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1.
The manufacturing of pure polyacrylonitrile (PAN) fibers and magnetic PAN/Fe3O4 nanocomposite fibers is explored by an electrospinning process. A uniform, bead-free fiber production process is developed by optimizing electrospinning conditions: polymer concentration, applied electric voltage, feedrate, and distance between needle tip to collector. The experiments demonstrate that slight changes in operating parameters may result in significant variations in the fiber morphology. The fiber formation mechanism for both pure PAN and the Fe3O4 nanoparticles suspended in PAN solutions is explained from the rheologial behavior of the solution. The nanocomposite fibers were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectrophotometer, and X-ray diffraction (XRD). FT-IR and XRD results indicate that the introduction of Fe3O4 nanoparticles into the polymer matrix has a significant effect on the crystallinity of PAN and a strong interaction between PAN and Fe3O4 nanoparticles. The magnetic properties of the nanoparticles in the polymer nanocomposite fibers are different from those of the dried as-received nanoparticles. 相似文献
2.
Ying Yang Zhen Guo Huan Zhang Daqing Huang Jialin Gu Zhenghong Huang Feiyu Kang T. Alan Hatton Gregory C. Rutledge 《应用聚合物科学杂志》2013,127(6):4288-4295
Electrospun polyacrylonitrile (PAN)‐based carbon composite fibers embedded with magnetic nanoparticles have been developed as materials for electromagnetic wave absorption. The nanocomposite fibers were prepared by electrospinning from a dispersion of magnetite (Fe3O4) nanoparticles stabilized by L ‐glutamic acid in a solution of PAN and N, N‐dimethyl formamide. The Fe3O4‐embedded PAN nanofibers were stabilized at 270°C in air and carbonized at 800°C in nitrogen. The Fe3O4 nanoparticles were crystalline with a particle size of about 7 nm, most of which was reduced to Fe3C with agglomerates of up to 50 nm diameter in the carbon fibers. The carbon morphology was mostly disordered, but exhibited a layered graphitic structure in the vicinity of the nanoparticles. The carbon composite fiber exhibited ferromagnetic behavior, and the induced magnetic saturation per unit mass of fibers increased with increasing Fe3O4 content in the precursor. The complex relative dielectric permittivity was tuned by adjusting the amount of Fe3O4 in the carbon fiber precursor. With increasing Fe3O4 content, good electromagnetic wave absorption characteristics were observed below 6 GHz, even for samples with fiber loadings as low as 5 wt %. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
3.
Feng-Yi Chou Chao-Ming Shih Meng-Chao Tsai Wen-Yen Chiu Shingjiang Jessie Lue 《Polymer》2012,53(14):2839-2846
This paper reports a novel method to synthesize magnetic, stimuli-sensitive latex nanoparticles made with magnetite/poly(N-isopropylacrylamide-co-acrylic acid) (Fe3O4/P(NIPAAm-co-AAc)). To form a stabilized suspended core, iron oxide (Fe3O4) was functionalized with AAc such that further polymerization with NIPAAm and AAc monomers could occur. The P(NIPAAm-co-AAc) shell layer exhibited thermosensitive properties. The inclusion of Fe3O4 into the latex nanoparticles was confirmed using transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction spectroscopy, thermogravimetric analyzer (TGA), and superconducting quantum interference device magnetometer. The NIP–(AAc2.6–Fe) latex nanoparticles contained 2.25% Fe3O4 (by weight), as determined by TGA analysis. The particle diameters measured approximately 160–240 nm with a lower critical solution temperature of 35 °C. These novel magnetic stimuli-responsive latex nanoparticles have potential applications in numerous fields, such as catalyst supports, protein immobilization, cancer therapy, target drug delivery systems, and other biomedical applications. 相似文献
4.
