scholarly journals Origin of Magnetically Induced Optical Transmission of Magnetic Nanocomposite Films

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2533
Author(s):  
Qiushu Zhang ◽  
Bei Peng ◽  
Jintao Xu ◽  
Mengqi Chu
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Film Thickness ◽  
Optical Transmission ◽  
Light Transmission ◽  
Composite Films ◽  
Optical Transmittance ◽  
Nanocomposite Films ◽  
Magnetic Composite ◽  
Particle Movement

Herein, we present an investigation on the origin of the magnetically induced optical transmission of composite films comprised of polydimethylsiloxane and magnetic nanofillers via experiment and simulation. Structured and unstructured films were used in the study, which were fabricated with and without magnetic fields, respectively. Altered optical transmittance was observed from both types of films when they were subjected to an external magnetic field. Numerical analyses were performed to investigate the effect of the particle movement under magnetic field and the film magnetostriction on the film optical transmittance. The simulation results show that the changed light transmission under magnetic field is mainly due to a variation in the film thickness resulting from the film magnetostriction. The ellipsometric analysis results confirm the altered film thickness in response to the external magnetic field, and the measurements of the film magnetostrictive stresses validate that there is magnetostriction in the magnetic composite films. Additionally, it is indicated that there might be some relationship between the magnetically induced optical transmission and the film magnetostrictive stress under certain conditions.

scholarly journals Self-standing magnetic composite nanosheets prepared in the presence of an external magnetic field: Characterization and potential for medical applications

2020 ◽  
pp. 174751982095860
Author(s):  
Mina Sakuragi ◽  
Yoshikazu Takahashi ◽  
Keito Ehara ◽  
Katsuki Kusakabe
Keyword(s):  
Magnetic Field ◽  
Thermal Decomposition ◽  
External Magnetic Field ◽  
Decomposition Method ◽  
Sol Gel ◽  
Magnetic Composite ◽  
Magnetic Response ◽  
Gel Method ◽  
Sol Gel Method ◽  
Thermal Decomposition Method

The aim of this study is to develop self-standing, ultrathin film, nanosheets with high magnetic response for use in a medical device that can be migrated to a target location in the body by using an external magnetic field. First, iron oxide nanoparticles are synthesized by either the sol-gel method or thermal decomposition. The resulting magnetic properties of the nanoparticles show that the thermal decomposition method provides a greater saturation magnetization value than the sol-gel method. Next, the nanoparticles obtained by the thermal decomposition method are embedded into nanosheets of poly(L-lactide) at varying concentrations. Embedding of the nanoparticles in the composite nanosheets is achieved by the application of an external magnetic field. The composite nanosheets are then characterized. The thickness of the nanosheet increases, and the nanoparticles are well dispersed, with an increase in poly (L-lactide) concentration. The NP-embedded nanosheets are imaged by transmission electron microscopy, which reveals thin, long aggregates aligned in collinear line features. X-ray diffraction results indicate that the magnetic hard axis of the nanoparticles in the nanosheets is aligned in parallel to the plane of the nanosheet by magnetic field application during nanosheet preparation. In addition, the nanosheets at high poly (L-lactide) concentrations that had been subjected to a magnetic field during preparation show a slightly greater magnetic response compared with both nanosheets without magnetic field exposure and nanosheets prepared at low poly (L-lactide) concentrations.

scholarly journals Experimental Investigation of Magnetic Particle Movement in Two-Phase Vertical Flow under an External Magnetic Field Using 2D LIF-PIV

2020 ◽  
Vol 10 (11) ◽  
pp. 3976
Author(s):  
Changje Lee ◽  
Yong-Seok Choi
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Particles ◽  
Magnetic Particle ◽  
Two Phase Flow ◽  
Scattered Light ◽  
Laser Sheet ◽  
Phase Flow ◽  
Particle Movement ◽  
Two Phase

In this study, we experimentally investigated magnetic particle movement in two-phase flow under an external magnetic field. According to Faraday’s law, the alignment of a magnet is important for power generation. For high generation, it is important to understand how magnetic particles move in two-phase flow. The rotationality could be determined by observing a single particle; however, this is impossible due to the flow conditions. In this study, we estimated nonrotationality based on the vorticity. To eliminate scattered light and improve the signal-to-noise ratio, the laser-induced fluorescence particle image velocimetry technique was used. The solenoid nozzle has a hydraulic diameter of 3 mm. Its surface is covered with a coil with a diameter of 0.3 mm. The average diameter of a magnetic particle is 1.2 μm. The excitation and emission wavelengths are 532 and 612 nm, respectively. A thin laser sheet setup was configured. The laser sheet was illuminated on both sides to prevent shadows. The images were captured at 200 μm away from the wall and center of the nozzle. To estimate the decrease in vorticity, the theoretical and single-phase non-magnetic and magnetic particles are compared. The vorticity of magnetic particles is reduced by the external magnetic field.

scholarly journals Direct Measurement of Temperature Diffusivity of Nanocellulose-Doped Biodegradable Composite Films

Micromachines ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 738 ◽  
Author(s):  
Hiroki Fujisawa ◽  
Meguya Ryu ◽  
Stefan Lundgaard ◽  
Denver P. Linklater ◽  
Elena P. Ivanova ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Direct Measurement ◽  
Cross Sections ◽  
Polymer Films ◽  
Composite Films ◽  
Polymer Nanocomposite ◽  
Optical Transmittance ◽  
Nanocomposite Films ◽  
Contact Method ◽  
Resistance Change

