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Poly(amide-ether)/NiFe2O4 nanocomposites with different amounts of NiFe2O4 were synthesized by the solution intercalation method. Poly(amide-ether) (12) derived from dibenzo xanthene was prepared by condensation reaction of N-(3-(14H-dibenzo[a,j]xanthen-14-yl)phenyl)-3,5-diaminobenzamide (7) and 4,4′-(ethane-1,2-diylbis(oxy))dibenzoic acid (10) monomers. The poly amide-ether (PAE) was characterized by Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1H-NMR), ultraviolet–visible spectroscopy (UV–vis), and thermogravimetric analysis (TGA). The intrinsic viscosity of PAE in DMF solution, with a concentration of 0.01 g/dL at a temperature of 25 °C, was found to be 0.31 dL/g−1. NiFe2O4 nanoparticles were prepared via the co-precipitation method and used for the preparation of new poly(amide-ether)/NiFe2O4 nanocomposites (PAEN 3% and PAEN 5%). The morphology, crystalline phase, thermal stability, and magnetization properties of the prepared nanocomposites were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), UV–vis, TGA, DSC, and vibrating sample magnetometer (VSM). The SEM measurements show that the diameter of the NiFe2O4 nanoparticles is about 40 nm. The XRD results indicated the formation of NiFe2O4 nanoparticles with cubic phase in the PAE matrix. In examining the optical properties, it has been observed that by increasing the NiFe2O4 nanoparticle concentration, PAEN 3% and PAEN 5% nanocomposites show a decrease in wavelength and have a blue shift of 2 and 4 nm, respectively, compared to pure PAE. The magnetic properties of the sample were showed that the sample exhibited typical ferromagnetic behavior at room temperature. Also, results of TGA measurement have shown that the incorporation of NiFe2O4 in a higher concentration in the PAE matrix revealed improved thermal stability when compared to the neat PAE. The results indicate that the prepared nanocomposites exhibited magnetic properties and improvement in the thermal stability compared to neat PAE. [ABSTRACT FROM AUTHOR]

Adsorption and photocatalytic decolorization methods were used to remove Reactive Orange 16 dye from textile wastewater by using ethyleneglycoldimethacrylate and 1-vinyl-1,2,4-triazole, m-poly(EGDMA-VTA)-TiO2 polymer composite particles with magnetic synthesized by suspension polymerization. The characterization of the synthesized m-poly(EGDMA-VTA)-TiO2 particules were carried out by using XRD, FTIR, SEM–EDS-elemental mapping, ESR, and BET analyses. Both adsorption and photocatalytic decolorization processes of RO16 dye were applied to the polymer particles. The effects of solution pH, amount of adsorbent, initial dye concentration, temperature, and time on the adsorption capacity were investigated. The removal of R016 dye reached a maximum at pH 3. Dye substance removal decreased due to increasing temperature and adsorbent amount. As a result of experimental studies, the adsorption of RO16 dye was explained by the Langmuir isotherm, while its kinetics was stated by a pseudo-second-order mechanism. Additionally, thermodynamic functions (ΔHo, ΔGo, and ΔSo) have been determined. At the end of adsorption, the decolorization kinetics were elucidated by examining the adsorbent amount, time, and dye concentration parameters for the photocatalytic decolorization of non-adsorbed dyes. It was determined that the photocatalytic activity was highest at low dye concentration and high photocatalyst content. Additionally, it was determined that decolorization kinetics studies were compatible with the Langmuir–Hinshelwood model. [ABSTRACT FROM AUTHOR]

This work reports the engineering of the magnetic properties of composites based on acrylonitrile butadiene styrene (ABS) by the inclusion of different magnetic nanoparticles (MNP). ABS‐based composites with different MNP, including permalloy, Fe3O4, CoFe2O4, Ni, and Co‐carbon coated, with a 10 wt% content have been prepared and their morphological, electric, thermal, magnetic, and mechanical properties evaluated. Films were processed by solvent casting under two different processing conditions, no magnetic field applied during solvent evaporations, and an out‐of‐plane magnetic field application. It is shown that ABS‐based composites preserve the magnetic properties of the filler, providing a simple way to tune the magnetic behavior in the polymer. The inclusion of permalloy, Fe3O4, CoFe2O4, Ni, and Co‐carbon coated fillers, allow to obtain saturation magnetizations of 6.2, 4.1, 7.3, 3.7, 4.4, and 4.9 emu/g, respectively, and coercive fields of 88.5, 30.9, 128, 2529.8, 123.6, and 197.4 Oe, respectively. It was found that the mechanical properties of the composites depend on filler type and dimensions, maintaining the thermoplastic behavior of the matrix when the fillers are small (up to 40 nm) and losing it when the fillers are bigger (from 60 to 135 nm). Further, the breaking stress, elongation at break, and the Young's modulus are material dependent, showing higher values when the fillers are Fe3O4 and CoFe2O4 and lower values when the fillers are permalloy, Ni, and Co‐carbon; for example, these values are the highest in the case of the ABS‐Fe3O4 composite with values of 28.7 MPa, 4.1%, and 1266.9 MPa, respectively, while ABS‐Co composite shows the lowest breaking stress and elongation at break with 9.2 MPa and 1.5%, respectively. The ABS‐permalloy composite presents the lowest Young's modulus with 781.5 MPa. Also, the magnetic fillers do not change significantly the thermal, dielectric, and the electrical properties of the composites at this concentration (10 wt%). Overall, the present work demonstrates the feasibility of the modulation of the mechanical and the tuning of the magnetic properties of ABS‐based magnetic nanocomposites by changing the magnetic material and by applying a magnetic field during the processing of the composites, allowing their application in areas including sensors, actuators, and magnetic devices. Highlights: Magnetic nanoparticles can engineer the magnetic properties in a composite.Nanoparticles (NP) can engineer mechanical properties depending on their material.NP can engineer mechanical properties depending on their dimensions.With this process, the thermal, electric, and dielectric properties are preserved.Applied magnetic fields during solvent evaporations affects the Young's modulus. [ABSTRACT FROM AUTHOR]

