Magnetic Surfactant Research Articles

Single-domain structure of Fe3O4 nanoparticles encapsulation by magnetic surfactant M(AOT)2 (M=Co, Ni)

Investigating the magnetic nanoparticle size and the effective magnetic interactions that form the magnetic domain can lead us to nanoparticles with targeted applications, such as targeted drug delivery and higher resolution MRI imaging. In this study magnetic susceptibility and coercive field properties, and the structure size range of single-domain magnetic capsules with high magnetization were obtained by structural analysis of volumetric DLS properties. In this regard, the role of exchange, anisotropy, and magnetostatic interaction was investigated in the structure of a magnetic capsule containing Fe3O4 nanoparticles (MCap-NPs). The stable capsules were synthesized in an emulsion solution with magnetic surfactants M(AOT)2 (M = Co, Ni). Vibrating Sample Magnetometer (VSM) and capsule relative volume (CRV) of Dynamic Light Scattering (DLS) were used to determine the magnetic properties of the single-domain (SD) structure. The produced emulsion samples were found to have superparamagnetic properties property with saturation magnetization in the range of 2–6 × 10−3emu/g for NiCap-NPs, and 5-13 × 10−3emu/g for CoCap-NPs. The results show that nanoparticles have the most significant effect on magnetization. The coercive field, the anisotropy energy values, and the SD of M(AOT)2 were determined using magnetic susceptibility distribution. The outcome results show that the surface of the magnetic capsule plays an essential role in forming a single-domain structure. It was also found that the saturation magnetization of the samples in the emulsion solution is proportional to the nanoparticle density and not to the mass of nanoparticles. All produced samples have distinct peaks in CRV versus capsule size, and each peak follows a log-normal distribution. For both samples, except for the samples with molar ratios ω of 23 (Co3 and Ni4 samples), the positions of the second and third relative volume peaks were constant at 269 ± 3 nm and 424±6 nm, respectively. The behavior of the CRV function normalized to the peak size showed a proportionality between the coercive field and the CRV.

Study on the adsorption efficiency and mechanism of Sb(V) in aqueous solutions using enhanced surfactant-modified iron-calcium composite

The presence of Sb(V) in aqueous solutions poses a significant threat to the surrounding environment, and current treatment methods are inadequate. In this study, a magnetic surfactant (CTAB)-modified iron-calcium composite (CTAB-IC) was successfully synthesized using iron-calcium composite as the base material. This novel composite was used for the efficient removal of Sb(V) from textile wastewater solutions. Characterization analyses revealed that the CTAB-IC material exhibits a rich long-prismatic structure and superparamagnetic properties, classifying it as a soft magnetic material. Post-adsorption particle agglomerates were found to comprise Ca, S, and O. Sequential batch experiments demonstrated a maximum adsorption capacity of 54.05 mg/g, with adsorption kinetics data fitting the pseudo-second-order model. The intraparticle diffusion model indicated the presence of multiple diffusion steps during the adsorption process. Additionally, the adsorption of Sb(V) by CTAB-IC was identified as a heterogeneous surface adsorption process, best described by the Freundlich model. The primary adsorption mechanisms involved the formation of surface Ca-O-Sb complexes and inner-sphere Fe-O-Sb complexes, as well as amorphous surface precipitation and electrostatic adsorption. Notably, the treatment of textile wastewater often results in iron-calcium-rich sludge, which is challenging to manage and valorize. This study explored the potential for resource recycling by utilizing CTAB to harness the Fe elements in textile wastewater sludge, thereby promoting waste-to-resource conversion.

Tribological properties of pickering emulsion constructed with ZnO nanoparticles modified by magnetic surfactants

To fulfill the requirements of long-term stable lubrication and corrosion protection, conventional industrial emulsion lubricants often involve complex formulations with multiple components, posing challenges in terms of preparation, recycling, and potential environmental impact. In order to address the problems, a Pickering emulsion with a simple composition and excellent anti-corrosion properties is prepared by incorporating magnetic surfactant ((C18H37)2N+(CH3)2[CeCl4]-) modified ZnO nanoparticles as a multifunctional additive into colza oil and water. The results demonstrate that Pickering emulsions exhibit excellent stability. Moreover, their magnetic responsiveness makes them promising candidates for intelligent lubricants. Furthermore, effective recycling and sustainability are achieved through reversible emulsification and demulsification. Tribological test results reveal that the addition of modified ZnO enhances the emulsions’ anti-friction and anti-wear properties due to nanoparticle rolling and repairing effects, generation of tribofilms, and deposition of ZnO nanoparticles. We anticipate that the Pickering emulsion could find widespread applications in various sectors, including metalworking and industrial manufacturing, owing to its uncomplicated composition, environmentally friendly nature, excellent anti-corrosion capabilities, and superior lubricating properties.