《Ceramics International》2022,48(11):15105-15115
The performance of radio frequency identification (RFID) tags deteriorates in transmitting/receiving characteristics when the tags are mounted on conductive substances such as metals due to the interference from the metal reflected electromagnetic waves. In this work, the manganese-doped magnetite (MnXFe3?XO4 (0 ≤ X ≤ 1)) nanoparticles with different manganese contents are synthesized by the one-pot sol-gel method for the application of microwave absorber. The effects of Mn doping on the morphology, microstructure, dielectric and magnetic properties, and microwave absorption ability of MnXFe3?XO4 nanoparticles are investigated. The saturation magnetization and dielectric and magnetic losses of MnXFe3?XO4 nanoparticles enhance as the Mn doping increases, and achieve the maximum when X = 0.50, and decrease as the Mn doping further continues to augment. At the optimized value of X = 0.50, the reflection and transmission losses are measured to be 17.51 and 3.88 dB, respectively. Furthermore, the nanoparticles are mixed with polytetrafluoroethylene powder and hot-pressed into a composite mat to demonstrate its application as microwave absorber. When the composite mat is inserted between the RFID tag and metal surface, the RFID tag recovers the read count by 86%, which is due to the high absorption ability (80.77%) of the composite mat. Therefore, the composition tunable MnXFe3?XO4 nanoparticles can be a potential candidate for the application of microwave absorber in wireless communication and electronic industries. 相似文献
5.
《Carbon》2015
Fe3O4 nanoparticles encapsulated in porous carbon fibers (Fe3O4@PCFs) as anode materials in lithium ion batteries are fabricated by a facile single-nozzle electrospinning technique followed by heat treatment. A mixed solution of polyacrylonitrile (PAN) and polystyrene (PS) containing Fe3O4 nanoparticles is utilized to prepare hybrid precursor fibers of Fe3O4@PS/PAN. The resulted porous Fe3O4/carbon hybrid fibers composed of compact carbon shell and Fe3O4-embeded honeycomb-like carbon core are formed due to the thermal decomposition of PS and PAN. The Fe3O4@PCF composite demonstrates an initial reversible capacity of 1015 mAh g−1 with 84.4% capacity retention after 80 cycles at a current density of 0.2 A g−1. This electrode also exhibits superior rate capability with current density increasing from 0.1 to 2.0 A g−1, and capacity retention of 91% after 200 cycles at 2.0 A g−1. The exceptionally high performances are attributed to the high electric conductivity and structural stability of the porous carbon fibers with unique structure, which not only buffers the volume change of Fe3O4 with the internal space, but also acts as high-efficient transport pathways for ions and electrons. Furthermore, the compact carbon shell can promote the formation of stable solid electrolyte interphase on the fiber surface. 相似文献
6.
Facile fabrication of nanocomposite microspheres with polymer cores and magnetic shells by Pickering suspension polymerization 总被引:3,自引:0,他引:3
Chaoyang Wang Chengjin Zhang Yu Li Yunhua Chen Zhen Tong 《Reactive and Functional Polymers》2009,69(10):750-754
Pickering suspension polymerization was used to prepare magnetic polymer microspheres that have polymer cores enveloped by shells of magnetic nanoparticles. Styrene was emulsified in an aqueous dispersion of Fe3O4 nanoparticles using a high shear. The resultant Pickering oil-in-water (o/w) emulsion stabilized solely by magnetic nanoparticles was easily polymerized at 70 °C without stirring. Fe3O4 nanoparticles act as effective stabilizers during polymerization and as building blocks for creating the organic–inorganic hybrid nanocomposite after polymerization. The fabricated magnetic nanocomposites were characterized by FTIR, XRD, TGA, DSC, GPC, XPS and SEM. The structures of the polymer core and the nanoparticle shell were analyzed. We investigated the effects on the products of the weight of Fe3O4 nanoparticles used to stabilize the original Pickering emulsions. Pickering suspension polymerization provides a new route for the synthesis of a variety of hybrid nanocomposite microspheres with supracolloidal structures. 相似文献
7.
A new kind of magnetic rubber was prepared by doping Fe3O4 nanoparticles into nature rubber matrix, which was characterized by the scanning electron microscopy and X-ray spectroscopy.
They showed that the Fe3O4 nanoparticles were well dispersed in rubber matrix. Furthermore, the mechanical and magnetic properties of the magnetic rubber
were investigated, indicating the improvement of tensile strength from 13.9 to 15.8 MPa and high saturation magnetization
(16.7 emu/g) compared with the nature rubber. What’ more, the loss factor of magnetic rubber treated by an external homogenous
magnetic field (1.5 T) was improved from 0.07 to 0.15 compared with magnetic rubber without treating by the magnetic field.
The result is attributed that after applying a magnetic field, magnetic nanoparticles on the rubber matrix are magnetized;
meanwhile, magnetic dipole moments are induced, which causes magnetic field and can absorb shock energy. 相似文献
8.
