Magnetorheology of Core–Shell Structured Carbonyl Iron/Polystyrene Foam Microparticles Suspension with Enhanced Stability

Macroscopic Room-Temperature Magnetoelectricity in Piezoelectric (Core)-Ferrimagnetic (Shell) Nanocomposites

The magnetoelectric (ME) effect, which involves the interaction of magnetic and electric fields within a material, has a significant potential for various applications. Our study addresses the limitations of conventional magnetostriction-based ME materials by demonstrating an alternative approach that achieves substantial ME effects in core-shell-type nanocomposites at room temperature. By synthesizing ferrimagnetic Fe3O4 nanoparticles onto piezoelectric poly(vinylidene fluoride) (PVDF) particles, we identified a distinct ME mechanism. In magnetorheological (MR) fluids, the magnetic-field-induced aggregation of Fe3O4 nanoparticles, combined with the piezoelectricity of PVDF, leads to a pronounced ME effect, significantly enhancing the performance and stability of MR fluids. This research highlights a crucial observation of distinct ME effects, which could suggest potential pathways for advancements in practical applications including microfluidics, vibration dampers, tactile technologies, and biomedical and bioengineering fields.

Topology optimization of adaptive sandwich plates with magnetorheological core layer for improved vibration attenuation

In this study the optimum topology distribution of the magnetorheological elastomer (MRE) layer in an adaptive sandwich plate is investigated. The adaptive sandwich plate consists of an MR elastomer layer embedded between two thin elastic plates. A finite element model has been first formulated to derive the governing equations of motion. A design optimization methodology incorporating the developed finite element model has been subsequently developed to identify the optimum topology treatment of the MR layer to enhance the vibration control in wide-band frequency range. For this purpose, the dynamic compliance and density of each element are defined as the objective function and design variables in the optimization problem, respectively. The method of the solid isotropic material with penalization (SIMP), is extended for material properties interpolation leading to a new MRE-based penalization (MREP) model. Method of moving asymptotes (MMA) has been subsequently utilized to solve the optimization problem. The developed finite element model and design optimization method are first validated using benchmark problems. The proposed design optimization methodology is then effectively utilized to investigate the optimal topologies of the magnetorheological elastomer (MRE) core layer in MRE-based sandwich plates under various boundary and loading conditions. Results show the effectiveness of the proposed design optimization methodology for topology optimization of MRE-based sandwich panels to mitigate the vibration in wide range of frequencies.

Carbonyl Iron Particles' Enhanced Coating Effect Improves Magnetorheological Fluid's Dispersion Stability

The coating effect of 1,2-bis(triethoxysilyl)ethane (BTES) on carbonyl iron particles (CIPs) was enhanced by etching with hydrochloric acid (HCl) of various concentrations, and magnetorheological fluids (MRFs) with significantly improved dispersion stability were obtained. The microstructures, coating effect, and magnetism of CIPs were examined using scanning electron microscopy (SEM), automatic surface and porosity analysis (BTE), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and a vibrating sample magnetometer (VSM), respectively. Furthermore, the rheological properties and dispersion stability of the MRFs were assessed by a rotating rheometer and a Turbiscan Tower. The results show that as the HCl concentration increased, nanopores appeared on CIPs and then disappeared, and the specific surface area of the particles increased and then decreased. When the concentration of HCl was 0.50 mol/L, the number of nanopores and the specific surface area of particles changed sharply. Not only that, the coated mass of BTES increased greatly and the saturation magnetization of particles decreased sharply. As the coated mass increased, without a magnetic field, the viscosity and shear stress of the MRFs increased, especially when the coated mass was more than 2.45 wt.%; while under a magnetic field, the viscosity and shear stress decreased, and the sedimentation rate of the MRFs decreased from 0.13 to 0.01 mm/h. By controlling the concentration of HCl for etching, the coating effect of CIPs was greatly enhanced, and thus an MRF with superior shear stress and excellent dispersion stability was obtained, which is significant in basic research and MRF-related applications.