Effect of magnetic field and surfactant on the boiling heat transfer and CHF of magnetic nanofluids on a downward heating surface

In this study, boiling heat transfer experiments on downward heating surface with different concentrations of magnetic nanofluids (α-Fe2O3 and γ-Fe2O3 nanofluids) was explored, through adding surfactants and applying external magnetic fields to enhance the critical heat flux (CHF). The CHF of each group of experiments was compared with that of the water condition. The results revealed that the surfactants cetyltrimethylammonium bromide (CTAB) and ethylene glycol (EG) as well as the magnetic field could improve the CHF of the magnetic nanofluid. And, surfactants improve the dispersion of the magnetic nanofluids. Specifically, under the magnetic field, 0.005 g/L of γ-Fe2O3/EG-water nanofluid showed the largest CHF enhancement of 34.0 % compared to the aqueous condition. Furthermore, the mechanism behind enhancing CHF of magnetic nanofluids was discussed by analyzing the modification of nanofluids, the deposition on the heating surface, and the behavior of bubbles during the experimental process.

Phenol degradation and Sb(V) adsorption by superparamagnetic CTAB-modified iron calcium composite

The heavy metal ions and organic dyes in textile wastewater treatment pose a significant environmental burden and are challenging to effectively manage. A magnetic cationic surfactant hexadecyltrimethylammonium bromide (CTAB), modified iron-calcium composite (referred to as CIC), was prepared using a straightforward method from iron-calcium composites as raw materials. The simultaneous catalytic degradation and adsorption efficiency of phenol and Sb(V) from textile wastewater were evaluated using this material. The results indicate that under conditions of pH 5.0 and a duration of 180 min, both phenol and Sb(V) removal rates exceed 90%. Characterization and experimental findings reveal that CIC possesses magnetic properties, facilitating easy separation, and offers a large surface area, ensuring abundant adsorption sites and stability. Additionally, CIC can assist in the enhanced degradation of phenol by H2O2. Pseudo-second-order kinetics describe the adsorption of Sb(V) by CIC, while oxidative kinetics explain the degradation of phenol. The primary removal mechanisms involve the oxidation and degradation of phenol through the generation of hydroxyl radicals by H2O2 and the formation of Fe-O-Sb complexes between Sb(V) and the iron sites on CIC, as well as the precipitation of Ca-O-Sb compounds between Sb(V) and the calcium sites on CIC. Therefore, the synergistic effect of CIC and H2O2 offers an efficient and environmentally friendly method for the simultaneous removal of Sb(V) and phenol in coupled wastewater, presenting broad prospects for application in wastewater treatment.

Magnetic nanoparticles and cationic surfactants for the extraction and determination of phenolic compounds in environmental and biological samples

Magnetic nanoparticles and cationic surfactants for the extraction and determination of phenolic compounds in environmental and biological samples

Multiheaded Cationic Surfactants with Dedicated Functionalities: Design, Synthetic Strategies, Self-Assembly and Performance.

Contemporary research concerning surfactant science and technology comprises a variety of requirements relating to the design of surfactant structures with widely varying architectures to achieve physicochemical properties and dedicated functionality. Such approaches are necessary to make them applicable to modern technologies, such as nanostructure engineering, surface structurization or fine chemicals, e.g., magnetic surfactants, biocidal agents, capping and stabilizing reagents or reactive agents at interfaces. Even slight modifications of a surfactant's molecular structure with respect to the conventional single-head-single-tail design allow for various custom-designed products. Among them, multicharge structures are the most intriguing. Their preparation requires specific synthetic routes that enable both main amphiphilic compound synthesis using appropriate step-by-step reaction strategies or coupling approaches as well as further derivatization toward specific features such as magnetic properties. Some of the most challenging aspects of multicharge cationic surfactants relate to their use at different interfaces for stable nanostructures formation, applying capping effects or complexation with polyelectrolytes. Multiheaded cationic surfactants exhibit strong antimicrobial and antiviral activity, allowing them to be implemented in various biomedical fields, especially biofilm prevention and eradication. Therefore, recent advances in synthetic strategies for multiheaded cationic surfactants, their self-aggregation and performance are scrutinized in this up-to-date review, emphasizing their applications in different fields such as building blocks in nanostructure engineering and their use as fine chemicals.

