scholarly journals A Comparison Study on the Magneto-Responsive Properties and Swelling Behaviors of a Polyacrylamide-Based Hydrogel Incorporating with Magnetic Particles

2021 ◽  
Vol 22 (22) ◽  
pp. 12342
Author(s):  
Chanchan Xu ◽  
Bin Li ◽  
Xiaojie Wang
Keyword(s):  
Magnetic Particles ◽  
Filler Content ◽  
Comparison Study ◽  
Swelling Properties ◽  
Micro Particles ◽  
Magnetite Fe3o4 ◽  
Hydrogel Matrix ◽  
Water Swelling ◽  
Mr Effect ◽  
Swelling Behaviors

This work investigates the mechanical properties, microstructures, and water-swelling behavior of a novel hydrogel filled with magnetic particles. The nanoparticles of magnetite (Fe3O4) and the micro-particles of carbonyl iron (CI) were selected and filled into a polyacrylamide (PAAM) hydrogel matrix to create two types of magnetic hydrogels. The isotropy and anisotropy of magnetic hydrogels are also presented in this study. The isotropic samples were cured without applying a magnetic field (MF), and the anisotropic samples were cured by applying an MF in the direction perpendicular to the thickness of the samples. The effects of the size, content, and inner structures of magnetic particles on the magneto-responsive and swelling properties of magnetic hydrogels were investigated. It was found that the magnetorheological (MR) effect of anisotropic samples was apparently higher than that of isotropic samples, and the hydrogels with CI exhibited a noticeable MR effect than those with Fe3O4. The storage modulus can be enhanced by increasing the filler content and size, forming an anisotropic structure, and applying an external MF. In addition, the magnetic hydrogels also have a swelling ability that can be tuned by varying the content and size of the particle fillers.

scholarly journals Mechanical properties of magnetic gels containing rod-like composite particles

2019 ◽  
Vol 377 (2143) ◽  
pp. 20180218 ◽  
Author(s):  
Mariem M. Abrougui ◽  
Modesto T. Lopez-Lopez ◽  
Juan D. G. Duran
Keyword(s):  
Mechanical Properties ◽  
Magnetic Particles ◽  
Three Dimensional ◽  
Heterogeneous Systems ◽  
Soft Materials ◽  
Polymer Chains ◽  
Composite Particles ◽  
Magnetite Particles ◽  
Magneto Rheological ◽  
Mr Effect

Magnetic gels (ferrogels) are heterogeneous systems structured at the nanoscale that contains magnetic particles dispersed in three-dimensional networks of polymer chains. In the present work, the magnetic particles were synthesized with a core–shell structure, consisting of sepiolite particles covered by magnetite nanoparticles. These composite particles had a rod-like shape with a high aspect ratio. The obtained sepiolite–magnetite particles showed a high enough susceptibility and saturation magnetization. The magneto-rheological (MR) properties, and the intensity of the MR effect, of aqueous suspensions of the synthesized particles were studied. The particles, functionalized by adsorption of alginate molecules, were imbedded in alginate hydrogels to get homogeneous soft materials. The particles were linked to the polymer chains as the knots in a network and dominated in a great extent the mechanical properties of the materials. After determining the optimal compositions of the ferrogels, their viscoelastic properties were measured in the absence/presence of magnetic fields. The results pointed out that the MR effect provided by the clay–magnetite particles was considerably more intense than those achieved in ferrogels that contain spherical magnetic microparticles. Therefore, the imbedding of rod-shaped magnetic particles in hydrogels allows controlling the mechanical properties in a wider range than in conventional ferrogels. This article is part of the theme issue ‘Heterogeneous materials: metastable and non-ergodic internal structures’.

Swelling Behaviors and Water States of Fibrous Membranes Electrospun from PHBV-g-PVP

2012 ◽  
Vol 482-484 ◽  
pp. 1478-1482
Author(s):  
Wei Wang ◽  
Jian Da Cao ◽  
Ping Lan
Keyword(s):  
Water Absorption ◽  
Fiber Diameter ◽  
Bound Water ◽  
Free Water ◽  
Great Capacity ◽  
Electrospun Membranes ◽  
Dsc Characterization ◽  
Fibrous Membranes ◽  
Water Swelling ◽  
Swelling Behaviors

Fibrous membranes with a fiber diameter between 320 and 460 nm were electrospun from poly(3-hydroxybutyrate-co-3-hydroxyvalerate)-graft-poly(N-vinylpyrrolidone) (PHBV-g-PVP) and their specific water absorption behaviors were investigated for biomaterial purposes. Water swelling experiments indicate that all samples have a great capacity for water uptake, while a remarkable overshoot occurs for the membranes electrospun from PHBV-g-PVP other than those from PHBV. DSC characterization indicates that only non-freezable bound water and free water can be distinguished in all electrospun membranes.