Jixiao WANG Rui LIU Xiaoyan ZHANG Zhibin ZHOU Zhi WANG Shichang WANG 《Frontiers of Chemical Engineering in China》2008,2(3):231-235
A facile route to prepare Fe3O4/polypyrrole (PPY) core-shell magnetic nanoparticles was developed. Fe3O4 nanoparticles were first prepared by a chemical co-precipitation method, and then Fe3O4/PPY coreshell magnetic composite nanoparticles were prepared by in-situ polymerization of pyrrole in the presence of Fe3O4 nanoparticles. The obtained nanoparticles were characterized by scanning electronic microscopy (SEM), transmission electronic
microscopy (TEM) and laser particle size analyzer. The images indicate that the size of Fe3O4 particles is about 10 nanometers, and the particles are completely covered by PPY. The Fe3O4/PPY core-shell magnetic composite nanoparticles are about 100 nanometers and there are several Fe3O4 particles in one composite nanoparticle. The yield of the composite nanoparticles was about 50%. The sedimentation behavior
of Fe3O4/PPY core-shell magnetic nanoparticles in electrolyte and soluble polymer solutions was characterized. The experimental results
indicate that the sedimentation of particles can be controlled by adjusting electrolyte concentration, solvable polymers and
by applying a foreign field. This result is useful in preparing gradient materials and improving the stability of suspensions. 相似文献
9.
Feige Guo Qiuyu Zhang Hepeng Zhang Baoliang Zhang Junwei Gu 《Journal of Polymer Research》2011,18(4):745-751
In this work, controlled radical polymerization based on 1, 1-diphenylethylene (DPE method) was used to prepare magnetic composite
microspheres. By this method, Fe3O4/P (St-MA) magnetic composite microspheres were prepared via copolymerization of styrene (St) and maleic anhydride (MA) using
DPE as radical control agent in the presence of Fe3O4 nanoparticles. The structure and properties of the magnetic composite microspheres obtained were characterized by IR, 1H-NMR, SEC-MALLS, TEM, TGA, VSM, DLS and other instruments. It was found that the DPE method allows the controlled preparation
of magnetic composite microspheres, and Fe3O4/ P(St-MA) microspheres possess perfect sphere-shaped morphology, homogeneous particle size, carboxylic surface, superparamagnetism
with a saturation magnetization of 14.704 emu/g, and magnetic content with a value of 25%. 相似文献
10.
Synergistic effect of carbon nanofiber decorated with iron oxide in enhancing properties of styrene butadiene rubber nanocomposites
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Sung Ho Song 《应用聚合物科学杂志》2017,134(40)
Elastomer nanocomposites reinforced with carbon nanofiber (CNF) decorated with metal nanoparticles exhibit excellent thermal, mechanical, and magnetic properties with low volume fraction of the reinforcement. Generally, metal nanoparticles are used to modify the surface of CNF, to improve their dispersion and contact resistance in the polymer matrix. In this study, Fe2O3 metal nanoparticles were decorated on CNF by electrostatic attraction via a green and facile solution‐based method. Interestingly, the CNF decorated with Fe2O3 (CNF‐Fe2O3)/elastomer improved both the tensile strength and the fatigue property of plain CNF/elastomer by as much as 57.2% and 27.2%, respectively. Moreover, the CNF‐Fe2O3/elastomer exhibited superior thermal conductivity, a twofold enhancement compared with carbon fibers. The elastomer nanocomposites consisting of CNF‐Fe2O3 also exhibited enhanced magnetic properties due to synergies between the Fe2O3 nanoparticles and the CNF. The elastomer nanocomposites prepared with CNF‐Fe2O3 will open significant new opportunities for preparing advanced elastomer nanocomposites for future engineering applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45376. 相似文献
11.