Application of Novel Magnetic Surfactant-Based Drilling Fluids for Clay Swelling Inhibition

Water-based drilling fluids are widely employed in the oilfield industry for the efficient and smooth drilling of wellbore reservoirs. In this study, a novel drilling formulation was prepared by mixing a magnetic surfactant in the base mud formulation. Several drilling fluid tests were conducted, which include steady shear and dynamic rheology, filtration, clay sedimentation, clay swelling, and particle size distribution analysis. Different analytical techniques─XRD, FTIR, and TGA analyses─were performed to study the interactions of magnetic surfactant with the clay platelets. The experimental results of the surfactant-modified formulations were compared to the base mud formulation. Thermal gravimetric analysis of the surfactant-modified mud showed improved thermal stability compared to the base mud. FTIR analysis results of the base mud and surfactant-modified mud were compared. In the steady shear rheology experiments, the flow curves of the base mud and surfactant-modified mud showed that the addition of surfactant in the base mud affects the shear stress of formulation. The shear stress data of rheology was fitted to the Herschel–Bulkley model, and model parameters trends were assessed with and without the addition of surfactant in the base mud. Shale inhibition tests showed that the incorporation of magnetic surfactant minimized the clay hydration of swelling, thus proving a superior shale inhibitor. The particle size analysis showed that the average particle size of clay particles increased with the increasing concentration of the magnetic surfactant. The linear swelling analysis of clay showed that the rate of swelling was 90% in the surfactant-modified mud as compared to the swelling rate in deionized water. According to the zeta potential, the combination of surfactants significantly affects the electrokinetic behavior of dispersion. Further, the XRD proved that the interlayer spacing of clay increasing while interacting with magnetic surfactant molecules indicates the ability of magnetic surfactant as a shale swelling and hydration inhibitor for water-based drilling formulations.

Ballistic Ejection of Microdroplets from Overpacked Interfacial Assemblies (Adv. Funct. Mater. 20/2023)

Magnetic Nanoparticle Surfactants In article number 2213844, Thomas P. Russell, Dong Wang, Ahmad K. Omar, and co-workers illustrate that external magnet (not shown) induces a moment (shown by arrows) in iron oxide nanoparticles dispersed in an aqueous droplet and an oversaturation of nanoparticles on the surface of the droplet. Removal of the magnetic field causes an explosive ejection of ferromagnetic liquid microdroplets from the surface of the droplet. The authors dedicate this contribution to the memory of Phillip L. Geissler, an exceptional colleague, scientist and collaborator without whom this work would not have been possible.

A Magnetic Surfactant Having One Degree of Unsaturation in the Hydrophobic Tail as a Shale Swelling Inhibitor

One of the foremost causes of wellbore instability during drilling operations is shale swelling and hydration induced by the interaction of clay with water-based mud (WBM). Recently, the use of surfactants has received great interest for preventing shale swelling, bit-balling problems, and providing lubricity. Herein, a novel synthesized magnetic surfactant was investigated for its performance as a shale swelling inhibitor in drilling mud. The conventional WBM and magnetic surfactant mixed WBM (MS-WBM) were formulated and characterized using Fourier Transform Infrared (FTIR) and Thermogravimetric analyzer (TGA). Subsequently, the performance of 0.4 wt% magnetic surfactant as shale swelling and clay hydration inhibitor in drilling mud was investigated by conducting linear swelling and capillary suction timer (CST) tests. Afterward, the rheological and filtration properties of the MS-WBM were measured and compared to conventional WBM. Lastly, the swelling mechanism was investigated by conducting a scanning electron microscope (SEM), zeta potential measurement, and particle size distribution analysis of bentonite-based drilling mud. Experimental results revealed that the addition of 0.4 wt% magnetic surfactant to WBM caused a significant reduction (~30%) in linear swelling. SEM analysis, contact angle measurements, and XRD analysis confirmed that the presence of magnetic surfactant provides long-term swelling inhibition via hydrophobic interaction with the bentonite particles and intercalation into bentonite clay layers. Furthermore, the inhibition effect showed an increase in fluid loss and a decrease in rheological parameters of bentonite mixed mud. Overall, the use of magnetic surfactant exhibits sterling clay swelling inhibition potential and is hereby proffered for use as a drilling fluid additive.

