Flexible Janus nanofiber to acquire tuned and enhanced simultaneous magnetism-luminescence bifunctionality

A novel nanostructure of [CoFe₂O₄/PVP]//[YAG:7 % Tb³⁺/PVP] magnetic-luminescent bifunctional Janus nanofibers has been successfully fabricated via electrospinning technology using a homemade parallel spinneret. Electrospun YAG:7 % Tb³⁺ luminescent nanofibers and CoFe₂O₄ magnetic nanofibers were respectively incorporated into polyvinyl pyrrolidone (PVP) matrix and electrospun into Janus nanofibers with CoFe₂O₄ magnetic nanofibers/PVP as one strand nanofiber and YAG:7 % Tb³⁺ luminescent nanofibers/PVP as another strand nanofiber. [CoFe₂O₄/PVP]//[YAG:7 % Tb³⁺/PVP] magnetic-luminescent bifunctional Janus nanofibers possess superior magnetic and luminescent properties due to their peculiar nanostructure, and the luminescent characteristics and saturation magnetizations of the Janus nanofibers can be tuned by adding various amounts of YAG:7 % Tb³⁺ luminescent nanofibers and CoFe₂O₄ magnetic nanofibers. Compared with CoFe₂O₄/YAG:7 % Tb³⁺/PVP composite nanofibers, the magnetic-luminescent bifunctional Janus nanofibers provide higher performances due to isolating YAG:7 %Tb³⁺ luminescent nanofibers from CoFe₂O₄ magnetic nanofibers. Formation mechanism of [CoFe₂O₄/PVP]//[YAG:7 % Tb³⁺/PVP] Janus nanofibers is also presented. The design conception and construction technology are of universal significance to fabricate other bifunctional Janus nanofibers.     

Parallel spinnerets electrospinning construct and properties of electrical-luminescent bifunctional bistrand-aligned nanobundles

A structure of electrical-luminescent bifunctional bistrand-aligned nanobundles has been successfully fabricated by specially designed parallel spinnerets electrospinning technology. Eu(BA)₃phen (BA = benzoic acid, phen = 1,10-phenanthroline) and polyaniline (PANI) were respectively incorporated into polyvinyl pyrrolidone (PVP) and electrospun into bistrand-aligned nanobundles with PANI/PVP as one strand nanofiber and Eu(BA)₃phen/PVP as another strand nanofiber. The morphologies and properties of the final products were investigated in detail by scanning electron microscopy, transmission electron microscopy, fluorescence spectroscopy, Hall effect measurement system, and UV–Vis-NIR spectrophotometer. It is found that the as-prepared samples exhibit the nanostructures of bistrand-aligned nanobundles. The mean diameter for individual nanofiber of the bistrand-aligned nanobundles is 180 nm. The [PANI/PVP]//[Eu(BA)₃phen/PVP] bistrand-aligned nanobundles possess excellent electrical conduction and luminescent properties. Fluorescence emission peaks of Eu³⁺ are observed in the [PANI/PVP]//[Eu(BA)₃phen/PVP] electrical-luminescent bifunctional bistrand-aligned nanobundles and assigned to ⁵D₀ → ⁷F₀ (581 nm), ⁵D₀ → ⁷F₁ (592 nm), ⁵D₀ → ⁷F₂ (615 nm) energy levels transitions of Eu³⁺ ions, and the ⁵D₀ → ⁷F₂ hypersensitive transition at 615 nm is the predominant emission peak. The electrical conductivity reaches up to the order of 10^?3 S/cm. The electrical conductivity and luminescent intensity of the bistrand-aligned nanobundles can be tunable by adding various amounts of PANI and rare earth complex. The novel [PANI/PVP]//[Eu(BA)₃phen/PVP] electrical-luminescent bifunctional bistrand-aligned nanobundles have potential applications in display devices and nanomechanics, etc. owing to their excellent electrical conduction and fluorescence.     