Silk fibroin (SF) is an interesting biomaterials with intriguing mechanical, optical, piezoelectric, and biocompatible properties. The present study reports the first magnetic experiments to show that organic radicals in the building blocks of SF induce permanent magnetization in these materials. A saturation magnetization of 2.8 × 10−3 emu g−1 and non‐zero remnant magnetization of 2.2 × 10−4 emu g−1 with a coercive field of 65 Oe is observed in multiple SFs. Tightly bound β‐sheets of polyglycine‐alanine motifs provides sufficient steric hinderance to organic radicals and protects them from attack of reactive species. Moreover, it also shows that silk's ferromagnetic character can be enhanced by simple mechanical stretching and heating. This work demonstrates a new paradigm of magnetic proteins and opens a route toward the biomimetic discovery of iron‐free magnetic proteins. [ABSTRACT FROM AUTHOR]

Abstract Magnetic actuation has attracted a growing attention due to its non‐contact performance, rapid response and penetrability. The realization of magnetic actuation requires the participation of magneto‐responsive materials (MRMS), and magneto‐responsive polymers (MRPs) are one of the most widely used MRMs. Here, we report the fabrication, characterization and actuation tests of neodymium‐iron‐boron‐polydimethylsiloxane (NdFeB‐PDMS) magnetic films. The NdFeB‐PDMS magnetic film has great flexibility and elasticity, as well as excellent magnetism. The film also shows exceptional deformation and magnetic controllability under magnetic actuation. Besides, it can be driven under a very low magnetic field down to 1mT, and generate an out‐of‐plane displacement of 2.7 mm under the action of magnetic fields. We focus on the tensile deformation of NdFeB‐PDMS films under magnetic driving and provide a possible design for their potential application in the tensile loading system. Preliminary tests demonstrate that the size of tensile deformation is adjusted by controlling the output signal and amplification factor. Highlights Fabrication of NdFeB‐PDMS magnetic films. Mechanical and magnetic characterizations of NdFeB‐PDMS films. Magnetic actuation tests of NdFeB‐PDMS films. Magnetic field‐induced tensile deformation of NdFeB‐PDMS films. Potential application of NdFeB‐PDMS films in the tensile loading system.

Smart polymers synthesized from renewable sources are precious because of the environmental pressures of producing polymers from fossil fuels. This study develops a new formulation of polyurethane (PU) from partly renewable resources. PU composites were prepared from castor oil (CO), polyethylene glycol (PEG3000), and hexamethylene diisocyanate (HDI). CO was used as both polyol and crosslinker. Butanediol and/or low molecular weight polyethylene glycol (PEG300) were added to the reaction medium as a chain extender. As a magnetic particle, natural magnetite or carbonyl iron was used in various amounts (0–10%). Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), scanning electron microscope (SEM), optical microscope, and goniometer were used to characterize all composites and pure PU. A bending test was applied to investigate the shape fixity and shape recovery ratios of the samples. A range of hydrophilic/hydrophobic PU composites (water contact angle is between 56–87°) having various melting and glass transition temperatures were successfully prepared. A PU composite having a good shape recovery ratio (Rr = 96.1%) in a magnetic field was prepared using 10% magnetite. The PU composites were also thermosensitive.

The development of polymeric composites that possess both exceptional electromagnetic interference shielding effectiveness (EMI SE) and high absorption capacity has always been appealing, yet it continues to pose a significant challenge. To this end, we disclose a hollow and spherical shielding unit that could achieve "absorption‐reflection‐attenuation" process for incident electromagnetic (EM) wave, which was fabricated through decorating Ni nanoparticles onto rGO hollow microspheres by virtue of Pickering emulsification method followed by thermal annealing. With integrated magnetic and electric parts, the consequent shielding composite by assembling these microspheres into PDMS displayed not only a favorable EMI SE of 44 dB across the entire x‐band, but also significantly improved absorption performance that has exceeded 95% of the total SE. Moreover, the power coefficient of absorption (A) is up to 0.73 at the pyrolysis temperature of 550°C. Such admirable performance is mainly attributed to the synergistic effect of conductive rGO walls, magnetic Ni nanoparticles, as well as the unique spherical architecture, which has enabled more efficient capture and attenuation of EM waves. Herein, this research has highlighted the development of polymeric composites for high‐performance EMI shielding applications. Highlights: Reflection‐absorption‐integrated shielding compartment was designed.Decorating magnetic Ni nanoparticles onto rGO hollow microspheres.High EMI SE with enhanced absorption ability was acquired.Unique structure generating synergistic effect on EMI shielding [ABSTRACT FROM AUTHOR]

Magnetic actuation has attracted a growing attention due to its non‐contact performance, rapid response and penetrability. The realization of magnetic actuation requires the participation of magneto‐responsive materials (MRMS), and magneto‐responsive polymers (MRPs) are one of the most widely used MRMs. Here, we report the fabrication, characterization and actuation tests of neodymium‐iron‐boron‐polydimethylsiloxane (NdFeB‐PDMS) magnetic films. The NdFeB‐PDMS magnetic film has great flexibility and elasticity, as well as excellent magnetism. The film also shows exceptional deformation and magnetic controllability under magnetic actuation. Besides, it can be driven under a very low magnetic field down to 1mT, and generate an out‐of‐plane displacement of 2.7 mm under the action of magnetic fields. We focus on the tensile deformation of NdFeB‐PDMS films under magnetic driving and provide a possible design for their potential application in the tensile loading system. Preliminary tests demonstrate that the size of tensile deformation is adjusted by controlling the output signal and amplification factor. Highlights: Fabrication of NdFeB‐PDMS magnetic films.Mechanical and magnetic characterizations of NdFeB‐PDMS films.Magnetic actuation tests of NdFeB‐PDMS films.Magnetic field‐induced tensile deformation of NdFeB‐PDMS films.Potential application of NdFeB‐PDMS films in the tensile loading system. [ABSTRACT FROM AUTHOR]

