Juan de VicenteUniversity of Granada | UGR · Department of Applied Physics
Juan de Vicente
Professor
Magnetic soft matter under unsteady triaxial magnetic fields
About
164
Publications
37,120
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
6,260
Citations
Publications
Publications (164)
We design, fabricate, and test a double-gap bicone magnetorheological (MR) device to measure steady shear rheological properties of MR fluids under saturating magnetic fields (i.e., large enough to saturate the MR fluids). The device is optimized using finite element method and computational fluid dynamics simulations so that homogeneous, saturatin...
The field of stimuli-responsive supramolecular biomaterials has rapidly advanced in recent years, with potential applications in diverse areas such as cancer theranostics, tissue engineering, and catalysis. However, designing molecular materials that exhibit predetermined hierarchical self-assembly to control the size, morphology, surface chemistry...
Magnetic field generators with the ability to create well-controlled dynamic fields in arbitrary directions are an essential tool to investigate magnetic soft matter and to drive (sub)micrometer structures to targeted locations. In this article we present the design and performance of a triaxial generator based on three fractal capacitor banks that...
In order to generate homogeneous magnetophoretic forces, current magnetic tweezer devices operate placing electromagnetic inductors far enough from the sample. Consequently, high-power supplies are needed to reach sufficiently large forces. We demonstrate that both magnetophoretic force magnitude and homogeneity can be increased at will in this kin...
Magnetically responsive soft matter is a colloidal model system where interparticle interactions can be tuned through external magnetic fields. Covering the most recent literature in the field, with special emphasis on the physical mechanisms behind their rheological behaviour, this book aims to demonstrate the controllability of soft matter throug...
Magnetorheological fluids structured under precession fields are thoroughly investigated. Having complete dynamic triaxial magnetic field control, we are able to study both the structural and magnetorheological response via videomicroscopy and rheometry integration for a wide range of magnetic field configurations, once previously limited to tradit...
Magnetorheological elastomers are a class of stimuli-responsive materials of which the damping and stiffness can be reversibly tailored by applying magnetic fields. However, concerns such as fatigue damage, poor magnetorheological (MR) efficiencies with low loadings of magnetic particles or highly crosslinked elastomers, and lack of reprocessabilit...
Shear thinning fluids represent a class of non-Newtonian media characterized by a decrease of the apparent viscosity when increasing the shear rate. Here we experimentally demonstrate a deterministic ratchet effect in such media that enables directed transport of microscopic particles under a square-wave magnetic force. The applied modulation is de...
The rheology of concentrated suspensions of particles is complex and typically exhibits a shear-thickening behaviour in the case of repulsive interactions. Despite the recent interest arisen, the causes of the shear-thickening remain unclear. Frictional contacts have been able to explain the discontinuous shear thickening in simulations. However, t...
Probiotic cellulose (PC), a living material (LM) consisting of probiotics integrated into bacterial cellulose, is the first example where life (probiotic proliferation) is the input to tune the viscoelasticity of the biomaterial. The gradual proliferation of probiotics within the matrix acts as a key modulator of the cellulose viscoelasticity, prov...
The postyield rheological regime is investigated in sheared magnetic field-responsive composites (i.e. carbonyl iron based magnetorheological fluids). When subjected to uniaxial DC fields, high-speed videomicroscopy techniques and dedicated image analysis tools demonstrate that dispersed magnetic microparticles self-assemble to form concentric laye...
We demonstrate a new route to enhance magnetorheology using precession-like magnetic fields. This field configuration is generated by the superposition of a 2D rotational field applied orthogonal to a uniaxial DC field. Maintaining a columnar linear chain structure when applying a precession field was determined to be integral in increasing the ave...
The physico-chemical and tribo-rheological characteristics of calcium-induced skim milk gels obtained by heating of milk dispersions prepared with different concentrations of skim milk powder (10, 20 and 30% w/w) and calcium chloride (30, 60 and 90 mmol kg⁻¹) were studied. The effect of pH on the gelation and on the final gel structure was also ana...
A new formulation is proposed to lubricate tribopairs in extreme conditions where the amount of lubricant is small and the lubricating region highly confined. It is composed of non-magnetic solid lubricants dispersed in an oil-based ferrofluid. When this inverse ferrofluid (IFF) is magnetically activated, the lubricant particles are subjected to ma...