Janus nanofiber: a new strategy to achieve simultaneous enhanced magnetic-photoluminescent bifunction

Magnetic-photoluminescent bifunctional Janus nanofibers have been successfully fabricated by electrospinning technology using a homemade parallel spinneret. NaYF₄:Eu³⁺ and Fe₃O₄ nanoparticles (NPs) were respectively incorporated into polyvinyl pyrrolidone (PVP) and eleactrospun into Janus nanofibers with NaYF₄:Eu³⁺/PVP as one strand nanofiber and Fe₃O₄/PVP as another strand nanofiber. The morphologies, structures, magnetic and photoluminescent properties of the as-prepared samples were investigated in detail by X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, energy dispersive spectrometry, vibrating sample magnetometry and fluorescence spectroscopy. The results show Janus nanofibers simultaneously possess superior magnetic and luminescent properties due to their special structure, and the luminescent characteristics and saturation magnetizations of the Janus nanofibers can be tuned by adding various amounts of NaYF₄:Eu³⁺ NPs and Fe₃O₄ NPs. Compared with Fe₃O₄/NaYF₄:Eu³⁺/PVP composite nanofibers, the magnetic-photoluminescent bifunctional Janus nanofibers provide better performances due to isolating NaYF₄:Eu³⁺ NPs from Fe₃O₄ NPs. The novel magnetic-photoluminescent bifunctional Janus nanofibers have potential applications in the fields of new nano-bio-label materials, drug target delivery materials and future nanodevices owing to their excellent magnetic and luminescent performance. More importantly, the design conception and construction technology are of universal significance to fabricate other bifunctional Janus nanofibers.     

Photoluminescence–electricity–magnetism trifunction simultaneously assembled into one flexible nanofiber

In order to develop new-typed multifunctional composite nanofibers, Eu(BA)₃phen/PANI/Fe₃O₄/PVP trifunctional composite nanofibers with photoluminescence, electricity and magnetism have been successfully fabricated via electrospinning technology. Polyvinyl pyrrolidone (PVP) is used as a matrix to construct composite nanofibers containing different amounts of Eu(BA)₃phen, polyaniline (PANI) and magnetite Fe₃O₄ nanoparticles (NPs). X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry, fluorescence spectroscopy and Hall effect measurement system are used to characterize the morphology and properties of the obtained composite nanofibers. The results indicate that the trifunctional composite nanofibers possess excellent luminescent, electrical conductivity and magnetic properties. Fluorescence emission peaks of Eu³⁺ are observed in the Eu(BA)₃phen/PANI/Fe₃O₄/PVP photoluminescent-electrical-magnetism trifunctional composite nanofibers and assigned to the of ⁵D₀ → ⁷F₀ (580 nm), ⁵D₀ → ⁷F₁ (593 nm) of Eu³⁺, and the ⁵D₀ → ⁷F₂ hypersensitive transition at 615 nm is the predominant emission peak. The electrical conductivity reaches up to the order of 10^?3 S/cm. The luminescent intensity, electrical conductivity and saturation magnetization of the composite nanofibers can be tunable by adding various amounts of Eu(BA)₃phen, PANI and Fe₃O₄ NPs. The multifunctional composite nanofibers are expected to possess many potential applications in areas such as electromagnetic interference shielding, microwave absorption, molecular electronics and biomedicine.     

A single flexible nanofiber to obtain simultaneous tunable color-electricity bifunctionality

For the purpose of developing new-typed multifunctional composite nanofibers, novel composite nanofibers with tunable color-electricity bifunctionality have been successfully fabricated via facile one-pot electrospinning technology. The obtained bifunctional composite nanofibers are composed of polyvinyl pyrrolidone (PVP) as the matrix, Tb(BA)₃phen and Eu(BA)₃phen (BA = benzoic acid, phen = phenanthroline) as luminescence materials and polyaniline (PANI) as conductive material. Scanning electron microscopy, energy dispersive spectrometry, fluorescence spectroscopy and Hall effect measurement system are used to characterize the morphology structure and properties of the [Tb(BA)₃phen + Eu(BA)₃phen]/PANI/PVP composite nanofibers. The results indicate that the bifunctional composite nanofibers possess excellent photo luminescence and electrical conduction. The emitting color of the luminescent composite nanofibers can be tuned by adjusting the mass ratios of Tb(BA)₃phen, Eu(BA)₃phen and PANI in a wide color range of red-yellow-green under the excitation of 297-nm single-wavelength ultraviolet light. The electrical conductivity reaches up to the order of 10^?4 S/cm. The luminescent intensity and electrical conductivity of the composite nanofibers can be tunable by adding various amounts of Tb(BA)₃phen, Eu(BA)₃phen and PANI. The bifunctional composite nanofibers are expected to possess many potential applications in areas such as color display, electromagnetic shielding, molecular electronics and biomedicine.     