Nanocomposite of magnetic Fe3O4 nanoparticles and polypyrrole was prepared under sonication by a new chemical polymerization method during which Fe3O4 nanoparticles acted both as a pyrrole oxidant and as a component in the composite material. Synthesis of this nanocomposite was carried out in aqueous solution acidified to pH 2, a prerequisite for the formation of these types of material and to facilitate pyrrole oxidation by Fe3O4 nanoparticles. In this way, two kind of materials were produced: Fe3O4/PPy nanocomposite in which magnetite nanoparticles were dispersed in PPy matrix and Fe3O4-aggregates@PPy nanocomposite that exhibits structure in which aggregates of magnetite nanoparticles are surrounded by a layer of polymeric phase. In the latter case, the polymerization process took place in the presence of a surfactant. These nanocomposites were characterized by electron microscopy techniques, IR spectroscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy and thermogravimetry. Particular attention was focused on the study of the electrochemical properties of the formed composites. The composite of Fe3O4 and PPy exhibits reversible electrochemical behaviour upon oxidation. The electrode process of the polymeric component oxidation in organic solvents such as acetonitrile and dichloromethane is very similar to the process in an aqueous solution. [ABSTRACT FROM AUTHOR]

Smart polymers synthesized from renewable sources are precious because of the environmental pressures of producing polymers from fossil fuels. This study develops a new formulation of polyurethane (PU) from partly renewable resources. PU composites were prepared from castor oil (CO), polyethylene glycol (PEG3000), and hexamethylene diisocyanate (HDI). CO was used as both polyol and crosslinker. Butanediol and/or low molecular weight polyethylene glycol (PEG300) were added to the reaction medium as a chain extender. As a magnetic particle, natural magnetite or carbonyl iron was used in various amounts (0--10%). Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), scanning electron microscope (SEM), optical microscope, and goniometer were used to characterize all composites and pure PU. A bending test was applied to investigate the shape fixity and shape recovery ratios of the samples. A range of hydrophilic/hydrophobic PU composites (water contact angle is between 56-87°) having various melting and glass transition temperatures were successfully prepared. A PU composite having a good shape recovery ratio (Rr = 96.1%) in a magnetic field was prepared using 10% magnetite. The PU composites were also thermosensitive. [ABSTRACT FROM AUTHOR]

The magnetic properties of a polyfluorene derivative, {Poly[9,9'‐dihexylfluorene‐2,7‐yl)‐3,8‐(1,10‐phenanthroline)]} and its complexes with neodymium ions are explored and discussed in the light of the macromolecular configuration and photophysical properties. The pristine noncomplexed material is a diamagnetic material, and the introduction of Nd atoms in the polymer leads to a paramagnetic behavior over the entire temperature range. The prominent role of the morphology is demonstrated by comparison of two forms, with different ligands to the metal: one with bulky β‐diketone groups and another with small chorine as ligands. The large groups hinder interchain interaction, whereas the smaller salt forms favored interchain π‐stacking, providing a better interaction of the magnetic field with the polymer backbone, resulting in enhanced magnetic properties. The form with the β‐diketone groups exhibits a paramagnetic behavior whereas the one in the salt form presents ferromagnetic behavior at room temperature. This contribution brings solid confirmation to the importance of interchain interaction in the magnetic properties of conjugated polymers, opening a new way to the obtainment of magnetic conjugated polymers. [ABSTRACT FROM AUTHOR]

The use of iron oxide nanoparticles for the synthesis of adsorbents materials with application in contaminated water remediation is based on both their magnetic and adsorption properties. Poly(styrene-co-divinylbenzene) - Poly(Sty-co-DVB)microparticles are widely known for this use and the addition of magnetite comes to add magnetic properties, however it should not limit the functionalization processes for formation of cationic and/or anionic resins. Thus, there is a concern about the stability of magnetite in acidic environments, as required by the sulfonation process, for example. Furthermore, the synthesis of composites with magnetic nanoparticles is a challenge due to the strong magnetic dipole interactions between particles resulting from the high specific surface area, making them susceptible to aggregation. As well as oxidation during the synthesis process can compromise the structure of the initial magnetic material. In this sense, the present work validated processes for the synthesis of Poly(Sty-co-DVB)/magnetite microparticles that sought, as a final result, the incorporation of magnetite aiming to preserve its initial structural conformation. Thus, started from original synthesis method aimed at the production of Poly(Sty-co-DVB) microparticles without magnetite, to methods in which magnetite nanoparticles is added through two distinct processes, different regarding the use or not of oleic acid in its preparation.In this method article we show: • Combination of methods to preserve the structure of magnetite in the Poly(Sty-co-DVB)/magnetite composite. • Simple method of adding magnetite to the Poly(Sty-co-DVB)/magnetite composite synthesis process. • Magnetite treatment method with oleic acid in Poly(Sty-co-DVB)/magnetite composite synthesis.The samples were characterized using Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and Mössbauer spectroscopy to evaluate the chemical modifications that were introduced in the original synthesis method.