Effect of the surface coating of carbonyl iron particles on the dispersion stability of magnetorheological fluid

The dispersion stability of carbonyl iron particle (CIP)-based magnetorheological fluid (MRF) is improved by CIP, which particle is etched with hydrochloric acid (HCl) to form porous structure with many hydroxyl groups and subsequently coated with silane coupling agents that have varying chain lengths. The microstructures, coating effect and magnetism of the CIPs were examined using the Scanning Electron Microscopy, Automatic Surface and Porosity Analyzer (BET), Fourier-Transform Infrared Spectroscopy, Thermogravimetric Analysis and Vibrating Sample Magnetometer. Furthermore, the rheological properties and dispersion stability of the MRFs were assessed using a Rotating Rheometer and Turbiscan-lab. The results revealed that the nanoporous structure appeared on the CIPs and the specific surface area increased remarkably after being etched by hydrochloric acid. Additionally, as the chain length of the silane coupling agent increases, the coated mass on the particles increases, the the density and the saturation magnetization of particles decreased, and the coated particles with different shell thicknesses were obtained; without a magnetic field, the viscosity of MRF prepared by coated particles increase slightly, due to the enhancement of special three-dimensional network structure; under a magnetic field, the viscosity of the MRF decreased distinctly; the sedimentation rate of MRF decreased from 58 to 3.5% after 100 days of sedimentation, and the migration distances of the MRFs were 22.4, 3.7, 2.4, and 0 mm, with particle sedimentation rates of 0.149, 0.019, 0.017, and 0 mm/h, respectively. The MRF with high dispersion stability was obtained, and the etching of CIP by HCl and the proper chain length of the coating of silane coupling agent were proved effective manners to improve the dispersion stability of MRF.

Non-Settling Super-Strong Magnetorheological Fluids

A magnetorheological (MR) fluid is generally called a suspension in which magnetic particles are dispersed in a non-magnetic medium. When an external magnetic field is applied, a pseudo-phase transition occurs within a short time to generate yield stress, and when the magnetic field is released, it returns to the suspended state. Due to these unique characteristics, it is classified as a smart material to be widely applied in various industries. High performance MR fluids require high yield stress and stability for long-term use. However, it is very difficult to improve performance and stability simultaneously due to the limited amount of magnetic particles in the suspension and particle sedimentation caused by the density mismatch between the suspending particles and the liquid phase. In this study, an MR slurry is developed that is completely different from the MR suspension, starting from the opposite concept. An innovative non-settling (i.e., permanently stable) magnetorheological slurry is successfully created that exhibits unprecedented ultra-high yield stress. This result is expected to be a turning point for applying MR fluids to more diverse industries. In addition, a simple fitting equation expressing the yield stress as a function of the particle volume fraction is proposed.

Rheological Tunable Magnetic Fluids with Long-Term Stability

Magnetic fluids have advantages such as flow ability and solid-like property in strong magnetic fields, but have to suffer from the tradeoff between suspension stability and flow resistance. In this work, a thermal/photo/magnetorheological water-based magnetic fluid is fabricated by using oleic acid-coated Fe₃ O₄ (Fe₃ O₄ @OA) nanoparticles as the magnetic particles and the amphiphilic penta block copolymer (PTMC-F127-PTMC)-based aqueous solution as the carrier fluid. Due to the hydrophobic self-assembly between Fe₃ O₄ @OA and PTMC-F127-PTMC, the Newtonian-like magnetic fluid has outstanding long-term stability and reversible rheological changes between the low-viscosity flow state and the 3D gel structure. In the linear viscoelastic region, the viscosity exhibits an abrupt increase from below 0.10 Pa s at 20 °C to ≈1.3 × 10⁴  Pa s at 40 °C. Benefitting from the photothermal and magnetocaloric effects of the Fe₃ O₄ @OA nanoparticles, the rheological change process also can be controlled by near infrared light and alternating magnetic field, which endows the magnetic fluid with the applications in the fields of mobile valves, moveable switches, buffer or damping materials in sealed devices, etc.