Fabrication of magnetic-luminescent bifunctional composite nanofibers via facile electrospinning

Fe₃O₄/Eu(BA)₃phen/polyvinyl pyrrolidone (PVP) magnetic-luminescent bifunctional composite nanofibers have been successfully fabricated based on ferroferric oxide (Fe₃O₄) nanoparticles (NPs) and europium complexes Eu(BA)₃phen (BA = benzoic acid, phen = phenanthroline) via electrospinning technology. The as-prepared samples were characterized by X-ray diffractometry, field-emission scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, fluorescence spectroscopy and vibrating sample magnetometry. The as-prepared Fe₃O₄/Eu(BA)₃phen/PVP composite nanofibers possess good fibrous morphology, and Fe₃O₄ NPs are evenly dispersed into nanofibers. Under the excitation of 274-nm ultraviolet light, Fe₃O₄/Eu(BA)₃phen/PVP composite nanofibers exhibit red emissions of predominant peaks at 592 and 616 nm, which are respectively attributed to the ⁵D₀ → ⁷F₁ and ⁵D₀ → ⁷F₂ energy levels transitions of Eu³⁺ ions. The optimum mass percentage of Eu(BA)₃phen to PVP is 15 %. The fluorescence intensity of composite nanofibers is decreased when more Fe₃O₄ NPs were added. The saturation magnetization is increased with the increase of Fe₃O₄ NPs, indicating that the magnetism of the composite nanofibers can be tuned by adjusting Fe₃O₄ NPs content. The magnetic-luminescent bifunctional composite nanofibers are expected to apply in the fields of cell separation and biological labeling imaging, etc.     

Fabrication of aligned ferrite nanofibers by magnetic-field-assisted electrospinning coupled with oxygen plasma treatment

This paper describes a simple and effective approach to fabrication of aligned magnetic ferrite nanofibers by magnetic-field-assisted electrospinning coupled with oxygen plasma treatment. Large and flexible magnetic hybrid membranes of aligned Fe₃O₄/PVP composite nanofibers were fabricated readily by electrospinning mixtures of Fe₃O₄/PVP in a magnetic field. The PVP matrix could be removed either by calcination or by oxygen plasma treatment. Oxygen plasma treatment retained the original crystalline phase of Fe₃O₄, and large inorganic membranes of aligned ferrite nanofibers were obtained. The ferrite nanofibers showed ferromagnetic behaviors, and are promising in flexible magnetic membranes, magnetic separation, drug delivery, and magnetic sensors.     

Electrospun Fe3O4/PVP//Tb(BA)3phen/PVP magnetic–photoluminescent bifunctional bistrand aligned composite nanofibers bundles

Fe₃O₄/PVP//Tb(BA)₃phen/PVP magnetic–photoluminescent bifunctional bistrand aligned composite nanofibers bundles based on Fe₃O₄ nanoparticles (NPs) and terbium complex Tb(BA)₃phen (BA = benzoic acid) were fabricated by employing a parallel axial electrospinning setup and were characterized by X-ray diffraction, field-emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), transmission electron microscopy, fluorescence spectroscopy, and vibrating sample magnetometer. It is found that Fe₃O₄ NPs were only dispersed into one strand of the bistrand aligned composite nanofibers bundles, but no nanoparticles in the other strand. And the average diameter of the individual strand fiber was 200 ± 25 nm. The bistrand aligned composite nanofibers bundles exhibit strong green emissions under the excitation of 275 nm ultraviolet light, and the ⁵ D ₄ → ⁷ F ₅ hypersensitive transition at 545 nm was the predominant emission peak of Tb³⁺ ions. The newly obtained bifunctional nanofibers bundles exhibit excellent magnetism and high fluorescence intensity and are expected to apply in biology cell separation, magnetic resonance imaging, drug deliver, and fluorescence immunoassays/imaging.     