The present work is aimed at designing innovative hybrid materials endowed with magnetic features. To this end, polymer beads are used as matrix for the encapsulation of Magnetic Microparticles (MMPs). The inorganic part of developed hybrids consists of MMPs (i.e., magnetite- Fe3O4), whereas the organic part consists of two-component polymer beads, obtained using poly (acrylonitrile-co-methacrylic acid) and polyvinyl alcohol. Magnetite particles are characterized in terms of both particle size and zeta potential by Dynamic Light Scattering (DLS), while their crystallite size and phases are assessed by X-ray Diffraction. The developed innovative hybrid materials are fully characterized using the following techniques: Fourier Transform Infrared (FTIR) spectrometry; Thermogravimetric Analysis/ Differential Thermal Analysis (TG/DTA) and Scanning Electron Microscopy (SEM). Furthermore, their magnetic properties are assessed using a Vibrating Sample Magnetometer (VSM) and their capacity for adsorption of active principles. In this respect, resveratrol, a poorly soluble, bioactive compound, was chosen as model active principle and it was found that the developed hybrids may achieve an efficient binding of resveratrol. [ABSTRACT FROM AUTHOR]

Magnetophoresis offers many advantages for manipulating magnetic targets in microsystems. The integration of micro-flux concentrators and micro-magnets allows achieving large field gradients and therefore large reachable magnetic forces. However, the associated fabrication techniques are often complex and costly, and besides, they put specific constraints on the geometries. Magnetic composite polymers provide a promising alternative in terms of simplicity and fabrication costs, and they open new perspectives for the microstructuring, design, and integration of magnetic functions. In this review, we propose a state of the art of research works implementing magnetic polymers to trap or sort magnetic micro-beads or magnetically labeled cells in microfluidic devices [ABSTRACT FROM AUTHOR]

Magnetophoresis offers many advantages for manipulating magnetic targets in microsystems. The integration of micro-flux concentrators and micro-magnets allows achieving large field gradients and therefore large reachable magnetic forces. However, the associated fabrication techniques are often complex and costly, and besides, they put specific constraints on the geometries. Magnetic composite polymers provide a promising alternative in terms of simplicity and fabrication costs, and they open new perspectives for the microstructuring, design, and integration of magnetic functions. In this review, we propose a state of the art of research works implementing magnetic polymers to trap or sort magnetic micro-beads or magnetically labeled cells in microfluidic devices.

The degrees of spin labeling of a polyphenylene-based polymer and its graphitized derivative with a stable nitronyl nitroxide were evaluated by estimating the absolute numbers of spins in a set of samples using continuous wave (CW) electron spin resonance (ESR). For these particular systems, the degrees of spin labeling were found to be approximately 0.8% and 1.3%, respectively. The developed procedure complements the more advanced time-resolved/cryogenic ESR studies on these systems by focusing on the stable spin labels introduced in these magnetically intricate materials and providing an estimate of their absolute amount, which is indispensable in the development of synthetic approaches to prepare modified graphene systems and for evaluating the success of these systems. [ABSTRACT FROM AUTHOR]

Poly[9,9′‐dihexylfluorene‐2,7‐diyl)‐6,6″‐(2,2′:6′,2″‐terpyridine)] (LaPPS75) and its complexes with neodymium were synthesized and characterized. Magnetic measurements showed that the noncomplexed polymer presented a ferromagnetic contribution due to the formation of π stacking, and that in absence of those, the ferromagnetic behavior is suppressed. The pristine polymer, the complexed one and a low‐molecular‐weight model compound with the same structure of the complexed site in the parent polymer were studied. The observed behavior found is presented and discussed, the most important finding was that when a conjugated chain is used as a host for the metallic ion, an amplification of four times for the magnetization is achieved, using the same metallic content for complexed polymer and model compound for comparison. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 304–311 The magnetic properties of an alternated copolymer of fluorene‐terpyridine complexed with neodymium were studied. The results showed important differences as compared to a low‐molecular‐weight model compound and to a noncomplexed parent copolymer as well. An amplification of four times for the magnetization was achieved with the insertion of the metallic ion. The π stacking of the pristine copolymer played an important role in the magnetic properties of the pristine copolymer. [ABSTRACT FROM AUTHOR]

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Polymetallocenes based on ferrocene, and to a lesser extent cobaltocene, have been well‐studied, whereas analogous systems based on nickelocene are virtually unexplored. It has been previously shown that poly(nickelocenylpropylene) [Ni(η5‐C5H4)2(CH2)3]n is formed as a mixture of cyclic (6x) and linear (7) components by the reversible ring‐opening polymerisation (ROP) of tricarba[3]nickelocenophane [Ni(η5‐C5H4)2(CH2)3] (5). Herein the generality of this approach to main‐chain polynickelocenes is demonstrated and the ROP of tetracarba[4]nickelocenophane [Ni(η5‐C5H4)2(CH2)4] (8), and disila[2]nickelocenophane [Ni(η5‐C5H4)2(SiMe2)2] (12) is described, to yield predominantly insoluble homopolymers poly(nickelocenylbutylene) [Ni(η5‐C5H4)2(CH2)4]n (13) and poly(tetramethyldisilylnickelocene) [Ni(η5‐C5H4)2(SiMe2)2]n (14), respectively. The ROP of 8 and 12 was also found to be reversible at elevated temperature. To access soluble high molar mass materials, copolymerisations of 5, 8, and 12 were performed. Superconducting quantum interference device (SQUID) magnetometry measurements of 13 and 14 indicated that these homopolymers behave as simple paramagnets at temperatures greater than 50 K, with significant antiferromagnetic coupling that is notably larger in carbon‐bridged 6x/7 and 13 compared to the disilyl‐bridged 14. However, the behaviour of these polynickelocenes deviates substantially from the Curie–Weiss law at low temperatures due to considerable zero‐field splitting. Ring‐opening polymerisation (ROP) of tetracarba[4]nickelocenophane and disila[2]nickelocenophane to yield predominantly insoluble homopolymers, and the reversible nature of this ROP at elevated temperature is described. SQUID magnetometry indicated that the homopolymeric materials behave as simple paramagnets at T> 50 K, with significant antiferromagnetic coupling, but deviate substantially from the Curie–Weiss law at low temperatures. [ABSTRACT FROM AUTHOR]

Magnetostriction effect, i.e., deformation under the action of a uniform applied field, is analyzed to detail for a spherical sample of a magnetoactive elastomer (MAE). A close analogy with the field-induced elongation of spherical ferrofluid droplets implies that similar characteristic effects viz. hysteresis stretching and transfiguration into a distinctively nonellipsoidal bodies, should be inherent to MAE objects as well. The absence until now of such studies seems to be due to very unfavorable conclusions which follow from the theoretical estimates, all of which are based on the assumption that a deformed sphere always retains the geometry of ellipsoid of revolution just changing its aspect ratio under field. Building up an adequate numerical modelling tool, we show that the ‘ellipsoidal’ approximation is misleading beginning right from the case of infinitesimal field strengths and strain increments. The results obtained show that the above-mentioned magnetodeformational effect should distinctively manifest itself in the objects made of quite ordinary MAEs, e.g., composites on the base of silicone cautchouc filled with micron-size carbonyl iron powder.