Stable Magnetorheological Fluids Containing Bidisperse Fillers with Compact/Mesoporous Silica Coatings

A drawback of magnetorheological fluids is low kinetic stability, which severely limits their practical utilization. This paper describes the suppression of sedimentation through a combination of bidispersal and coating techniques. A magnetic, sub-micro additive was fabricated and sequentially coated with organosilanes. The first layer was represented by compact silica, while the outer layer consisted of mesoporous silica, obtained with the oil–water biphase stratification method. The success of the modification technique was evidenced with transmission electron microscopy, scanning electron microscopy/energy-dispersive X-ray spectroscopy and Fourier-transform infrared spectroscopy. The coating exceptionally increased the specific surface area, from 47 m2/g (neat particles) up to 312 m2/g, which when combined with lower density, resulted in remarkable improvement in the sedimentation profile. At this expense, the compact/mesoporous silica slightly diminished the magnetization of the particles, while the magnetorheological performance remained at an acceptable level, as evaluated with a modified version of the Cross model. Sedimentation curves were, for the first time in magnetorheology, modelled via a novel five-parameter equation (S-model) that showed a robust fitting capability. The sub-micro additive prevented the primary carbonyl iron particles from aggregation, which was projected into the improved sedimentation behavior (up to a six-fold reduction in the sedimentation rate). Detailed focus was also given to analyze the implications of the sub-micro additives and their surface texture on the overall behavior of the bidisperse magnetorheological fluids.

Stiffness enhancement of magnetorheological foam by structural modification using silica nanoparticles additive

Magnetorheological (MR) foam is a newly developed porous smart material that is able to change its properties continuously, actively, and reversibly in response to controllable external magnetic stimuli. Unfortunately, the stiffness or also known as storage modulus of MR foam is still rather low and insufficient, in the range of below 100 kPa only, due to weak interparticle interaction between CIPs and the foam matrix, which consequently restricts the potential of MR foam to be used in future sensor applications or in other semi-active devices. Therefore, the aim of this research is to enhance the structural and storage modulus of MR foam by adding silica nanoparticles as an additive. Consequently, MR foam samples with different compositions of silica nanoparticles in the range of 0–5 wt% were prepared via an in situ method. The rheological properties were tested under an oscillatory shear mode with the absence and presence of magnetic fields using a rheometer, with the input parameters of strains between 0.001% and 10% and range of magnetic flux density between 0 and 0.73 T for a magnetic field sweep test. The rheological findings show that with the addition of silica nanoparticles, particularly at 4 wt%, have enhanced the storage modulus of MR foam by 260%, which attributed to the highest stiffness from 45 to 162 kPa. Meanwhile, the change of storage modulus under the influence of magnetic fields (0 T–0.73 T) somehow showed small increment, about ∆1 kPa for each concentration of silica nanoparticles in MR foams, due to non-magnetic behavior of silica. The morphological characteristics of MR foams were described by an elemental analysis carried out by a using variable pressure scanning electron microscope (VPSEM) equipped with energy dispersive x-ray spectroscopy (EDX). The micrographs demonstrated large open-cell pores for MR foam, while MR foam with silica nanoparticles exhibited more closed-cell pores, associated with the enhancement of its storage modulus. It indicates that the silica nanoparticles have encouraged well dispersion of the particles in the foam matrix, which improved and strengthened the microstructure of MR foams through formation of silane coupling bonds of silica in the filler-matrix structure. Overall, incorporation of silica nanoparticles as an additive in the MR foam could provide advantage in enhancing the structure and mechanical properties of MR foam, for various future smart devices.

High performance magnetorheological fluids: very high magnetization FeCo-Fe3O4 nanoclusters in a ferrofluid carrier

High magnetization Fe₃O₄/OA-FeCo/Al₂O₃ nanocomposite magnetic clusters have been obtained using a modified oil-in-water miniemulsion method. These nanocomposite clusters dispersed in a ferrofluid carrier result in a magnetorheological fluid with improved characteristics. The magnetic clusters have a magnetic core consisting of a mixture of magnetite nanoparticles of about 6 nm average size, stabilized with oleic acid (Fe₃O₄/OA) and FeCo/Al₂O₃ particles of about 50 nm average size, compactly packed in the form of spherical clusters with a diameter distribution in the range 100-300 nm and a hydrophilic coating of sodium lauryl sulphate surfactant. The surface chemical composition of the Fe₃O₄/OA-FeCo/Al₂O₃ clusters investigated by XPS indicates the presence of the Co²⁺ and Co³⁺ oxidation states of cobalt and the components of Fe²⁺ and Fe³⁺ characteristic to both an enhanced oxidation state at the surface of the FeCo particles and to the presence of magnetic nanoparticles of spinel structure which are decorating the supporting FeCo. This specific decorating morphology is also indicated by TEM images. Advanced characterization of the Fe₃O₄/OA-FeCo/Al₂O₃ magnetic clusters has been performed using Mössbauer spectroscopy and magnetization measurements at various temperatures between 6 K and 200 K. The unexpected formation of Co ferrite decorating nanoparticles was supported by Mössbauer spectroscopy. The dispersion of magnetic clusters in the ferrofluid carrier highly influences the flow properties in the absence of the field (shear thinning for low and moderate shear rates) and especially in applied magnetic field, when significant magnetoviscous effect and shear thinning was observed for the whole range of shear rate values. Detailed analysis of the magnetorheological behavior of the nanocomposite magnetic clusters dispersed in a ferrofluid carrier evidence significantly higher normalized dynamic yield stress values in comparison with the magnetite nanocluster suspensions of the same mass concentration, a promising result for this new type of nanocomposite magnetorheological fluid.