A new type of magnetorheological (MR) material is reported that brings together conventional MR composites (MRCs) and biomaterials. Living MRCs based on carbonyl iron microparticles (CIPs) as magnetoactive filler, sodium alginate as elastomer and cells as biological components were prepared and characterized. The effect of CIPs concentration in iso...
We propose three different techniques to synthesize anisotropic magnetic supraparticles for their incorporation in the formulation of magnetorheological fluids with novel potential applications. The techniques include microtransfer molding, electrodeposition and microfluidic flow-focusing devices. Although the yield of these methods is not large, w...
The use of decellularized extracellular matrix (dECM) as a biomaterial has been an important step forward for the development of functional tissue constructs. In addition to tissues and organs, cell cultures are gaining a lot of attention as an alternative source of dECM. In this work, a novel biomimetic hydrogel is developed based on dECM obtained...
Hydrogels with self-healing properties constitute one of the most versatile three-dimensional (3D) materials for application in biomedicine due to the possibility of modulating their characteristics and incorporating specific elements such as magnetic particles (MPs). Herein, we describe a simple approach on the fabrication of self-healing magnetic...
The most pressing need in cartilage tissue engineering (CTE) is the creation of a biomaterial capable to tailor the complex extracellular matrix of the tissue. Despite the standardized used of polycaprolactone (PCL) for osteochondral scaffolds, the pronounced stiffness mismatch between PCL scaffold and the tissue it replaces remarks the biomechanic...
Traditionally, the rheological properties of magnetorheological (MR) fluids are investigated under uniaxial steady (DC) fields. These basic fields promote the aggregation of magnetically attractive particles into chain-like structures aligned in the field driven direction. In this manuscript we show how triaxial unsteady fields can generate a varie...
Tissue engineering (TE) seeks to fabricate implants that mimic the mechanical strength, structure, and composition of native tissues. Cartilage TE requires the development of functional personalized implants with cartilage‐like mechanical properties capable of sustaining high load‐bearing environments to integrate into the surrounding tissue of the...
Laboratory experiments with intact sediment cores from a hypertrophic very windy exposed shallow lake were conducted to assess the combined effect of anoxia and sediment resuspension on phosphorus (P) dynamics after adding different P adsorbents (CFH-12® and Phoslock®). In this study we hypothesize that the addition of geoengineering materials will...
Magnetic Soft Matter is a rapidly evolving discipline with fundamental and practical interest. This is due to the fact that its physical properties can be easily controlled through external magnetic fields. In this review paper, we revisit the most recent progress in the field (since 2010) emphasizing the rheological properties of these fascinating...
Bioprinting is a promising tool to fabricate well-organized cell-laden constructs for repair and regeneration of articular cartilage. The selection of a suitable bioink, in terms of composition and mechanical properties, is crucial for the development of viable cartilage substitutes. In this study, we focused on the use of one of the main cartilage...
The underlying physics behind magnetorheological fluids is described under the presence of uniaxial DC fields and steady simple shear. A universal master curve exists in terms of two dimensionless numbers (the particle volume fraction and the Mason number). Especial emphasis is given to the particle concentration dependence.
The oleogelation process has become in a great interest area for the food sector. The aim of this study was to understand the effect of cooling temperature profiles (CTP) applied during oleogelation on microstructure and some macroscopic properties of monoglycerides (MG) oleogels. To this purpose, oleogels from MG and high oleic sunflower oil were...
Magnetic colloids were formulated by dispersion of magnetic oxide spheres in water. Their rheological behavior was investigated for a wide range of particle diameters covering in detail the magnetic single-multidomain transition and therefore spanning the gap between ferrofluids and conventional magnetorheological fluids. The magnetoviscous effect...
Understanding magnetorheology in saturating fields is crucial for success in high torque applications. In this paper we use numerical computations, analytical developments, and experimental data (using a double-gap magnetocell) to study the saturation behavior of model magnetorheological fluids for different particle loadings. Numerical calculation...
The yielding behavior of magnetorheological fluids is revisited through the use of finite element method calculations on model structures and carefully conducted experiments in a magnetorheometer. Model structures investigated in this work are monoclinic lattices with simple and body centered bases. From the simulation point of view we emphasize th...