Materials that exhibit the photo-induced magnetic-phase transition of titania are receiving significant attention because they can be easily switched between diamagnetism and paramagnetism by UV irradiation. However, it is difficult to store photo-induced titanium (Ti3+) in air because of its easy oxidation upon oxygen exposure. In this study, titania/polycarbonate hybrid films were prepared using linear 1,6-hexanediol (PHMCD), cyclic 1,4-cyclohexanedimethanol (PCHCD), or their copolymerized carbonate oligomers using the sol–gel method. The oxygen permeability of the hybrid film decreased as the ratio of the ring structure increased by a factor of approximately 32 from PHMCD with only the chain structure to PCHCD with only the ring structure. These hybrid films can generate Ti3+ under a UV irradiation of 250 W for 2 h, and the difference in oxygen permeability significantly affected the lifetime of the Ti3+ by a factor of up to 120. In addition, the tensile tests and IR measurements demonstrated that UV irradiation had little effect on the mechanical intensity and matrix chemical structure. Moreover, the magnetic susceptibility of Ti3+ present in PCHCD was confirmed to be 6.2 (10−3 emu/g(titania)) under an external magnetic field of 5 T induced using a superconducting quantum interference device.

Metal-free ferromagnetic materials have gained significant attention as an appealing alternative to traditional inorganic magnets due to their biocompatibility, biodegradability, low production cost, flexibility, solubility in organic solvents, and electrical insulation properties. These features make them highly desirable for biomedical and spintronic applications. The origin of magnetism in these materials is linked to the presence of unpaired electrons, defects, or functional groups that induce local magnetic moments. However, achieving ferromagnetic interaction among persistent carbon radicals within a molecule has been a challenging endeavor. Various strategies have been explored to induce ferromagnetism in carbon-based materials, including defect induction, steric hindrance, and doping with trivalent or pentavalent species like Boron (B) and Nitrogen (N). These approaches have successfully led to the development of organic magnets in different dimensions, ranging from 0D to 3D. Recent advancements in synthesizing organic magnets exhibiting ferromagnetism above room temperature have reignited interest among physicists and chemists in the realm of organic spintronic materials. Furthermore, the integration of magnetic nanoparticles into carbon nanotubes has been a prominent research focus. Understanding the underlying mechanisms of magnetism in carbon-based polymers, such as graphene, carbon nanotubes, and fullerenes, has been the subject of extensive studies over the past few decades. This article presents a critical review of recent research on carbon-based magnetic polymers, including their limitations and applications. The emergence of magnetism in carbon-based 2D materials holds immense potential for spintronics and high-density data storage applications, contributing to the advancement of quantum computing and empowering artificial intelligence. • Recent critical review in carbon-based magnetic fiber materials with applications. • Core concepts of magnetism and characterization techniques. • Fundamentals of organic magnets including molecular and polymer magnets. • Critics on magnetism of graphene and other carbon allotropes. [ABSTRACT FROM AUTHOR]

Abstract Polymeric magnetic hybrid materials (PMHM) are a motivating research topic for microactuator technologies, as flexible magnetic devices or contactless manipulation, useful for many applications. However, the control of these microactuators remains a challenge due to the severe performances required and the nonlinear dynamics that typify them. This study performs an exhaustive experimental characterization of the nonlinear dynamics of a PMHM-film as a cantilever actuator. The PMHM-film consists of polyvinyl butyral (PVB) with iron oxide (Fe 2 O 3) nanoparticles synthesized in-situ , at two different nominal concentrations of FeCl 2 ·4H 2 O. This work presents the synthesis of the PMHM-films (PVB/Fe 2 O 3), their magnetic and morphological characterization, and the dynamic characterization at constant and sine magnetic fields. Magnetic characterization showed a superparamagnetic-like behavior of the material at room temperature, in accordance with previous works. A damped-like behavior is exposed with a maximum displacement of 0.99 mm when a constant magnetic field of 0.96 kOe is applied. In the sine magnetic field test, a nonlinear response and rate-dependent behavior when the frequency is increased were observed. Future work will consider the physical model of the dynamic behavior of the (PVB/Fe 2 O 3) films and a control system to reduce the hysteresis nonlinearities. [ABSTRACT FROM AUTHOR]

Abstract: Poly(aminoamide) (PAMAM) dendrimer with 3.5 generation was synthesized with ethylenediamine as the primary core and methyl acrylate. Also, Fe3O4 nanoparticles as magnetic ones were modified by (3‐aminopropyl)triethoxysilane (APTES) to fabricate amine‐functionalized magnetic nanoparticles (Fe3O4@APTES). Then, 3.5GD dendrimer was conjugated with Fe3O4@APTES to obtain dendrimer‐grafted magnetic nanoparticles (Fe3O4@3.5GD). The core‐shell structure of Fe3O4@3.5GD nanoparticles was revealed via TEM. Also, progression of each step was studied by FT‐IR, 1H NMR, CHN elemental analysis, and thermal gravimetric analysis (TGA). Vibrating sample magnetometer (VSM) was used to show that the synthesized nanoparticles keep their superparamagetic properties after synthesis process. Finally, in vitro cellular cytotoxicity was applied to evaluate the biocompatibility of synthesized structures and investigate the cytotoxic effect of grafted dendrimer using HeLa cells. As a resultS, about 20 wt. % of dendrimer grafting was obtained and good correlation was observed with VSM results. Also, 3.5GD dendrimer showed low cytotoxicity to HeLa cells while after dendrimer grafting, toxicity of Fe3O4@3.5GD slightly increased. [ABSTRACT FROM AUTHOR]