Coaxial nanofibers to help achieve tunable and enhanced simultaneous magnetic-luminescent bifunctionality

A new nanostructure of CoFe₂O₄@Y₂O₃:5 %Tb³⁺ magnetic-luminescent bifunctional coaxial nanofibers has been successfully fabricated via electrospinning technology using a homemade coaxial spinneret. The morphologies, structures, magnetic and luminescent properties of the final products were investigated in detail by X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry, and fluorescence spectroscopy. The results show the CoFe₂O₄@Y₂O₃:5 %Tb³⁺ magnetic-luminescent bifunctional coaxial nanofibers simultaneously possess superior magnetic and luminescent properties due to isolating Y₂O₃:5 %Tb³⁺ luminescence center from CoFe₂O₄ magnetic nanofibers. Furthermore, the luminescent intensity and color of the coaxial nanofibers can be tuned via adjusting the concentrations of rare earth ions. The bifunctional magnetic-luminescent CoFe₂O₄@Y₂O₃:5 %Tb³⁺ coaxial nanofibers have potential applications in biomedical area, such as drug-delivery systems, cell labeling and separation, enhancement for magnetic resonance imaging, and subsequent optical identification. More importantly, the design conception and construction technology are of universal significance to fabricate other bifunctional coaxial nanofibers.     

Coaxial electrospinning preparation and properties of magnetic–photoluminescent bifunctional CoFe2O4@Y2O3:Eu3+ coaxial nanofibers

CoFe₂O₄@Y₂O₃:Eu³⁺ magnetic–fluorescent bifunctional coaxial nanofibers have been successfully obtained via calcination of the [CoFe₂O₄/PVP]@[(Y(NO₃)₃ + Eu(NO₃)₃)/PVP] composite coaxial nanofibers which were fabricated by coaxial electrospinning technique. The diameter of CoFe₂O₄@Y₂O₃:5 %Eu³⁺ magnetic–fluorescent bifunctional coaxial nanofibers was 133 ± 17 nm. Strong fluorescence emission peaks of Eu³⁺ in the CoFe₂O₄@Y₂O₃:Eu³⁺ coaxial nanofibers were observed and assigned to ⁵D₀ → ⁷F₁ (588 nm), ⁵D₀ → ⁷F₁ (593 nm), ⁵D₀ → ⁷F₁ (599 nm), ⁵D₀ → ⁷F₂ (612 nm) and ⁵D₀ → ⁷F₂ (630 nm) energy levels transitions of Eu³⁺ ions, and the predominant emission peak was located at 612 nm. Compared with CoFe₂O₄/Y₂O₃:Eu³⁺ composite nanofibers, CoFe₂O₄@Y₂O₃:Eu³⁺ magnetic–fluorescent bifunctional coaxial nanofibers simultaneously provided higher magnetism and fluorescent intensity. The color, photoluminescent intensity and magnetism of the coaxial nanofibers can be tuned via adjusting the diversity and content of fluorescent compounds and the content of magnetic compounds. Formation mechanism of CoFe₂O₄@Y₂O₃:Eu³⁺ coaxial nanofibers was also presented. The bifunctional magnetic–photoluminescent CoFe₂O₄@Y₂O₃:Eu³⁺ coaxial nanofibers have potential applications in many fields due to their excellent magnetism and fluorescence.     

A new strategy to assemble enhanced magnetic–photoluminescent bifunction into a flexible nanofiber