Synergistic Effects of Nonmagnetic Carbon Nanotubes on the Performance and Stability of Magnetorheological Fluids Containing Carbon Nanotube-Co0.4Fe0.4Ni0.2 Nanocomposite Particles

We investigated the magnetorheological (MR) properties of the carbon nanotube (CNT)-Co_0.4Fe_0.4Ni_0.2 composite suspension to find a high-performance MR fluid with excellent stability. The composites were fabricated by chemical reduction of Co_0.4Fe_0.4Ni_0.2 on the surface of amine-functionalized CNTs. A synergistic effect between the high aspect ratio of the CNTs and the strong magnetic polarization of the Co_0.4Fe_0.4Ni_0.2 led to stronger MR performance of the nanocomposite particle suspension. The MR fluid exhibits an unexpected high yield stress value that is 13 times greater than that of a CNT-Fe₃O₄ suspension at a magnetic field strength of 343 kA/m. Nonmagnetic CNTs form a three-dimensional networklike structure, imparting surprisingly large additional yield stress to the CNT-Co_0.4Fe_0.4Ni_0.2 nanocomposite MR suspension. The low density of the CNTs resulted in much better long-term stability for the CNT-Co_0.4Fe_0.4Ni_0.2 nanocomposite suspension than the MR fluid containing only Co_0.4Fe_0.4Ni_0.2.

Strong and Stable Magnetorheological Fluids Based on Flaky Sendust-Co0.4Fe0.4Ni0.2 Nanocomposite Particles

The magnetorheological (MR) performance of suspensions based on magnetic (flaky Sendust (FS))-magnetic (Co_0.4Fe_0.4Ni_0.2) nanocomposite particles was investigated by using a vibrating sample magnetometer and a rotational rheometer. Flaky Sendust@Co_0.4Fe_0.4Ni_0.2 nanocomposite particles were fabricated through wet chemical synthesis of Co_0.4Fe_0.4Ni_0.2 on the surface of FS. The density of the resultant FS@Co_0.4Fe_0.4Ni_0.2 was less than that of FS due to the pore/void formation in the composite particles. Because of the high saturation magnetization of Co_0.4Fe_0.4Ni_0.2 (165 emu/g), FS@Co_0.4Fe_0.4Ni_0.2 (145 emu/g) exhibited greater magnetization than bare FS (130 emu/g), which resulted in the good performance of FS@Co_0.4Fe_0.4Ni_0.2-based MR fluids: the suspension exhibited a remarkably high yield stress, almost one order greater than that of MR fluids based on hierarchically structured (HS) Fe₃O₄ particles. In addition, the high drag coefficient of FS@Co_0.4Fe_0.4Ni_0.2 in the liquid medium, in conjunction with its lower density, resulted in a substantially improved long-term stability, better than that of Co_0.4Fe_0.4Ni_0.2- or FS-based suspensions. Although the density of the FS@Co_0.4Fe_0.4Ni_0.2 nanoparticles is higher than that of HS-Fe₃O₄ particles, their stability is much better than the stability of HS-Fe₃O₄ particle's suspension. Manufactured magnetic-magnetic nanocomposite particles provide a feasible MR suspension of high MR performance and long-term stability.