Three types of super paramagnetic core-shell nanoparticles have creatively been synthesized via three basic substances, Fe 2+ /Fe 3+ , methacrylic acid (MAA), and 2,2′-azobisisobutyronitrile (AIBN). It has been demonstrated that the order of addition of starting materials determines the type of products. Methacrylic acid coated magnetic nanoparticles (Fe 3 O 4 @MAA) with abundant double bonds on the surface, poly methacrylic acid coated magnetic nano particles (Fe 3 O 4 @PMAA) having plenty of surface carboxylic groups, and amphiphilic shell of methacrylic acid polymer on magnetic nano particles core (Fe 3 O 4 @AMPH) having both carboxyl and alkyl groups on the surface were prepared in three, separate one-pot, sequential synthesis. At first, the resultant magnetic nanoparticles (MNPs) were characterized by transmission electron microscopy (TEM), dynamic light scattering, X-ray spectroscopy, Fourier transform infrared spectroscopy (FTIR) and thermal analysis. Then, the colloidal stability of the synthesized particles was investigated in several common solvents such as water, 1-propanol, chloroform, and edible oil. Finally, the application of each nanoparticle was discussed. It was found that Fe 3 O 4 @MAA can be successfully applied as a core in polymerization procedure. Fe 3 O 4 @PMAA performed well in nickel uptake and can therefore be used as magnetic solid sorbent in nickel pre-concentration and remediation. Fe 3 O 4 @AMPH was well dispersed in oil, suggesting that it can be successfully used as a good extractor in dispersive solid phase pre-concentration and cleanup of both hydrophilic and hydrophobic compounds in heated edible oil samples. [ABSTRACT FROM AUTHOR]

ABSTRACT: In the current research, the sonochemically prepared magnetite nanoparticles (MNPs) were silylated with triethoxyvinylsilane to produce a core–shell structure containing vinyl moieties on the surface. The radical polymerization of the silylated product with acrylic acid in the presence of N,N‐methylenebisacrylamide, as the cross‐linker, led to the formation of novel magnetic hydrogel nanocomposites (MHNCs) in which some of polyacrylic acid (PAA) chains were chemically grafted onto MNPs (PAA‐grafted MNPs). Vibrating sample magnetometry showed the unique phenomenon of superparamagnetism for the prepared MNPs, silylated MNPs, and PAA‐grafted MNPs. Batch adsorption experiments were carried out for the removal of methylene blue (MB) using pure hydrogel and MHNCs as an adsorbent. The effects of contact time, PAA‐grafted MNP content, adsorbent mass, and initial pH value of the dye solution on adsorption were investigated. Results showed the MHNC containing 10 wt% of PAA‐grafted MNP (MHNC 10 wt%) had the maximum adsorption capacity. It was observed that the adsorption kinetics of MB followed pseudo–second‐order kinetics. The adsorption equilibrium data obeyed Langmuir isotherm, and the maximum adsorption amount of MB reached 507.7 mg g–1 for MHNC 10 wt%. It was shown that the adsorbed MB could be desorbed from the MHNCs by using methanol solution containing acetic acid and the nanoadsorbents could be recycled. [ABSTRACT FROM AUTHOR]

The idea of creating magnetically controllable colloids whose rheological properties can be finely tuned on the nano- or micro-scale has caused a lot of experimental and theoretical effort. The latter resulted in systems whose building blocks are ranging between single magnetic nanoparticles to complexes of such nanoparticles bound together by various mechanisms. The binding can be either chemical or physical, reversible or not. One way to create a system that is physically bound is to let the precrosslinked supracolloidal magnetic polymers (SMPs) to cluster due to both magnetic and Van-der-Waals-type forces. The topology of the SMPs in this case can be used to tune both magnetic and rheological properties of the resulting clusters as we show in this work. We employ Molecular Dynamics computer simulations coupled with explicit solvent modelled by Lattice-Boltzmann method in order to model the behaviour of the clusters formed by chains, rings, X- and Y-shaped SMPs in a shear flow with externally applied magnetic field. We find that the shear stabilises the shape of the clusters not letting them extend in the direction of the field and disintegrate. The clusters that show the highest response to an applied field and higher shape stability are those made of Y- and X-like SMPs. • Clusters of sticky magnetic polymers are investigated in the flow. • The angle between the field and the flow alters cluster deformations. • Polymer topology changes magneto-rheological response of clusters. • Clusters show potential for directional transport on the nanoscale. [ABSTRACT FROM AUTHOR]

Magnetics nanoparticles (NPMs) has found many applications in biomedical and technological areas. The objective of this work is the preparation and characterization of PMMA microspheres containing NPMs coated with oleic acid (NPMs-AO). For the preparation of MNPs-AO was used the coprecipitation method in an aqueous medium. For the preparation of the superparamagnetic microspheres used in suspension polymerization technique. The microspheres showed a size distribution particles of approximately 150um and a spherical morphology. From the analysis of gel permeation chromatography (GPC) determined the number average molecular weight (Mw) of the magnetics microspheres and there was a variation in the Mw depending on the concentration of MNPs-AO in this reaction. To analyze the magnetic properties used the vibrating sample magnetometer (MAV). The microspheres showed superparamagnetic properties and a value of saturation magnetization (Ms) of about 8 emu/g MNPs. Therefore you can conclude that it is possible to obtain superparamagnetics microspheres for a particular application, either, biomedical or technological.