A new type of magnetic–photoluminescent bifunctional [Fe₃O₄@Y₂O₃:Eu³⁺]/polyvinyl pyrrolidone (PVP) flexible composite nanofibers were successfully prepared via electrospinning through dispersing Fe₃O₄@Y₂O₃:Eu³⁺ core–shell structured nanoparticles (NPs) into the PVP matrix. The structure, morphology, and properties of the flexible composite nanofibers were investigated by X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), and fluorescence spectroscopy. The diameter of [Fe₃O₄@Y₂O₃:Eu³⁺]/PVP nanofibers is ca. 128.57 ± 36.72 nm. Fluorescence emission peaks of Eu³⁺ in both Fe₃O₄@Y₂O₃:Eu³⁺ NPs and [Fe₃O₄@Y₂O₃:Eu³⁺]/PVP nanofibers are observed and assigned to the energy levels transitions of ⁵D₀ → ⁷F₀ (580 nm), ⁵D₀ → ⁷F₁ (533, 586, 592, 599 nm), ⁵D₀ → ⁷F₂ (612 nm), and ⁵D₀ → ⁷F₃ (629 nm) of Eu³⁺ ions. Compared with Fe₃O₄/Y₂O₃:Eu³⁺/PVP nanofibers, [Fe₃O₄@Y₂O₃:Eu³⁺]/PVP nanofibers possess much stronger luminescence. The as-prepared [Fe₃O₄@Y₂O₃:Eu³⁺]/PVP flexible composite nanofibers simultaneously exhibit excellent magnetism and photoluminescent performance. The intensities of magnetism and luminescence of the composite nanofibers can be simultaneously tuned by adjusting the amount of Fe₃O₄@Y₂O₃:Eu³⁺ NPs introduced into the nanofibers. The high performance [Fe₃O₄@Y₂O₃:Eu³⁺]/PVP flexible composite nanofibers have potential applications in bioimaging, cell separation, and future nanomechanics.     

Removal and reuse of Ag nanoparticles by magnetic polyaniline/Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> nanofibers

For the treatment of wastewater containing Ag nanoparticles (NPs), PANI/Fe₃O₄ nanofibers were firstly prepared by a novel self-assemble. And then, the efficiency for the removal of Ag NPs from wastewater was investigated. The magnetic performance of PANI/Fe₃O₄ nanofibers could be optimized by adjusting the pH of the self-assemblied system. Under pH of 3, the as-prepared nanofibers exhibited the highest magnetism and also displayed good efficiency (>?12 mg g^?1) for the removal of Ag NPs. Importantly, the resulted product (PANI/Fe₃O₄/Ag composite) could act as a catalysis for cleaning durable pollutant, 4-nitrophenol. After 10 cycles, only slight decrease in rate constant was found, indicating excellent reusability. Those approaches provide a new way to merge the recovery of Ag NPs as pollutants and reuse of recovered Ag NPs as recyclable material for environmental remediation.     

A simple route to form magnetic chitosan nanoparticles from coaxial-electrospun composite nanofibers

Composite non-woven mats of poly(vinyl pyrrolidone) (PVP), chitosan, and Fe₃O₄ were successfully fabricated using coaxial-electrospinning technique with PVP/chitosan as the shell and PVP/Fe₃O₄ as the core. Because of the templating and confinement properties of the nanofibers, magnetic chitosan nanoparticles (MCNPs) could be spontaneously formed through molecular self-assembly when the composite fibers were dissolved on treatment with acetum solution. By changing the weight ratio of Fe₃O₄:chitosan, the size of the MCNPs could be varied. The morphology, chemical composition, and magnetic characteristics of composite particles were characterized by means of scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and vibrating sample magnetometer. Experimental results indicated that the composite particles were super-paramagnetic with sizes in the range of 15–40 nm. This facile and new synthesis route comprises a convenient strategy to generate composite particles and should be broadly applicable to a wide range of systems, serving as a platform for the facile development of novel composite materials.     

静电纺制备Fe3O4/PEK-C纳米复合膜及其吸波性能

静电纺丝技术是一种新颖、高效且简单的制备连续纳米纤维的方法,纳米复合纤维膜的优异特点赋予了纳米吸波剂新的吸波通道。本文采用静电纺丝工艺制备Fe3O4/PEK-C纳米复合纤维膜,利用SEM和TGA表征纳米复合纤维膜的微观形貌和热稳定性,用矢量网络分析仪测试样品在8.2~12.4 GHz的电磁参数与吸波性能。结果表明,Fe3O4/PEK-C纳米复合纤维膜呈现出超细纤维彼此交织构成的立体网络结构,其热稳定性、复介电常数和复磁导率均随着Fe3O4含量的增加而增加,介电损耗和磁损耗得到加强。当纳米复合纤维膜的厚度为1.8 mm时,其反射损耗在整个测试波段均处于-5 dB以下,-10 dB以下有效吸收频宽为2 GHz,频率在8.6 GHz处吸收强度达到最大值-15.4 dB。预期可作为隐身复合材料的吸波功能层。     

Electrospun magnetic poly(l-lactide) (PLLA) nanofibers by incorporating PLLA-stabilized Fe3O4 nanoparticles