Comprehension of the tribological behavior of magnetorheological fluids is crucial for many applications, in particular for those related with high quality surface finishing. In this contribution, we describe a thorough experimental investigation on the tribological properties of magnetorheological (MR) fluids in poly(methyl methacrylate) (PMMA) po...
We simulate the thin-film and frictional properties of shear-thinning and shear-thickening fluids in the isoviscous elastohydrodynamic (I-EHL) regime in point contacts. A double-Newtonian Carreau-Yasuda viscosity model is employed to incorporate the shear rate dependence of the viscosity. Regression formulas for the film thickness and friction coef...
Currently, we are facing increasing demand to develop efficient systems for the detection and treatment of diseases that can realistically improve distinct aspects of healthcare in our society. Sensitive nanomaterials that respond to environmental stimuli can play an important role in this task. In this manuscript, we review the clinical trials car...
Undoubtedly, the yield stress is the most relevant rheological property of a magnetorheological (MR) fluid. However, available analytical and simulation methodologies to compute the magnetostatic interparticle interactions that govern the yield stress, fail at large particle concentrations and large strain levels. In this communication we propose a...
Progress in nanotechnology has enabled us to open many new fronts in biomedical research by exploiting the peculiar properties of materials at the nanoscale. The thermal sensitivity of certain materials is a highly valuable property because it can be exploited in many promising applications, such as thermo-sensitive drug or gene delivery systems, t...
A double-gap magnetorheological (MR) cell is designed, constructed, and validated using finite element method magnetostatics simulations, computational fluid dynamics calculations, and experimental data with Newtonian fluids and conventional MR fluids for a range of particle concentrations and external magnetic field strengths. This new cell is a g...
In this work the fat mimicking mechanism of microparticulated whey proteins (MWP) in milk-based systems was studied using rheological and tribological techniques. Flow curves and friction measurements in a soft contact of skim milk-MPW dispersions (SM-MPW) and skim milk-dairy fat emulsions (SM-DF) at different concentrations (3, 6, 9, 12, 15, 18 an...
In this manuscript we investigate the shear rheology, sedimentation stability and redispersibility characteristics of bimodal MR fluids with a Large-to-Small size ratio σ_L/σ_S≈100 where the small-size population of particles is in the single- multidomain limit (σ_S≈100 nm) to promote the formation of core-shell supraparticles (i.e. large particles...
We demonstrate a new route to enhance the magnetorheological effect using bimodal suspensions in the single-multidomain limit. Experimental results are satisfactorily compared to 3D finite element method simulations. The physical reason behind this enhancement is the coating of the larger particles by the smaller ones due to the remnant magnetizati...
A new kind of magnetorheological fluid is proposed that exhibits both enhanced magnetorheological effect and kinetic stability against sedimentation. It includes the presence of small amounts of an emulsified aqueous ferrofluid as a third phase in a conventional oil-based magnetorheological fluid prepared by the dispersion of carbonyl iron micropar...
Phosphorus (P) removal from lake/drainage waters by novel adsorbents may be affected by competitive substances naturally present in the aqueous media. Up to date, the effect of interfering substances has been studied basically on simple matrices (single-factor effects) or by applying basic statistical approaches when using natural lake water. In th...
Drilling fluids used in the oil industry are complex mixtures of a base component and different additives. Each additive provides a specific property, which helps to control the performance of the fluid and permits an efficient drilling operation. The lubricity function of a drilling fluid is extremely important due to the existence of large fricti...
The goal of this study is to investigate the field-driven structuration of model magnetorheological (MR) fluids in narrow gaps (below 1 mm) for high shear applications. With this in mind, we study the influence of confinement in the aggregation kinetics of dilute carbonyl iron suspensions under strong fields (≈ 10⁶) in rectangular microchannels usi...
A particle-level simulation methodology is proposed to study the squeeze flow behavior of model magnetorheological fluids. The simulation algorithm takes into account Brownian motion and local field corrections to magnetic interactions of the particles. Simulation results obtained from using different initial configurations, including one single-pa...
We demonstrate the influence of experimental conditions (carrier fluid viscosity and particle–wall interactions—friction) on the quasi-2D deterministic aggregation kinetics of carbonyl iron magnetic suspensions in rectangular microchannels. On the one hand, the carrier fluid viscosity determines the time scale for aggregation. On the other hand, fr...