Nanocomposites of magnetic nanoparticles and polymer matrices combine the properties of their components, and as such are good examples of functional nanomaterials with excellent application potential. Against this background, experimental and theoretical studies of such composites are of great interest. In this study we aim to provide insight into the static and dynamic magnetic response, as well as the dielectric response, of magnetic nanocomposites subjected to external magnetic and electric fields. We directly compare the behavior of polyurethane films doped with superparamagnetic Fe3O4, and blocked ferromagnetic CoFe2O4 nanoparticles. While a reversible, Langevin magnetization curve is observed for Fe3O4@PU films, hysteretic magnetic behavior is found in case of CoFe2O4@PU films. The hysteresis observed for CoFe2O4 nanoparticles can be explained by interactions at the interface between particles and polymer matrix in conjunction with its ferromagnetic nature. The results of dielectric spectroscopy experiments revealed different effects of Fe3O4 and CoFe2O4 nanoparticles on polymer dynamics. 相似文献
12.
Emine Hilal Mert Hüseyin Yıldırım Ahmet Talha Üzümcü Hüseyin Kavas 《Reactive and Functional Polymers》2013,73(1):175-181
Magnetic macroporous polymer monoliths have been prepared using styrene/divinylbenzene (S/DVB) high internal phase emulsions (HIPEs) as templates. Humic acid surface modified iron oxide magnetic nanoparticles (Fe3O4@HA) have been used to prepare magnetic emulsion templates. The effect of magnetic particle concentration has been investigated by changing the ratio of Fe3O4@HA nanoparticles in the continuous phase. Highly macroporous polymers with magnetic response were obtained by the removal of the internal phase after the curing of emulsions at 80 °C. Fe3O4@HA particles were characterized by XRD and FTIR. The porosity, pore morphology and magnetic properties of the macroporous polymers were characterized as a function of the Fe3O4@HA concentration by scanning electron microscopy (SEM), Brunauer–Emmet–Teller (BET) molecular adsorption method and vibrating sample magnetometry (VSM), respectively. BET and VSM measurements demonstrated that the specific surface area and the saturation magnetization of the polymer monoliths were changed according to the Fe3O4@HA concentration between 8.77–35.08 m2 g?1 and 0.63–11.79 emu g?1, respectively. Resulting magnetic monoliths were tested on the adsorption of Hg(II) and atomic absorption spectroscopy (AAS) was used to calculate the adsorption capacities. The maximum adsorption capacity of the magnetic monoliths was calculated to be 20.44 mmol g?1 at pH 4. 相似文献
13.
Chong Gu Changqing Guo Xichao Dong Zhiming Hu Pengfei Wu Zhiming Su Yingxi Lu Binbin Xu Zhaoju Yu Anhua Liu 《Journal of the American Ceramic Society》2019,102(12):7098-7107
In this work, novel core-shell structured Fe3Si@C/SiC/Fe3O4/SiO2 nanoparticles were fabricated via a polymer-derived ceramic approach, starting from sol-like polycarbosilane-encapsulated polynuclear carbonyl iron nanoparticles and with pitch as an isolator to avoid aggregation during polymer-to-ceramic transformation. Elemental analysis, X-ray photoelectron spectroscopy, X-ray diffraction, transmission electron microscope, vibrating sample magnetometer and vector network analyzer were employed to investigate the composition, nano/microstructure, morphology, and dielectric/magnetic properties. The results show that the size of obtained Fe3Si@C/SiC/Fe3O4/SiO2 nanoparticles is in the range of 2-200 nm. And the unique core-shell structure with the hetero-interface combined with simultaneous dielectric and magnetic loss endow Fe3Si@C/SiC/Fe3O4/SiO2 nanoparticles outstanding electromagnetic (EM) wave absorbing performance. With a sample thickness of 4.5 mm, the minimum reflection coefficient (RC) of the composites Fe3Si@C/SiC/Fe3O4/SiO2 mixed with paraffin wax reaches −44.7 dB, indicating that more than 99.99% EM waves can be attenuated by the composites. By adjusting the sample thicknesses, the effective bandwidth (the bandwidth of RC values lower than −10 dB) amounts 9.5 GHz (from 2.5 to 12.0 GHz), covering the whole C and X bands. 相似文献
14.