Magnetorheological fluids based on core-shell carbonyl iron particles modified by various organosilanes: synthesis, stability and performance

Although smart materials, specifically magnetorheological (MR) fluids, have shown remarkable practical importance, their drawbacks such as an aggregation of magnetic fillers, insufficient compatibility with the carrier liquid, low resistance to corrosion and poor sedimentation stability still cause severe limitations for their broader utilization. To address this challenge, our study presents a facile concept for the coating of magnetic particles, leading to their enhanced utility properties and sufficient MR performance. This concentrates on the coating of magnetic carbonyl iron (CI) particles with a thin modifying layer as a surface shell utilizing four organosilanes; tetraethoxysilane, (3-aminopropyl)triethoxysilane, bis[3(trimethoxysilyl)propyl]amine and vinyltrimethoxysilane. Characterization of the modified particles and their suspensions was examined using various methods. XPS analysis confirmed the successful particle modification, while the surface free energy was evaluated by tensiometric measurements reflecting the better compatibility of particles with the dispersing medium. The lowest surface free energy possessed particles modified with (3-aminopropyl)triethoxysilane. The magnetization of the modified core-shell particles was not negatively affected by the organosilanes layer present on the particles resulting in comparable MR performance of the systems based on pure CI particles and their modified analogues as was proved by the fitting of the corresponding flow curves by the Robertson-Stiff model. Moreover, the modification of the particles improved their thermo-oxidation stability and chemical stability investigated via thermogravimetric analysis and acidic tests, respectively. Finally, the sedimentation stability of the modified particle-based systems expressed as a weight gain measured using a tensiometer device was enhanced in comparison with the pure CI particle-based system, which can be very positive in the intended applications.

Magnetorheological Elastomers: Fabrication, Characteristics, and Applications

Magnetorheological (MR) elastomers become one of the most powerful smart and advanced materials that can be tuned reversibly, finely, and quickly in terms of their mechanical and viscoelastic properties by an input magnetic field. They are composite materials in which magnetizable particles are dispersed in solid base elastomers. Their distinctive behaviors are relying on the type and size of dispersed magnetic particles, the type of elastomer matrix, and the type of non-magnetic fillers such as plasticizer, carbon black, and crosslink agent. With these controllable characteristics, they can be applied to various applications such as vibration absorber, isolator, magnetoresistor, and electromagnetic wave absorption. This review provides a summary of the fabrication, properties, and applications of MR elastomers made of various elastomeric materials.

Bio-Inspired Passion Fruit-like Fe3O4@C Nanospheres Enabling High-Stability Magnetorheological Performances

Magnetorheological (MR) fluids have been successfully utilized in versatile fields but are still limited by their relatively inferior long-term dispersion stability. Herein, bio-inspired passion fruit-like Fe₃O₄@C nanospheres were fabricated via a simple hydrothermal and calcination approach to tackle the settling challenge. The unique structures provide sufficient active interfaces for the penetration of carrier mediums, leading to preferable wettability between particles and medium oils. Compared with the bare Fe₃O₄ nanoparticle suspension, the resulting Fe₃O₄@C nanosphere-based MR fluid exhibits desirable stability and relatively low field-off viscosity even at a high particle concentration up to 35 vol %.

Multiresponsive Hybrid Microparticles for Stimuli-Responsive Delivery of Bioactive Compounds

Hybrid microparticles based on an iron core and an amphiphilic polymeric shell have been prepared to respond simultaneously to magnetic and ultrasonic fields and variation in the surrounding pH to trigger and modulate the delivery of doxorubicin. The microparticles have been developed in four steps: (i) synthesis of the iron core; (ii) surface modification of the core; (iii) conjugation with the amphiphilic poly(lactic acid)-grafted chitosan; and (iv) doxorubicin loading. The particles demonstrate spherical shape, a size in the range of 1–3 µm and surface charge that is tuneable by changing the pH of the environment. The microparticles demonstrate good stability in simulated physiological solutions and are able to hold up to 400 µg of doxorubicin per mg of dried particles. The response to ultrasound and the changes in the shell structure during exposure to different pH levels allows the control of the burst intensity and release rate of the payload. Additionally, the magnetic response of the iron core is preserved despite the polymer coat. In vitro cytotoxicity tests performed on fibroblast NIH/3T3 demonstrate a reduction in the cell viability after administration of doxorubicin-loaded microparticles compared to the administration of free doxorubicin. The application of ultrasound causes a burst in the release of the doxorubicin from the carrier, causing a decrease in cell viability. The microparticles demonstrate in vitro cytocompatibility and hemocompatibility at concentrations of up to 50 and 60 µg/mL, respectively.