Magnetic poly(l-lactide) (PLLA)/Fe₃O₄ composite nanofibers were prepared with the purpose to develop a substrate for bone regeneration. To increase the dispersibility of Fe₃O₄ nanoparticles (NPs) in the PLLA matrix, a modified chemical co-precipitation method was applied to synthesize Fe₃O₄ NPs in the presence of PLLA. Trifluoroethanol (TFE) was used as the co-solvent for all the reagents, including Fe(II) and Fe(III) salts, sodium hydroxide, and PLLA. The co-precipitated Fe₃O₄ NPs were surface-coated with PLLA and demonstrated good dispersibility in a PLLA/TFE solution. The composite nanofiber electrospun from the solution displayed a homogeneous distribution of Fe₃O₄ NPs along the fibers using various contents of Fe₃O₄ NPs. X-ray diffractometer (XRD) and vibration sample magnetization (VSM) analysis confirmed that the co-precipitation process had minor adverse effects on the crystal structure and saturation magnetization (Ms) of Fe₃O₄ NPs. The resulting PLLA/Fe₃O₄ composite nanofibers showed paramagnetic properties with Ms directly related to the Fe₃O₄ NP concentration. The cytotoxicity of the magnetic composite nanofibers was determined using in vitro culture of osteoblasts (MC3T3-E1) in extracts and co-culture on nanofibrous matrixes. The PLLA/Fe₃O₄ composite nanofibers did not show significant cytotoxicity in comparison with pure PLLA nanofibers. On the contrary, they demonstrated enhanced effects on cell attachment and proliferation with Fe₃O₄ NP incorporation. The results suggested that this modified chemical co-precipitation method might be a universal way to produce magnetic biodegradable polyester substrates containing well-dispersed Fe₃O₄ NPs. This new strategy opens an opportunity to fabricate various kinds of magnetic polymeric substrates for bone tissue regeneration.     

A single nanobelt to achieve simultaneous photoluminescence–electricity–magnetism trifunction

In order to develop new-typed multifunctional composite nanobelts, polymethyl methacrylate (PMMA) is used as the matrix to construct composite nanobelts containing different amounts of Eu(BA)₃phen(BA = benzoic acid, phen = phenanthroline), polyaniline (PANI) and Fe₃O₄ nanoparticles (NPs), and Eu(BA)₃phen/PANI/Fe₃O₄/PMMA trifunctional composite nanobelts with simultaneous photoluminescence, electricity and magnetism have been successfully fabricated via electrospinning technology. The morphology and properties of the obtained composite nanobelts were characterized by X-ray diffractometry, scanning electron microscopy, vibrating sample magnetometry, fluorescence spectroscopy and Hall effect measurement system. The results indicate that the trifunctional composite nanobelts simultaneously possess excellent photoluminescence, electrical conduction and magnetic properties. Fluorescence emission peaks of Eu³⁺ ions in the composite nanobelts are observed and assigned to the energy levels transitions of ⁵D₀ → ⁷F₀ (580 nm), ⁵D₀ → ⁷F₁ (593 nm) and ⁵D₀ → ⁷F₂ (615 nm) of Eu³⁺ ions, and the ⁵D₀ → ⁷F₂ hypersensitive transition at 615 nm is the predominant emission peak. The electrical conductivity reaches up to the order of 10^?3 S/cm. Furthermore, the luminescent intensity, electrical conductivity and saturation magnetization of the composite nanobelts can be tunable by adjusting amounts of Eu(BA)₃phen, PANI and Fe₃O₄ NPs. The formation mechanism of the composite nanobelts is also proposed. The obtained photoluminescence–electricity–magnetism trifunctional composite nanobelts have potential applications in many areas such as electromagnetic interference shielding, microwave absorption, molecular electronics, biomedicine and future nanomechanics. More importantly, the design concept and construct technique are of universal significance to fabricate other trifunctional naonobelts.     