The equilibrium structure and dynamics of magnetorheological (MR) fluids are studied in this work by simulations, where particles are modeled as dipoles with a quasihard spherical core. Upon increasing the interaction strength, controlled experimentally by the magnetic field, elongated clusters grow and, for intense fields, thick columns form, alig...
We demonstrate that inverse ferrofluids behave as model magnetorheological fluids. A universal master curve is proposed, using a reduced Mason number, under the frame of a structural viscosity model where the magnetic field strength dependence is solely contained in the Mason number and the particle concentration is solely contained in the critical...
We investigate the (irreversible) two-dimensional aggregation kinetics of dilute non-Brownian magnetic suspensions in rectangular microchannels using video-microscopy, image analysis and particle-level dynamics simulations. Special emphasis is given to carbonyl iron suspensions that are of interest in the formulation of magnetorheological fluids. T...
We propose a novel magnetic adsorbent for optimal Phosphorus (P) removal from the upper sediment
layers. For this aim, magnetic chitosan microparticles were prepared using a reverse-phase suspension
cross-linking technique. The resulting particles and suspensions were characterized using scanning
electron microscopy, X-ray powder diffraction, Fouri...
This study used microcosms to evaluate the effects of adding iron (Fe) magnetic microparticles (MPs) on water quality, focusing on P concentrations in the water column and sediment. Two treatments were considered for a constant 85:1 MP:PMobile molar ratio: T-W, applying MPs on the surface water layer; and T-S, applying MPs on the sediment. MP addit...
Faceted particles have been used to prepare dilute magnetorheological (MR)
fluids with enhanced aggregate strength. The measured storage modulus of these suspensions is significantly larger than that of the MR fluids prepared with spherical particles, and comparable to that of the rod-based fluids, whereas no sign of formation of a percolated syst...
We propose a micromechanical model for the behavior of dilute magnetorheological fluids under unidirectional slow-compression, constant-volume squeeze flow mode. In the linear magnetization regime, the model predicts a power law scaling of the normal stress with the particle volume fraction and magnetic field strength squared at low fields. The pre...
An extensive experimental and simulation study is carried out in conventional magnetorheological fluids formulated by dispersion of mixtures of carbonyl iron particles having different sizes in Newtonian carriers. Apparent yield stress data are reported for a wide range of polydispersity indexes (PDI) from PDI = 1.63 to PDI = 3.31, which for a log-...
The mean magnetization (MM) approximation is undoubtedly the most widely used approximation in magnetorheology both from theoretical and simulation perspectives. According to this, spherical magnetizable particles under field can be replaced by effective dipole moments m placed at their center with strength m = Vp〈Mp〉. Here Vp and 〈Mp〉 are the volu...
We report a finite element method study on the effect of surface roughness on the field-induced magnetization of micrometric iron particles and on the interparticle magnetostatic forces between them. Calculations were carried out for two-dimensional geometries in which particles were modelled as discs. Roughness was introduced as semicircular protr...
We investigate model magnetorheological (MR) fluids (inverse ferrofluids) under both steady and dynamic oscillatory shear. Analytical theories, particle-level simulations, and magnetorheometry are used in an attempt to obtain universal master curves. Steady shear flow data can be collapsed when plotted as a function of a dimensionless Mason number....
This work reports an investigation into the effect of 1-octanol concentration in the formulation of concentrated polyalphaolefin-based magnetorheological fluids. Special emphasis is paid to the understanding of their kinetic stability and redispersibility characteristics in the 'off-state' (absence of magnetic field). Techniques employed involve li...
This work proposes the use of quartz crystal microbalances (QCMs) as a method to analyze and characterize magnetorheological (MR) fluids. QCM devices are sensitive to changes in mass, surface interactions, and viscoelastic properties of the medium contacting its surface. These features make the QCM suitable to study MR fluids and their response to...
We investigate the influence of the aspect ratio of the dispersed particles in magnetorheology. Two systems are studied: conventional magnetorheological fluids prepared by dispersion of nickel nanowires, and inverse ferrofluids prepared by dispersion of glass fibers in a ferrofluid. In both cases the apparent yield stress is found to increase with...
In the last decades, magnetic particles (MPs) as adsorbents have gained special attention due to their high adsorption capacity and the possibility of recovering them by applying a magnetic separation gradient. For the first time MPs have been tested as P adsorbents in a microcosm experiment in a context of lake restoration. MPs were added to sedim...