Self-Assembly of a C16M[Mn] Magnetic Surfactant in Water.

A magnetic surfactant, which combines the properties of a surfactant with magnetic responsiveness, shows great potential in biotechnology, separation, adsorption, and catalysis, especially in non-invasive manipulation through a magnetic field. However, a molecularly magnetic surfactant is usually paramagnetic for the amorphous and less ordered structures. In this work, magnetic surfactant 1-methyl-3-hexadecane-imidazolium [MnCl2Br] (C16M[Mn]) is reported to self-assemble in water. The C16M[Mn] magnetic surfactant self-assembles in water to form a lamellar hydrogel from 10 to 50 wt % at and below room temperature. The hydrogel changes from a gel to a sol at 30 °C, and the hexadecane chains in the hydrogel change from noncrystalline to crystalline at 0 °C. In the hydrogel state, the lamellar domain spacing is varied from 36 to 45 nm depending on the concentration and self-assembly temperature. After self-assembly, the magnetic susceptibility of the freeze-dried magnetic surfactant is increased. Most important is the fact that the freeze-dried sample at a high concentration (40-50 wt %) shows the highest magnetic susceptibility, which is related to the closer molecular packing and the more ordered structures. The self-assembly-induced increase in magnetic susceptibility provides a method for improving the magnetic properties of a magnetic surfactant.

Surfactant-Modified Silica Nanoparticles-Stabilized Magnetic Polydimethylsiloxane-in-Water Pickering Emulsions for Lubrication and Anticorrosion

Traditional industrial lubricating emulsions usually contain a variety of constituents to fulfill their functional requirements in long-term stability, lubrication, and anticorrosion. The complexity of the constituents may produce difficulties for their preparation, storage, and recycling. To address this issue, here we design and prepare simple-component, switchable, and multifunctional Pickering emulsions using the green lubricating base oil polydimethylsiloxane, water, and silica nanoparticles modified with a series of magnetic surfactants (CnH2n+1N+(CH3)3[XCl3Br]−, n = 12, 14, and 16, X = Ce, Fe, and Gd) as compositions. The Pickering emulsions are demonstrated to be highly stable, lubricative, and anticorrosive. Their magneto-responsiveness indicates a potential application as smart lubricants. Their reversible emulsification and demulsification, which allows an effective recycling and reuse of the composite nanoparticles, can be regulated by alternative centrifugation and homogenization or successive addition of the anionic surfactant sodium dodecyl sulfate and the magnetic cationic surfactants. Both their stability and lubricity can be optimized by using surfactant C16H33N+(CH3)3[CeCl3Br]− (CTACe) as the surface coating for the silica particles. The deposition of CTACe-modified silica nanoparticles endows a metallic material with a high resistance to abrasion and corrosion. We envision that such emulsions, consisting of eco-friendly, biocompatible, and low-cost materials, could find extensive applications in sustainable chemistry and engineering.

Influence of the diameter of the magnetic core and surfactant thickness on water carrying iron (iii) oxide ferrofluid flow over a rotating disk

Analysis of ferrofluid over a rotating plate is very important in the field of biomedical sciences, electronic devices, and aerodynamics. This work investigates the influence of the diameter of the magnetic core and thickness of the surfactant layer on water-carrying iron(iii) oxide ferrofluid flow and heat transfer over a rotating disk in the presence of a stationary magnetic field. The nonlinear differential equations for velocity and temperature are solved numerically using the finite element procedure. The validation of the present numerical solution is also demonstrated. The non-Newtonian results under the influence of stationary magnetic field for velocity and temperature profiles are compared with the Newtonian results of velocity and temperature profiles in the absence of the magnetic field. Increasing the diameter size of the iron(iii) oxide nanoparticles reduces the velocity and temperature in the flow. However, the thickness of the surfactant layer enhances the velocity and temperature. However, the magnetic field produces the shear thickening in the flow. Enhancement in the diameter of the iron (iii) oxide nanoparticles increases the stress on the disk and local heat transfer, and enhancement in the thickness of the surfactant layer of the nanoparticles reduces the stress and local heat transfer.