Electromagnetic and microwave absorbing properties of magnetite nanoparticles decorated carbon nanotubes/polyaniline multiphase heterostructures

Magnetite nanoparticles decorated CNTs/PANI multiphase heterostructures were prepared by polymerization of aniline monomer and an additional process of the coprecipitation of Fe²⁺ and Fe³⁺. Scanning electron microscopy and transmission electron microscopy observation indicated that the monodispersed magnetite nanoparticles were uniformly decorated on the surface of CNTs/PANI. The formation of magnetite nanoparticles on CNTs/PANI was mainly through a preferentially position-selective precipitation process. More interestingly, a portion of Fe₃O₄ nanoparticles was found to form core–shell structures with PANI. The effects of different additional amounts of NH₂Fe(SO₄)₂·6H₂O reactant on the magnetic properties and microwave absorbing performances of CNTs/PANI/Fe₃O₄ heterostructures were investigated. The CNTs/PANI/Fe₃O₄ multiphase heterostructures were proved to be superparamagnetic. The microwave absorption measurement showed that the CNTs/PANI/Fe₃O₄ samples under 1.5 g of NH₂Fe(SO₄)₂·6H₂O condition exhibited much more effective absorption performance. These results suggested the novel CNTs/PANI/Fe₃O₄ multiphase heterostructures with PANI as the second phase may be potential candidate for microwave absorption systems.     

Fabrication and microwave absorption performances of hollow-structure Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>/PANI microspheres

The hollow polyaniline (PANI) microspheres were prepared by controlling the mass ratio of the aniline to polystyrene (PS) via a template method, and Fe₃O₄/PANI composite microspheres have been fabricated by blending the hollow PANI microspheres with Fe₃O₄ magnetic particles. The effects of the mass ratio of aniline/PS on the microwave absorption performances of Fe₃O₄/PANI microspheres were investigated. It was found that the value of minimum reflection loss (RL_min) of the microspheres were respectively ?14.06, ?22.34 and ?24.3 dB, corresponding to the mass ratio of aniline/PS of 1:1.5, 1:3, and 1:6. In addition, when the mass ratio of aniline/PS was 1:6, with the thickness of 1.5 and 2.0 mm, the bandwidth below ?10dB were respectively 2.48 GHz (15.52–18 GHz) and 4.64 GHz (11.04–15.68 GHz), indicating that the Fe₃O₄/PANI microspheres could be a potential electromagnetic wave absorbing material in X (8–12 GHz) and Ku (12–18 GHz) bands.     

Synthesis and ferrimagnetic properties of novel Sm-substituted LiNi ferrite–polyaniline nanocomposite

Polyaniline (PANI)–LiNi_0.5Sm_0.08Fe_1.92O₄ nanocomposite was synthesized by an in situ polymerization of aniline in the presence of LiNi_0.5Sm_0.08Fe_1.92O₄ ferrite. The products were characterized by powder X-ray diffractometer (XRD), Fourier transform infrared (FTIR) and UV–visible absorption spectrometer, thermogravimetric analyser (TGA), atomic force microscope (AFM) and vibrating sample magnetometer (VSM). The results of XRD, FTIR and UV–visible spectra confirmed the formation of PANI–LiNi_0.5Sm_0.08Fe_1.92O₄ composite. AFM study showed that ferrite particles had an effect on the morphology of the composite. TGA revealed that the incorporation of ferrite improved the thermal stability of PANI. The nanocomposite under applied magnetic field exhibited the hysteresis loops of ferrimagnetic nature at room temperature. The bonding interaction between ferrite and PANI in the nanocomposite had been studied.     

Preparation and photoluminescence properties of electrospun nanofibers containing PMO-PPV and Eu(ODBM)3phen

This communication explores a facile approach for fabricating nanofibers containing luminescent conjugated polymer, poly(2-methoxy-5-octoxy)-1,4-phenylene vinylene)-alt-1,4-(phenylene vinylene) (PMO-PPV), and rare earth complex, Eu(ODBM)₃phen (ODBM: 4-n-Octyloxydibenzoylmethanato; phen: 1,10-phenanthroline) via an electrospinning technique. The morphology and photoluminescent properties of the electrospun fibers were characterized by scanning electron microscopy, fluorescence spectrophotometer and UV optical microscopy. The electrospun fibers with diameters ranging from 70 nm to 200 nm as well as parallel orientation show strong green and red photoluminescence. This is the first but important approach towards novel applications of luminescent conjugated polymers and rare earth complex nanofibers. This kind of eletrospun nanofiber is a promising candidate for optical and electrical nanomaterials.