The thermal properties of novel nanomaterials play a significant role in determining the performance of the material in technological applications. Herein, direct measurement of the temperature diffusivity of nanocellulose-doped starch–polyurethane nanocomposite films was carried out by the micro-contact method. Polymer films containing up to 2 wt%. of nanocellulose were synthesised by a simple chemical process and are biodegradable. Films of a high optical transmittance T≈80% (for a 200 μm thick film), which were up to 44% crystalline, were characterised. Two different modalities of temperature diffusivity based on (1) a resistance change and (2) micro-thermocouple detected voltage modulation caused by the heat wave, were used for the polymer films with cross sections of ∼100 μm thickness. Twice different in-plane α‖ and out-of-plane α⊥ temperature diffusivities were directly determined with high fidelity: α‖=2.12×10−7 m2/s and α⊥=1.13×10−7 m2/s. This work provides an example of a direct contact measurement of thermal properties of nanocellulose composite biodegradable polymer films. The thermal diffusivity, which is usually high in strongly interconnected networks and crystals, was investigated for the first time in this polymer nanocomposite.

scholarly journals Controlling optical transmission through magneto-plasmonic crystals with an external magnetic field

2008 ◽  
Vol 10 (10) ◽  
pp. 105012 ◽  
Author(s):  
G A Wurtz ◽  
W Hendren ◽  
R Pollard ◽  
R Atkinson ◽  
L Le Guyader ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Optical Transmission ◽  
Plasmonic Crystals

Development of Field-responsive Polymeric Magnetic Composite Fibers via Electrospinning

2004 ◽  
Vol 855 ◽  
Author(s):  
M. Wang ◽  
H. Singh ◽  
T.A. Hatton ◽  
G.C. Rutledge
Keyword(s):  
Magnetic Field ◽  
Mathematical Model ◽  
Magnetic Properties ◽  
External Magnetic Field ◽  
Magnetite Nanoparticles ◽  
Magnetic Composite ◽  
Composite Fibers ◽  
Uniform External Magnetic Field

ABSTRACTA mathematical model is developed to predict the changing stiffness of magnetic fibers within a uniform external magnetic field. Magnetite nanoparticles 16nm in diameter were synthesized by an organic route. An ultrafine PMMA fiber containing 16nm magnetite nanoparticles was produced by electrospinning. The magnetic properties of the fibers were also characterized.

A novel Fe2O3–Fe3O4@SiO2@TiO2–TNS–GR magnetic composite with an enhanced visible photocatalytic property

2019 ◽  
Vol 12 (02) ◽  
pp. 1950006 ◽  
Author(s):  
Weiqiang Yang ◽  
Xiaowen Liu
Keyword(s):  
Magnetic Field ◽  
Photocatalytic Activity ◽  
External Magnetic Field ◽  
Degradation Rate ◽  
Solvothermal Method ◽  
Photocatalytic Property ◽  
Magnetic Composite ◽  
Sem Images ◽  
Xrd Diffraction ◽  
Diffraction Patterns

A novel magnetic Fe2O3–Fe3O4@SiO2@TiO2–TNS–GR had been synthesized via a solvothermal method. The XRD diffraction patterns and SEM images showed that the magnetite Fe2O3–Fe3O4 core was coated with amorphous SiO2 sheel and anatase sheel successively. TiO2 nanosheets (TNS) and Fe2O3–Fe3O4@SiO2@TiO2 had been loaded on the graphene (GR) sheets successfully. The degradation rate of Fe2O3–Fe3O4@SiO2@TiO2–TNS–GR for rhodamine B (RhB) under visible light irradiation reached 93.34%, which was much higher than that of Fe3O4@SiO2–TNS–GR. The Fe3O4 made the composite to be easily separated from the suspension with an external magnetic field, and [Formula: see text]-Fe2O3 had enhanced the photocatalytic activity of the composite.

scholarly journals The influence of concentration of Nd-Fe-B powder in composite coating of optical fiber to the sensibility to external magnetic field

2005 ◽  
Vol 41 (1) ◽  
pp. 103-111 ◽  
Author(s):  
Vesna Radojevic ◽  
T. Serbez ◽  
R. Aleksic ◽  
D. Nedeljkovic ◽  
Lj. Brajovic
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Optical Fiber ◽  
Composite Coating ◽  
Optical Fibers ◽  
Optical Fiber Sensor ◽  
Light Signal ◽  
Magnetic Composite ◽  
Sensor Element ◽  
Optical Propagation

Multi-mode optical fiber with magnetic composite coating was investigated as an optical fiber sensor element (OFMSE) for magnetic field sensing The composite coating was formed with dispersions of permanent magnet powder of Nd-Fe-B in poly (ethylene-co-vinyl acetate)-EVA solutions in toluene. The influence of the applied external magnetic field on the change of intensity of the light signal propagate trough developed optical fibers sensor element was investigated. In this paper the influence of the content of magnetic powder in the composite coating on the optical propagation characteristics of optical fiber were particularly investigated.

Development of magnetite nanoparticles/gelatin composite films for triggering drug release by an external magnetic field

2018 ◽  
Vol 152 ◽  
pp. 78-87 ◽  
Author(s):  
Tíffany Marín ◽  
Paula Montoya ◽  
Oscar Arnache ◽  
Rodolfo Pinal ◽  
Jorge Calderón
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Drug Release ◽  
Magnetite Nanoparticles ◽  
Composite Films
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