Magnetoresponsive biocomposite hydrogels comprising gelatin and valine based magnetic ionic liquid surfactant as controlled release nanocarrier for drug delivery

A strategic nanoparticle-free approach towards construction of magnetoresponsive biocomposite hydrogels is presented.

Effect of the diameter of magnetic core and surfactant thickness on the viscosity of ferrofluid

The diameter of the magnetic core and thickness of the surfactant layers have an important role in the viscosity of ferrofluid. These factors are not reported in the previous theoretical investigations properly. We presented the graphical results of these critical factors in the present analysis. The present study describes the theoretical results of the viscosity without the magnetic field due to the variation in the diameter of the magnetic core and the thickness of the surfactant layer. The rotational viscosity in the presence of the stationary and alternating magnetic field is also presented. The results show that increasing the magnetic core’s diameter reduces the viscosity of ferrofluid and increasing the thickness of the surfactant layer increases the viscosity. It is also observed that a stationary magnetic field always enhances the viscosity of ferrofluids and in the case of an alternating magnetic field, the viscosity of ferrofluids depends not only on the strength but also on the frequency of the field.

Highly dispersible magnetic nanoparticles modified by double quaternary ammonium surfactants for efficient harvesting of oleaginous microalgae

Microalgae have been known as a promising sustainable resource for bioenergy cleaner production. Herein, a series of highly dispersible novel magnetic quaternary ammonium cationic surfactants (Fe3O4@DQn, n = 1, 2, 3) for the efficient harvesting of oleaginous Chlorella pyrenoidosa (C. pyrenoidosa) have been investigated. The Fe3O4@DQn capture microalgae process can be divided into a three-step operation (i.e., flocculation, separation, and recycle). For harvesting C. pyrenoidosa, the Fe3O4@DQn has both a high recovery efficiency (>98.4%) and a short flocculation time (2 min). In addition, the reused Fe3O4@DQ2 can maintain a high recovery efficiency (92.31%) with five cycling times. Moreover, the N-[3-(Trimethoxysilyl)propyl]ethylenediamine (TMPED) amount and the pH value both have a positive influence on the C. pyrenoidosa harvesting. It is worth noting that the dual effect of quaternary ammonium cationic surfactant, strong positively charged and hydrophobic properties, leads to a higher harvesting efficiency of microalgae. Furthermore, the results of particle size distribution and turbiscan stability index (TSI) show that a higher specific surface area, a smaller polydispersity index and TSI value of the Fe3O4@DQn can make a more excellent adsorption and dispersion properties. Finally, the Fe3O4@DQn might provide a promising high cost-performance to harvesting of oleaginous microalgae due to the better economic viability.

Synthesis and evaluation of magnetic surfactants for high temperature oilfield application

Magnetic surfactants are a unique class of amphiphiles that can manage self-assembly in a controlled manner in the presence of the applied magnetic field. However, any surfactant for oilfield application must be soluble in water and exhibit high heat stability as it needs to stay in harsh reservoir conditions. Herein, we report a synthesis of two new magnetic surfactants that contain different hydrophobic moieties (ethoxylated alky tail and oleic tail). The chemical structures of the magnetic surfactants and their nonmagnetic parent surfactants were elucidated by ESI-MS, NMR (1H, 13C), and FTIR analysis. Both surfactants display good aqueous solubility due to the insertion of ethoxy units and unsaturation in the hydrophobic tail. The effect of hydrophobic tails on heat and surface/interface properties was investigated. Rendering to thermal gravimetric curves, the degradation temperature of magnetic surfactants was near 270 °C. This clearly showed that the magnetic surfactants contain high thermal stability for elevated temperature reservoirs. However, the effect of change of hydrophobic tail appears to be insignificant in thermal stability tests. An analysis of the surface tension showed that magnetic surfactants were more effective than corresponding nonmagnetic surfactants exhibiting higher surface tension (γ) reduction of water even with no magnetic field. Moreover, the magnetic surfactant containing an ethoxylated alkyl tail showed more surface tension (γ) reduction of water than a magnetic surfactant with an oleic tail. The research outcome on the synthesized magnetic surfactants makes them an attractive choice in a harsh oilfield environment. To the best of our knowledge, this is the first report on the magnetic surfactants that can toleratate high temperature reservoir conditions.

