation, guidance, tracking, and labeling of individual droplet‐based bioreactors. One of the targeted application scenarios is in drug discovery where millions of unique codes are required, which is out of reach for current technologies. Here, a concept for the realization of...

Correction for 'Extraction of diazinon, haloxyfop-R-methyl, hexaconazole, diniconazole, and triticonazole in cheese samples using a ferrofluid based liquid phase extraction method prior to gas chromatography' by Mahdi Rouhi et al., Anal. Methods, 2023, 15, 3043-3050, https://doi.org/10.1039/D3AY00160A.

Rheological measurements under an applied magnetic field were used to investigate the changes to the internal structure and stability of an aqueous ferrofluid. The ferrofluid was prepared by dispersing 1.8 wt.% of maghemite nanoparticles with a size of d = 14 ± 3 nm and a saturation magnetization MS = 68 emu/g in water using citric acid as the surf...

The heat transfer in 3D MHD flows using magnetic nanofluids (Ferrofluids) on bi-directionally exponentially stretched foils is currently under investigation. Ongoing research aims to solve the problem of heat transfer in three-dimensional Magnetohydrodynamic (MHD) flows of magnetic nanoliquid (ferromagnetic liquids) on exponentially expanding two-d...

Improving the performance of heat sinks is very important in the development of cooling systems. In this study, the use of a novel combination method [magnetic field impingement jet (MF-IJ)] to improve the convective heat transfer coefficient in a designed heat sink is numerically investigated. To model heat transfer, a steady three-dimensional com...

An environmental friendly ferrofluid incorporating hydrophobic deep eutectic solvents derived from fatty acids, specifically caprylic acid, pelargonic acid, capric acid, and lauric acid have been developed. The fundamental physiochemical properties of the synthesised deep eutectic solvents ferrofluid were determined using Fourier transform infrared...

A vortex-assisted dispersive liquid–liquid microextraction (VA-DLLME) procedure using hydrophobic deep eutectic solvent–based ferrofluid (HDES-FF) as an extractant was established. The developed sample preparation method coupled with high-performance liquid chromatography–diode array detector (HPLC–DAD) was applied to the pretreatment and determina...

Mechanical vibrations can be effectively converted into electrical energy using a liquid type of energy harvesting device comprised of a ferrofluid and a permanent magnet-inductor coil assembly. Compared to solid vibration energy harvesting devices, the liquid nature of the ferrofluid overcomes space conformity limitations which allow for the utili...

Molecular vibration signals were amplified by the gold strip gratings as a result of grating resonances and nearby electric field hotspots. Colloidal gold island films exhibit similar enhancement; however, the uneven geometrical characteristics of these films restrict the tunability of the vibrational enhancement. Infrared absorption is enhanced by...

Iron oxide nanoparticles possess magnetic characteristics that enable their control and manipulation using external magnetic fields, making them suitable for a wide range of biomedical engineering applications. Consequently, this study investigates the ferrohydrodynamic interaction of hybrid magnetic nanoparticles in an ethylene glycol plus water m...

Magnetohydrodynamic (MHD) natural convection of non-Newtonian ferrofluid and entropy generation in a square enclosure containing a wavy cylinder was investigated. The inner wavy cylinder was assumed to be heated and the outer square enclosure to be cold. The ferrofluid's rheology was presented by the power-law model, while density fluctuations owin...

We present results of a magneto optical rotation (MOR) of polarization of light by a suspension of Cu 0.8 Zn 0.2 Fe 2 O 4 nanoparticles in water. Conventional MOR in a dielectric medium arises due to magnetic field induced anisotropy which, in turn leads to a birefringence. On the other hand, magneto optic effects in colloidal supsensions of magnet...

The magnetic body force is critical for modelling of convection in ferrofluids. Despite a long history in the development of the theories for ferro-hydrodynamics, literature from the last five years shows that a universal consensus has not been reached concerning the formulation of this term for ferrofluids. We present an updated derivation of the...

Recently, several fluidlike, shape‐adaptable magnetic microrobots have been developed to overcome the drawbacks posed by the rigid structure of traditional magnetic microrobots. However, most of their control systems rely on permanent magnet‐based systems, which are unfeasible for large‐scale environments, such as in vivo applications. Herein, an e...

We used dc magnetization and ac susceptibility to investigate the magnetic relaxation of ferrofluids made of 8 nm average-diameter Fe3O4 nanoparticles dispersed in hexane. Samples of different concentrations (δ) spanning two orders of magnitude ranging from 0.66 to 0.005 mg (Fe3O4)/mL (hexane) were used to vary the interparticle interaction strengt...

Water contamination is created by industrial and agricultural development and is a primary source of water pollution. Iron oxides and magnetite are examples of IONPs with a high surface area and adsorption capacity that can easily bind to numerous molecules, allowing them to remove pollutants such as turbidity, metals, organic debris, and bacteria...

Introduction: In recent years, various nanoparticles (NPs) have been discovered and synthesized for the targeted therapy of cancer cells. Targeted delivery increases the local concentration of therapeutics and minimizes side effects. Therefore, NPs-mediated targeted drug delivery systems have become a promising approach for the treatment of various...

Vertical drop impacts of ferrofluids onto glass slides in a non-uniform magnetic field have been studied using high-speed photography. Outcomes have been classified based on the motion of the fluid-surface contact lines, and formation of peaks (Rosensweig instabilities) which affect the height of the spreading drop. The largest peaks are nucleated...