Effects of Al3+ on the microstructure and bioflocculation of anoxic sludge

The aluminum ions generated from mining aluminum, electrolytic aluminum and the industrial production of aluminum-based coagulants (such as AlCl₃ and Al₂(SO₄)₃) enter sewage treatment plants and interact with activated sludges. An anaerobic/anoxic/oxic (A²O) process was used to reveal the effects of Al³⁺ on the pollutant removal efficiencies, bioflocculation and the microstructure of sludge. The results showed that a low concentration of Al³⁺ improved the pollutant removal efficiencies and increased the sludge particle size. However, a high concentration of Al³⁺ hindered microbial flocculation and reduced the pollutant removal efficiencies. With a 10 mg/L Al³⁺ addition, the chemical oxygen demand (COD), total nitrogen (TN) and NH₄⁺-N increased by 3%, 16% and 27%, and reached as high as 68%, 60% and 87%, respectively. At the same time, the dehydrogenase activity, flocculation ability (FA) and contact angle of the sludge reached their maximum levels at 41.3 mg/L/hr, 45% and 79.63°, respectively. The specific surface area of the sludge decreased to 7.084 m²/g and the sludge pore size distribution shifted to concentrate in the mesoporous range. Most of Al³⁺ was adsorbed on the surface of sludge, changing the physicochemical properties and physical structure of the sludge.

Searching for a Stable High-Performance Magnetorheological Suspension

Magnetorheological (MR) fluids are a type of smart material with rheological properties that may be controlled through mesostructural transformations. MR fluids form solid-like fibril structures along the magnetic field direction upon application of a magnetic field due to magnetopolarization of soft-magnetic particles when suspended in an inert medium. A reverse structural transition occurs upon removal of the applied field. The structural changes are very fast on the order of milliseconds. The rheological properties of MR fluids vary with the application of a magnetic field, resulting in non-Newtonian viscoplastic flow behaviors. Recent applications have increased the demand for MR materials with better performance and good long-term stability. A variety of industrial MR materials have been developed and tested in numerous experimental and theoretical studies. Because modeling and analysis are essential to optimize material design, a new macroscale structural model has been developed to distinguish between static yield stress and dynamic yield stress and describe the flow behavior over a wide range of shear rates. Herein, this recent progress in the search for advanced MR fluid materials with good stability is described, along with new approaches to MR flow behavior analysis. Several ways to improve the stability and efficiency of the MR fluids are also summarized.

High-Performance Magnetorheological Suspensions of Pickering-Emulsion-Polymerized Polystyrene/Fe3O4 Particles with Enhanced Stability

The magnetorheological (MR) performance of suspensions based on core-shell-structured foamed polystyrene (PSF)/Fe₃O₄ particles was investigated by using a vibrating sample magnetometer and a rotational rheometer. Core-shell-structured polystyrene (PS)/Fe₃O₄ was synthesized by using the Pickering-emulsion polymerization method in which Fe₃O₄ nanoparticles were added as a solid surfactant. Foaming the PS core in PS/Fe₃O₄ particles was carried out by using a supercritical carbon dioxide (scCO₂) fluid. The density was measured by a pycnometer. The densities of PS/Fe₃O₄ and PSF/Fe₃O₄ particles were significantly lowered from that of the pure Fe₃O₄ particle after Pickering-emulsion polymerization and foaming treatment. All tested suspensions displayed similar MR behaviors but different yield strengths. The important parameter that determined the MR performance was not the particle density but rather the surface density of Fe₃O₄ on the PS core surface. The morphology was observed by scanning electron microscopy and transmission electron microscopy. Most Fe₃O₄ particles stayed on the surface of PS/Fe₃O₄ particles, making the surface topology bumpy and rough, which decreased the particle sedimentation velocity. Finally, Turbiscan apparatus was used to examine the sedimentation properties of different particle suspensions. The suspensions of PS/Fe₃O₄ and PSF/Fe₃O₄ showed remarkably improved stability against sedimentation, much better than the bare Fe₃O₄ particle suspension because of the reduced density mismatch between the nanoparticles and the carrier medium as well as the surface topology change.

Carbonyl iron coated with a sulfobetaine moiety as a biocompatible system and the magnetorheological performance of its silicone oil suspensions

In this study, surface modification of carbonyl iron (CI) particles with sulfobetaine moieties (SBE) was performed by the silanization of activated CI to form stable CI–SBE particles.