The yielding behaviour of magnetorheological fluids has been investigated by videomicroscopy, ultrasonic and rheometry techniques simultaneously. Particularly, the effect of different factors such as, the magnetic field strength, particle size, surface chemistry of the particles, particle concentration and carrier fluid viscosity has been studied....
In this work, a range of ionic liquids (IL), all based on 1-alkyl-3-methylimidazolium, [EMIM]+, and [BMIM]+ cations, with different anions, [NTf2]−, [CF3SO3]−, [SCN]−, [BF4]−, [PF6]−, and [CH3COO]−, were used as carrier fluids to prepare magnetorheological (MR) fluids with 30 vol % carbonyl iron powder (CIP), grade EW (BASF SE), without additives....
The specific adsorption of phosphate (P) on strongly magnetisable carbonyl iron (Fe) particles and their subsequent removal by in-flow High Gradient Magnetic Separation (HGMS) is considered a promising tool for restoring eutrophied waters. A previous study showed the existence of chemical interferences in natural waters without considering the infl...
A simulation method is proposed to explore the effect of particle size polydispersity in magnetorheology including Brownian motion. The method aims to extend the classical particle-level simulation methodology developed by Klingenberg et al. [J. Chem. Phys. 91, 7888–7895 (1989)] for the case of polydisperse magnetorheological (MR) fluids. The simul...
A range of ionic liquids (ILs)-based magnetorheological (MR) fluids are formulated and their tribological properties investigated in steel–steel, polyoxymethylene–polyoxymethylene POM–POM and polydimethylsiloxane–polydimethylsiloxane PDMS–PDMS point contacts. The effect of particles in dispersion is investigated by measuring neat ILs in the same tr...
This work presents a technique and develops an apparatus that allows the application of homogeneous external magnetic fields (parallel or perpendicular to the deformation axis) to a fluid sample undergoing extensional flow kinematics while measuring the filament thinning using the commercial version of the capillary breakup extensional rheometer (H...
We report a study on the effect of particle roughness on the strength of the field-induced structures of magnetorheological (MR) fluids in the quasi-static regime. We prepared one set of MR fluids with carbonyl iron particles and another set with magnetite particles, and in both sets we had particles with different degrees of surface roughness. Sma...
A direct comparative study on the creep-recovery behavior of conventional magnetorheological (MR) fluids is carried out using magnetorheometry and particle-level simulations. Two particle concentrations are investigated ( ϕ = 0.05 and 0.30 ) at two different magnetic field strengths (53 and 173 kA·m−1) in order to match the yield stresses developed...
This paper demonstrates a new route to control friction in the isoviscous elastic lubrication regime between compliant point contacts. For this aim, the superposition of non-homogeneous magnetic fields in ferrofluid lubricated contacts is proposed. Under appropriate conditions, a friction reduction is observed by simply displacing the magnetic fiel...
We report a systematic experimental investigation on the use of nanofibers to enhance the magnetorheological (MR) effect in conventional (microsphere-based) MR fluids formulated in polyalphaolefin oil/1-octanol. Two kinds of nanofibers are employed that have very similar morphology but very different magnetic properties. On the one hand we use non-...
The lubricating properties of two different magnetic colloids were evaluated both in the absence and presence of external magnetic fields under sliding friction using the ball-on-three-plates geometry and stainless steel–steel point contacts. Specifically, the magnetic colloids studied were commercially-available ferrofluids (i.e., low concentratio...
We use particle level dynamic simulations, ultrasonic characterization, and rheomicroscopy to investigate the yielding behavior of magnetorheological (MR) fluids under oscillatory shear in both dilute and concentrated regimes. Dilute suspensions exhibit a single peak in the elastic stress that is associated to the breaking of the field-induced stru...
An extensive experimental work is reported that aims to assess the efficiency in manganese (Mn) removal from aqueous solution by carbonyl iron microparticles using magnetic separation techniques. A set of batch experiments are performed to explore the effect of pH, adsorbent concentration, surface coating and contact time for achieving the highest...
Unlabelled:
>
Aims:
N-oleoylethanolamine (OEA) is a lipid mediator that acts as a satiety factor. The main limiting factor for its administration is its poor water solubility. We designed and characterized new nanoemulsions as delivery system for hydrophobic compounds such as OEA.
Materials & methods:
The nanoemulsion components and preparatio...