Fabrication,characterization, and properties of poly(ethylene‐co‐vinyl acetate)/magnetite nanocomposites
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M. T. Ramesan 《应用聚合物科学杂志》2014,131(7)
Poly(ethylene‐co‐vinyl acetate) (EVA)/magnetite (Fe3O4) nanocomposite was prepared with different loading of Fe3O4 nanoparticles. The mixing and compounding were carried out on a two‐roll mixing mill and the sheets were prepared in a compression‐molding machine. The effect of loading of nanoparticles in EVA was investigated thoroughly by different characterization technique such as transmission electron microscopy (TEM), X‐ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), limiting oxygen index (LOI), and technological properties. TEM analysis showed the uniform dispersion of filler in the polymer matrix and the dispersion of filler decreased with increase in filler content. XRD of the nanocomposite revealed the more ordered structure of the polymer chain. An appreciable increase in glass transition temperature was observed owing to the restricted mobility of Fe3O4‐filled EVA nanocomposite. TGA and flame resistance studies indicated that the composites attain better thermal and flame resistance than EVA owing to the interaction of filler and polymer segments. Mechanical properties such as tensile strength, tear resistance, and modulus were increased for composites up to 7 phr of filler, which is presumably owing to aggregation of Fe3O4 nanoparticle at higher loading. The presence of Fe3O4 nanoparticles in the polymer matrix reduced the elongation at break and impact strength while improved hardness of the composite than unfilled EVA. The change in technological properties had been correlated with the variation of polymer–filler interaction estimated from the swelling behavior. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40116. 相似文献
15.
M. A. Ramazanov F. V. Hajiyeva A. M. Maharramov Luca Di Palma Diana Sannino Makoto Takafuji 《Polymer-Plastics Technology and Engineering》2018,57(5):449-458
In this study, we report about the preparation of magnetic polymer nanocomposites on the basis of isotactic polypropylene and magnetite Fe3O4 nanoparticles. The structure and composition of polymer nanocomposite materials have been studied by scanning electron microscopy, atomic force microscopy, and X-ray dispersive analysis. The magnetic properties of polymer nanocomposites based on PP+Fe3O4have been investigated. It is found that not significant adhesion and agglomeration of nanoparticles occur, by increasing the nanoparticle content in polymer matrix up to 40%, and therefore they act as single-domain nanoparticles. The samples of nanocomposites based on PP+Fe3O4, with up to 40% content of Fe3O4, exhibit superparamagnetic properties. It was also found out that the magnetic polymer nanocomposite material based on PP+Fe3O4 is able to absorb ultrahigh frequency electromagnetic waves in the frequencies range from 0.1 to 30?GHz. The increase in Fe3O4 concentration from 5 to 40% at the 400?µm thicknesses of the films leads to an increase in absorption of electromagnetic waves of high frequency from 15 to 22.7%. 相似文献
16.
《Ceramics International》2021,47(23):32756-32765
A novel design of antibacterial and magnetic halloysite nanotubes loaded with Ag and Fe3O4 was reported. In detail, magnetic nanoparticles (Fe3O4) were immobilized on the surface of halloysite nanotubes (HNTs) via electrostatic adsorption (termed as HNTs/Fe3O4). The magnetic HNTs/Fe3O4 was then modified by polydopamine to in-situ grow Ag nanoparticles by a redox reaction, forming a composite nanostructure of HNTs/Fe3O4@Ag. The HNTs/Fe3O4@Ag was incorporated into poly-l-lactic acid (PLLA) scaffold fabricated via selective laser sintering, with the intent to endow the scaffold with robust antibacterial function and favorable cell activity. The results showed that the released Ag+ from the scaffold significantly against E. coli activity, with bacterial inhibition rate above 99%. Moreover, ion release behavior showed a scaffold enable to sustain release Ag+ over 28 days. Furthermore, Fe3O4 nanoparticles constructed magnetic microenvironment greatly enhanced cell activity and promoted cell proliferation. In addition, tensile strength of the scaffold increased by 52.9% compared with PLLA scaffold. These positive results suggested that the HNTs/Fe3O4@Ag nanostructure possessed potential in facilitating bone repair. 相似文献
17.
The formation of Fe3O4 nanoparticles by hydrothermal process has been studied. X‐ray Diffraction measurements were carried out to distinguish between the phases formed during the synthesis. Using the synthesized Fe3O4 nanoparticles, poly(vinyledene fluoride)‐Fe3O4 composite films were prepared by spin coating method. Scanning electron microscopy of the composite films showed the presence of Fe3O4 nanoparticles in the form of aggregates on the surface and inside of the porous polymer matrix. Differential Scanning calorimetry revealed that the crystallinity of PVDF decreased with the addition of Fe3O4. The conductitivity of the composite films was strongly influenced by the Fe3O4 content; conductivity increased with increase in Fe3O4 content. Vibration sample magnetometry results revealed the ferromagnetic behavior of the synthesized iron oxide nanoparticles with a Ms value of 74.50 emu/g. Also the presence of Fe3O4 nanoparticles rendered the composite films magnetic. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
18.