The degrees of spin labeling of a polyphenylene-based polymer and its graphitized derivative with a stable nitronyl nitroxide were evaluated by estimating the absolute numbers of spins in a set of samples using continuous wave (CW) electron spin resonance (ESR). For these particular systems, the degrees of spin labeling were found to be approximately 0.8% and 1.3%, respectively. The developed procedure complements the more advanced time-resolved/cryogenic ESR studies on these systems by focusing on the stable spin labels introduced in these magnetically intricate materials and providing an estimate of their absolute amount, which is indispensable in the development of synthetic approaches to prepare modified graphene systems and for evaluating the success of these systems.

An example how to benchmark magnetic composites made of LSR, Liquid Silicone Rubber and magnetic filler for a potential application is given. A characteristic degree of filling was revealed appearing in viscosity, density and magnetic permeability investigations, consistently. A simple model is proposed to describe the magnetic permeability as a function of the degree of filling requiring only one adjustable parameter. [ABSTRACT FROM AUTHOR]

Norbornene-derived copolymer with side-chain phosphonic acid and cationic motifs (NORP-PHOS-CAT copolymer) are synthesized using ring opening metathesis polymerization method. All the monomers and polymers are characterized very carefully using nuclear magnetic resonance, MASS, Fourier transform infrared spectroscopy, and gel permeation chromatography technique. Thermogravimetric analysis, Fourier transform infrared spectroscopy, and scanning electron microscope techniques are employed to confirm the anchoring of Fe3O4 particles to the NORP-PHOS-CAT copolymer. Formation of nano-aggregates from NORP-PHOS-CAT copolymer is first observed in dynamic light scattering, and later, it is confirmed as nano-spheres by scanning electron microscope and transmission electron microscopy studies. Zeta-potential values of nano-spheres suggest that the cationic motifs are on the surface. The encapsulation of anionic dye methyl orange to the nanocarrier is analyzed through UV-Vis spectroscopy in aqueous medium. DNA binding nature of NORP-PHOS-CAT-Fe copolymer is confirmed through the circular dichroism measurement and UV-Vis spectroscopy. To the best of our knowledge, this is the first report where the norbornene-derived copolymers that are elegantly synthesized with both magnetic as well as cationic nature to demonstrate the effective encapsulation of dye into the nano-spheres followed by its release. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

It is demonstrated that the postfunctionalization of solid polymeric microspheres can generate fully and throughout functionalized materials, contrary to the expectation that core-shell structures are generated. The full functionalization is illustrated on the example of photochemically generated microspheres, which are subsequently transformed into polyradical systems. Given the all-organic nature of the functionalized microspheres, characterization methods with high analytical sensitivity and spatial resolution are pioneered by directly visualizing the inner chemical distribution of the postfunctionalized microspheres based on characteristic electron energy loss signals in transmission electron microscopy (TEM). Specifically, ultrasonic ultramicrotomy is combined successfully with electron energy loss spectroscopy (EELS) and electron spectroscopic imaging (ESI) during TEM. These findings open a key avenue for analyzing all-organic low-contrast soft-matter material structures, while the specifically investigated system concomitantly holds promise as an all-radical solid-state functional material., (© 2023 The Authors. Advanced Materials published by Wiley-VCH GmbH.)

ABSTRACT Tailor-made polymers containing specific chemical functionalities have ushered in a number of emerging fields in polymer science. In most of these next-generation applications the focus of the community has centered upon closed-shell macromolecules. Conversely, macromolecules containing stable radical sites have been less studied despite the promise of this evolving class of polymers. In particular, radical-containing macromolecules have shown great potential in magnetic, energy storage, and biomedical applications. Here, the progress regarding the syntheses of open-shell containing polymers are reviewed in two distinct subclasses. In the first, the syntheses of radical polymers (i.e., materials composed of non-conjugated macromolecular backbones and with open-shell units present on the polymer pendant sites) are described. In the second, polyradical (i.e., macromolecules containing stabilized radical sites either within the macromolecular backbone or those containing radical sites that are stabilized through a large degree of conjugation) synthetic schemes are presented. Thus, the state-of-the-art in open-shell macromolecular syntheses will be reported and future means by which to advance the current archetype will be discussed. By detailing the synthetic pathways possible for, and the inherent synthetic limitations of, the creation of these functional polymers, the community will be able to extend the bounds of the radical-containing macromolecular paradigm. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1875-1894 [ABSTRACT FROM AUTHOR]

In this work, multifunctional hydrogels with vivid color change and shrinking-swelling response to temperature, ion strength, and alternating magnetic field are fabricated via magnetic assembly. The hydrogels show gradual shift colors from yellowish green to green, cyan, blue, purple, and even reddish violet in response to temperature or ion strength. In the response process, the whole color modulation process is fully reversible and transferable along with a relative short response time. Especially, the magnetism and porous structure of the hybrid hydrogel enable it to be a potential carrier for hydrophobic molecules. Taking advantage of the magnetocaloric responsiveness, the dyed oil loaded hydrogel exhibits a controllable release behavior in each reversible shrinking-swelling cycle under an alternating magnetic field. This multi-responsive hydrogel can hold promise for practical engineering applications, including sensors, displays, and controlled release. [ABSTRACT FROM AUTHOR]

ABSTRACT Nonspecific interaction is a key parameter affecting the efficiency of proteins, nucleic acids or cell separation. Currently, many approaches to introduce antifouling properties to materials have been developed. Among these, surface modification with polymer brushes plays a prominent role. The aim of this study was to synthesize new magnetic microspheres grafted with poly( N,N-dimethylacrylamide) (PDMA) that resist nonspecific protein adsorption. Monodisperse macroporous poly(2-hydroxyethyl methacrylate) (PHEMA) microspheres, 4 μm in size, were synthesized by a multiple swelling polymerization method. To render the microspheres magnetic, iron oxide was precipitated inside the microsphere pores. Functional carboxyl groups, introduced by the hydrolysis of the 2-(methacryloyl)oxyethyl acetate (HEMA-Ac) comonomer, were used to react with propargylamine, followed by coupling of a chain transfer agent via an azide-alkyne click reaction. PDMA was grafted from the PHEMA microspheres using reversible addition-fragmentation chain transfer polymerization (RAFT), resulting in surfaces with more than 81 wt % PDMA attached. The successful modification of the microspheres was confirmed by XPS. The magnetic microspheres grafted with PDMA showed excellent antifouling properties as tested in bovine serum protein solutions. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1036-1043 [ABSTRACT FROM AUTHOR]