Inhibitive Effect on the Rate of Hydrolysis of Tetracaine by the Surfactant-Coated Magnetic Nanoparticles (Fe3O4)

The influence of the magnetic nanoparticles Fe3O4 and surfactant coated nanoparticles on the rate of alkaline hydrolysis of tetracaine were investigated spectrophotometrically. The Fe3O4 nanoparticles were synthesized by co-precipitation method. These synthesized nanoparticles were characterized by physical techniques. The XRD patterns showed the crystalline nature and the presence of two bands at 635 cm -1 and 585 cm -1 were assigned to the Fe-O bond vibrations in Fe3O4. The SEM and TEM studies confirmed the spherical structure of nanoparticles. The VSM studies show the magnetic nature. The reaction rate increased linearly with increase in [NaOH]. The rate constant values decreased with the increase in the SDS coated Fe3O4 nanoparticles from 4.0 × 10 -4 s -1 to 1.1 × 10 -4 s -1 in the presence of PEG 1500. Similarly, the increase in the amount of CTABr coated Fe3O4 nanoparticles decreased the rate constant values from 4.0 × 10 -4 s -1 to 1.02 × 10 -4 s -1 in the presence of PEG 1500. The binding constant and rate constant were found to be lower in SDS coated nanoparticles than the CTABr coated particles. The observed results for - [surfactant] in the presence of magnetic nanoparticles and surfactant coated nanoparticles were treated using the pseudophase kinetic model.

Magnetic Microemulsions Stabilized by Alkyltrimethylammonium-Based Magnetic Ionic Liquids Surfactants (MILSs)

While traditional microemulsions are versatile media for nanoscience and nanotechnology, stimulus-responsive microemulsions are more challenging to realize, and only a handful of cases have been reported. We here introduce magnetic microemulsions (MMEs) stabilized by alkyltrimethylammonium-based magnetic ionic liquids surfactants (MILSs), paired with water as the polar phase, aliphatic oils as the nonpolar phase, and aliphatic alcohols as the cosurfactant. n-Hexane coupled with n(MILSs/1-butanol) = 1:4 showed the most excellent ability to form MMEs, and the range of the monophasic region was expanded with increasing alkyl chain length of MILSs cation. Classical oil-in-water (O/W), bicontinuous (BC) sponge structure, and inverse water-in-oil (W/O) subregions were clarified by conductivity method. Dynamic light scattering showed that the diameter of W/O microemulsions droplets were about 2-6 nm. Magnetic susceptibility and rheological measurements revealed that these MMEs are with high magnetic susceptibility and low viscosity, which show interesting potential applications based on a manipulation via external magnetic field. Moreover, these MMEs showed Newtonian-like flow behavior within respective subregions, and their magnetic susceptibility was not affected by the subregion structure but MILSs mass fraction.

Preparation of a novel magnetorheological fluid for high temperatures.

Magnetorheological fluids, especially those in high-power magnetorheological devices, inevitably work at high temperatures because of the wall slip, energized coils and frictions between particles. In order to prepare a magnetorheological fluid for high temperatures, this work investigates the properties of three main components (soft magnetic particles, surfactants and base carrier fluids) for a magnetorheological fluid at high temperatures. On this basis, a novel magnetorheological fluid for high temperatures is prepared. Its sedimentation stability, viscosity and shear yield stress are investigated at high temperatures. The results show that the novel magnetorheological fluid has acceptable sedimentation, suitable viscosity and stable shear yield stress at high temperatures. The novel magnetorheological fluid for high temperatures can be applied to most magnetorheological devices, especially high-power magnetorheological devices.