Vitalii Serdiuk Oleh Shevchuk Natalya Bukartyk Tetiana Kovalenko Anatolii Borysiuk Viktor Tokarev 《应用聚合物科学杂志》2021,138(36):50928
Magnetite nanoparticles (Fe3O4 NPs) with peroxide-containing polymer shell have been synthesized using the method of coprecipitation from the mixture solutions of Fe (II) and Fe (III) salts in the presence of peroxide-containing copolymer (PCC). Polymer shell presence has been proved by elemental and complex thermal analysis. Synthesized Fe3O4 NPs possess superparamagnetic properties. Their specific saturation magnetization decreases gradually from 65 to 54 A·m2·kg−1 with increasing PCC concentration owing to the surface spin pinning effect caused by a polymer shell. The average sizes of Fe3O4 NPs estimated from the data of XRD analysis and magnetic measurements are in the range of 9–12 nm. The NP sizes determined by the DLS method lie in the range of 150–270 nm; this result is significantly larger than the sizes estimated by the two aforementioned methods evidencing a tendency for Fe3O4 NPs toward self-association. Cross-linked composite films based on polyvinyl alcohol have been obtained via radical curing initiated by the PCC shell of nanoparticles. The resulting composite films are magnetically sensitive films with rather high physico-mechanical properties (tensile strength reaches 48–67 MPa and relative elongation – 4%–21% depending on cross-linking degree), a priori non-toxic and biocompatible, which makes them promising materials for various applications. 相似文献
19.
Synthesis,characterization, and properties of cashew gum graft poly(acrylamide)/magnetite nanocomposites
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Graft copolymer nanocomposites based on cashew gum and poly(acrylamide) with different concentrations of nano‐iron‐oxide particles (Fe3O4) have been prepared by an in situ polymerization method. The characterization of graft copolymer composite was carried out by FTIR, UV, XRD, SEM, DSC, and TGA, electrical conductivity, and magnetic property [vibrational sample magnetometer (VSM)] measurements. The shift in the spectrum of UV and FTIR peaks shows the intermolecular interaction between metal oxide nanoparticles and the graft copolymer system. The spherically shaped particles observed from the SEM images clearly indicating the uniform dispersion of nanoparticles within the graft copolymer chain. The XRD studies revealed that the amorphous nature of the graft copolymer decreases by the addition of Fe3O4 nanoparticles. The glass transition temperature studied from DSC increases with increase in concentration of metal oxide nanoparticles. Thermal stability of composite was higher than the pure graft copolymer and thermal stability increases with increase in content of nanoparticles. Electrical properties such as AC conductivity and dielectric properties of the composites increased with increase in concentration of metal oxide nanoparticles. The magnetic property of graft copolymer nanocomposites shows ferromagnetic and supermagnetism and the saturation of magnetism linearly increased with increasing the Fe3O4 content in the polymer composite. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43496. 相似文献
20.
《Carbon》2014
We describe a novel approach for coupling pristine graphene with superparamagnetic iron oxide nanoparticles to create dispersed, magnetically responsive hybrids. The magnetic iron oxide (Fe3O4) nanoparticles are synthesized by a co-precipitation method using ferric (Fe3+) and ferrous (Fe2+) salts and then grafted with polyvinylpyrrolidone (PVP). These PVP-grafted Fe3O4 nanoparticles are then used to stabilize colloidal graphene in water. The PVP branches non-covalently attach to the surface of the pristine graphene sheets without functionalization or defect creation. These Fe3O4–graphene hybrids are stable against aggregation and are highly responsive to external magnetic fields. These hybrids can be freeze-dried to a powder or magnetically separated from solution and still easily redisperse while retaining magnetic functionality. At all stages of synthesis, the Fe3O4–graphene hybrids display no coercivity after being brought to magnetic saturation, confirming superparamagnetic properties. Microscopy and light scattering data confirm the presence of pristine graphene sheets decorated with Fe3O4 nanoparticles. These materials show promise for multifunctional polymer composites as well as biomedical applications and environmental remediation. 相似文献