This paper proposes the development of isotactic polypropylene (iPP) nanocomposites with magnetic carbon-based hybrid fillers, which contain magnetite, by melt mixing at 190 °C. The carbon-based fillers such as carbon nanotubes (CNTs) were synthesized via chemical vapor deposition (CVD), using ferrocene as catalyst and precursor synthesis, and using silica (SiO 2 ) or thermally reduced graphene oxide (TrGO) as support, obtaining SiO 2 /CNT Magnetite and TrGO/CNT Magnetite hybrid nanostructures, respectively. Mechanical, electrical and magnetic behaviors of the iPP nanocomposites with magnetic CNTs were evaluated; their performance against iPP composites with commercial CNTs was compared. The results show that the electrical conductivity of the iPP nanocomposites is not affected by the presence of magnetite, reaching a percolation threshold similar to that obtained in iPP nanocomposites with commercial CNTs. Likewise, the presence of CNTs with magnetic particles changes the diamagnetic nature of the polymeric matrix, transforming it into a ferromagnetic composite at low filler concentrations (2 wt.%). [ABSTRACT FROM AUTHOR]

A novel magnetic Zn (II) ion-imprinted polymer was prepared by the surface ion-imprinted technique by using magnetic Fe3O4@SiO2microspheres as supporter, methacrylic acid and salicylaldoxime as monomers, ethylene glycol dimethacrylate as the crosslinker. The products were characterized by Fourier transform infrared, X-ray photoelectron spectrometer, vibrating sample magnetometer and scanning electron microscope. The adsorption experiments showed that the imprinted polymer was employed successfully in comparison with non-imprinted polymer. When the temperature was in a range of 291–297 K, the maximum adsorption was about 52.69 mg g−1with an optimal pH 6.0 for an equilibrium time of 40 min. The imprinted polymer possessed high selectivity and specific recognition towards Zn (II). The Langmuir adsorption model was more favourable than the Freundlich or the Temkin adsorption model. Thermodynamic experiment showed that the adsorption was a spontaneous and endothermic process for Zn (II). The mechanism for Zn (II) adsorption on the imprinted polymer was investigated. [ABSTRACT FROM AUTHOR]

ABSTRACT Smart superporous hydrogels (SPHs) based on dimethylaminoethyl methacrylate and acrylamide monomers with and without magnetic nanoparticles (MNPs) were synthesized via a microwave procedure. The synthesized samples were confirmed by various techniques such as Fourier transform spectroscopy, x-ray diffraction, thermogravimetric analysis, scanning electron microscopy, vibrating sample magnetometry, and transmission electron microscopy. The parameters such as pH, irradiation time, and MNPs content on the swelling behavior of products were studied. The results of swelling studies in artificial gastric and intestine media exhibited a higher swelling ratio of SPHs in lower pH, confirming smart performance of SPHs for gastroretentive drug delivery (GDD). The metronidazole (MTZ) was used as an effective antibiotic administered in peptic ulcer therapy. The in vitro release studies showed that the presence of MNPs into the hydrogel network provided the sustained release pattern for MTZ. It was concluded that our developed SPHs and MSPHs fabricated via a facile method have potential to be used in GDD. [ABSTRACT FROM AUTHOR]

Magnetic vinylphenyl boronic acid microparticles, poly(ethylene glycol dimethacrylate(EG)–vinylphenyl boronic acid(VPBA)) [ m -poly(EG–VPBA)], produced by suspension polymerization and characterized, was found to be an efficient solid polymer for Cr(VI) adsorption. The m -poly(EG–VPBA) microparticles were prepared by copolymerizing of ethylene glycol dimethylacrylate (EG) with 4-vinyl phenyl boronic acid (VPBA). The m -poly(EG–VPBA) microparticles were characterized by N 2 adsorption/desorption isotherms, electron spin resonance (ESR), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), elemental analysis, scanning electron microscope (SEM) and swelling studies. The m -poly(EG–VPBA) microparticles were used at adsorbent/Cr(VI) ion ratios. The influence of pH, Cr(VI) initial concentration, temperature of the removal process was investigated. The maximum removal of Cr(VI) was observed at pH 2. Langmuir isotherm and Dubinin–Radushkvich isotherm were found to better fit the experiment data rather than Fruendlich isotherm. The kinetics of the adsorption process of Cr(VI) on the m -poly(EG–VPBA) microparticles were investigated using the pseudo first-order, pseudo-second-order, Ritch-second-order and intraparticle diffusion models, results showed that the pseudo-second order equation model provided the best correlation with the experimental results. The thermodynamic parameters (free energy change, Δ G 0 enthalpy change, Δ H 0 ; and entropy change, Δ S 0 ) for the adsorption have been evaluated. [ABSTRACT FROM AUTHOR]

ABSTRACT Core-shell magnetic nanoparticles have received significant attention recently and are actively investigated owing to their large potential for a variety of applications. In this study, the synthesis and characterization properties of magnetite @ polyrhodanine (Fe3O4 @ PRh) core-shell nanoparticles have been investigated. To monitor the morphology, size, structure, thermal stability, and magnetic properties of nanoparticles, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetic analysis, and vibrating sample magnetometer were carried out. The results indicate that a thin film of polyrhodanine was coated on the surface of Fe3O4 nanoparticles. The coated shell of polyrhodanine can protect the Fe3O4 cores from being oxidized. Also, the results presented the crystalline, small size, and high magnetization value for the core-shell structure. [ABSTRACT FROM AUTHOR]