A new polyindolocarbazole based polymer viz; ICZP4 has been synthesized via Suzuki cross coupling reaction. Subsequently, it has been modified as a semiconducting magnetic polymer hybrid (ICZP4F) with the assistance of a magnetic ferrofluid for the removal of Cr (VI) ions from waste streams. The characterization of ICZP4 has been done through FTIR,...

FARGO is short for Ferrofluid Application Research Goes Orbital which is a project developed by the Small Satellite Student Society of the University of Stuttgart (KSat e.V.) supported by the Institute of Space Systems at the University of Stuttgart (IRS). Selected as a winner of the Überflieger 2 competition by the Space Agency within the German A...

Biofouling is a major problem in all natural and artificial settings where solid surfaces meet liquids in the presence of living microorganisms. Microbes attach to the surface and form a multidimensional slime that protects them from unfavorable environments. These structures, known as biofilms, are detrimental and very hard to remove. Here, we use...

The necessity to improve magnetic building blocks in magnetic nano-structured soft materials stems from a fascinating potential these materials have in bio-medical applications and nanofluidics. Along with practical reasons, the interplay of magnetic and steric interactions on one hand, and entropy, on the other, makes magnetic soft matter fundamen...

Magnetic microbubbles (MMBs) have great potential applications in drug delivery and target therapy because they can be controlled by magnetic fields. In this paper, dynamic equations are derived by Lagrangian formalism and the behavior of MMBs subject to a combination field of magnetic and ultrasound field in an incompressible infinite fluid is ana...

This paper presents an ultrasensitive fiber surface plasmon resonance (SPR) magnetic field sensor using an Au/TiO2 Schottky junction coated on a plastic-clad multimode fiber (PMF) and immersed in the magnetic fluid (MF). The MF acts as the magnetic-sensitive material, and the Au/TiO2 film with a high dielectric constant excites SPR with high sensit...

Abstract Magnetic manipulation of droplets has emerged as a promising strategy to achieve several complex tasks ranging from targeted drug delivery and micro‐robotics to controlled chemical synthesis. Hence, proper control in creating magnetically responsive droplets is indispensable for successful implementation. Here, an impact‐based encapsulatio...

Technological solutions and demonstration concepts on novel ferrofluidic systems replacing mechanical components, are presented in this paper. In addition to minimizing wear and tear, ferrofluidic components are less prone to cause vibrations, enabling operation of sensitive payloads like Earth observation equipment. Current research activities inc...

This paper is devoted to a theoretical study of the magnetic properties of an ensemble of singledomain interacting magnetic nanoparticles embedded in an immobile polymer matrix. This model is typical for the description of magnetically active polymer ferrocomposites widely used in industrial and biomedical applications. A ferrocomposite is assumed...

A ferrofluid droplet confined in a Hele-Shaw cell can be deformed into a stably spinning “gear,” using crossed magnetic fields. Previously, fully nonlinear simulation revealed that the spinning gear emerges as a stable traveling wave along the droplet's interface bifurcates from the trivial (equilibrium) shape. In this work, a center manifold reduc...

Spinal cord injury (SCI) results in massive neuronal death, axonal disruption, and cascading inflammatory response, which causes further damage to impaired neurons. The survived neurons with damaged function fail to form effective neuronal circuits. It is mainly caused by the neuroinflammatory microenvironment at injury sites and regenerated axons...

Magnetic fluids are excellent candidates for several important research fields including energy harvesting, biomedical applications, soft robotics and exploration. However, notwithstanding relevant advancements such as shape reconfigurability, that have been demonstrated, there is no evidence for their computing capability, including the emulation...

For many human body diseases, treatments in the early stages are more efficient and safer than those in the later stages; therefore, detecting the early symptoms of a disease is crucial. One of the most significant early indicators for diseases is bio-mechanical motion. This paper provides a unique way of monitoring bio-mechanical eye motion based...

Many artificial miniature robotic collectives have been developed by emulating collective biological behaviors to overcome the inherent limitations of inadequate individual capabilities. However, the basic building blocks of the reported collectives are mainly in the solid state, where the morphological boundaries of internal individuals are clear...

The timely detection and diagnosis of diseases and accurate monitoring of specific genetic conditions require rapid and accurate separation, sorting, and direction of target cell types toward a sensor device surface. In that regard, cellular manipulation, separation, and sorting are progressively finding application potential within various bioassa...

The vestibular system in the inner ear plays a central role in sensorimotor control by informing the brain about the orientation and acceleration of the head. However, most experiments in neurophysiology are performed using head-fixed configurations, depriving animals of vestibular inputs. To overcome this limitation, we decorated the utricular oto...

Check the published open access version at https://www.sciencedirect.com/science/article/pii/S0017931023005161

Four oil blobs (bright) are spinning in the EMG 700 water-based ferrofluid (dark) in a pore in a micromodel driven by a rotating magnetic field. It shows the immiscible fluid-ferrofluid two-phase flow in a pore under a rotating magnetic field. Ferrofluid is a potential flooding fluid for enhanced oil recovery and a potential tracer for reservoir ch...

This paper discusses a numerical study performed in analysing the performance regarding the magnetic effect on the mixed convection stagnation-point flow of hybrid ferrofluid, examining the influence of viscous dissipation, convective boundary condition as well as Joule heating across a nonlinearly moving surface. Additionally, the hybrid ferroflui...