Thermal Property Enhancement of Liquid Metal Used As Thermal Interface Material by Mixing Magnetic Particles

2019 ◽  
Author(s):  
Xianfeng Ma ◽  
Gen Li ◽  
Xuelin Zheng ◽  
Xiaozhong Wang ◽  
Zhongcheng Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
Liquid Metal ◽  
Magnetic Particles ◽  
Nickel Particle ◽  
Field Application ◽  
Thermal Interface Material ◽  
Thermal Interface ◽  
Micro Particles ◽  
Steady State Method

Abstract The usage of low melting temperature alloys (LMAs) as thermal interface materials (TIMs) has attracted more and more attention for their high thermal conductivity. However, the wettability between liquid metal and ordinary metal surface was poor, which results in high thermal interface resistance. The thermal and physical properties of LMAs can be modified by adding nano or micro particles. In this study, the room temperature liquid metal (gallium, indium and tin eutectic) was used as TIM and its properties were modified by mixing magnetic nickel particles. Further, the effects of magnetic field application on the thermal performance of modified LMAs were evaluated by steady state method with specially designed sample holder. Results showed that the thermal conductivity of liquid metal mixed with nickel particle increased from 27.33 W/(m · K) to 33.33 W/(m · K) with the application of magnetic field.

Patterned Magnetorheological Elastomer Developed by 3D Printing

2018 ◽  
Vol 939 ◽  
pp. 147-152 ◽  
Author(s):  
Anil K. Bastola ◽  
Milan Paudel ◽  
Lin Li
Keyword(s):  
Magnetic Field ◽  
3D Printing ◽  
Magnetic Particles ◽  
Layer By Layer ◽  
Carrier Fluid ◽  
Vibration Technique ◽  
Mode Of Operation ◽  
3D Printed ◽  
Mr Effect

This article delineates the characterization of the 3D printed MR elastomer through a forced vibration technique in the squeeze mode of operation. An anisotropic hybrid magnetorheological (MR) elastomer is developed via 3D printing. The 3D printed MR elastomer consists of three different materials; magnetic particles, magnetic particles carrier fluid, and an elastomer. MR fluid filaments are encapsulated layer-by-layer within the elastomer matrix using a 3D printer. When a moderately strong magnetic field is applied, the 3D printed MR elastomer changes its elastic and damping properties. The hybrid 3D printed MR elastomer also shows an anisotropic behavior when the direction of the magnetic field is changed with respect to the orientation of the printed filaments. The relative MR effect is higher when the applied magnetic field is parallel to the orientation of the printed filaments. The maximum change in the stiffness is observed to be 65.2% when a magnetic field of 500 mT is applied to the MR elastomer system. This result shows that the new method, 3D printing could produce anisotropic hybrid MR elastomers or possibly other types.

scholarly journals SYNTHESIS AND CHARACTERIZATION OF NOVEL SA-PA-LSA/C-30B/AG NANOCOMPOSITES FOR SWELLING, ANTIBACTERIAL, DRUG DELIVERY, AND ANTICANCER APPLICATIONS

2018 ◽  
Vol 11 (3) ◽  
pp. 229
Author(s):  
Nanjunda Reddy B H ◽  
Prdadipta Ranjan Rauta ◽  
Venkatalakshimi V ◽  
Swamy Sreenivasa
Keyword(s):  
Drug Delivery ◽  
Antibacterial Activity ◽  
Sustained Release ◽  
Polymerization Reaction ◽  
Antibacterial Drug ◽  
Hacat Cells ◽  
Swelling Properties ◽  
Hydrogel Matrix ◽  
Hydrogel Composites ◽  
Lignosulfonic Acid

 Objective: The main objective of this work was to formulate and evaluate Closite-30B/nanoAg filled hydrogel composites which are further intentended to be used for the study of drug delivery,antibacterial, and anticancer activityMethods: In this study, Cloisite-30B (C-30B) clay dispersed biopolymer sodium alginate (SA)-grafted-poly (acrylamide [AAm]-co-lignosulfonic acid) hydrogel composites were synthesized by free radical in situ polymerization reaction technique using SA, AAm, and lignosulfonic acid biopolymers in different proportions in combination. which are subjected to invitro drug delivery and Minimum inhibitory concentration(MIC) method for antibacterial activity study by using Streptococcus faecalis (S.faecalis) and Escherichia coli (E. coli)bacteria. The biocompatibility of the prepared gels were determined by standard protocol HaCaT-cells and MCF-7 cell lines further the prepared hydrogel composites were characterized for particle size,encapsulation efficiency,swelling properties,compatibility studies by FTIR etc.Results: The formulated hydrogels were characterized by X-ray diffraction (XRD) to analyze the particles size and crystallinity. The presence of functional groups and their chemical interaction with the drug, C-30B, and silver nanoparticles (AgNPs) were confirmed by the FTIR spectroscopy. Furthermore, the presence of AgNPs in the matrix was confirmed by ultraviolet/visible spectroscopy. Thermogravimetric analysis was performed to find out the thermal degradation, thermal stability, and the percentage of weight loss at various temperatures. Swelling studies revealed that C-30B and AgNPs induced composites exhibited higher swelling ratio than pure hydrogels. The hydrogels with C-30B/AgNPs displayed excellent antibacterial activity against both Gram-positive and Gram-negative bacteria. Further, these hydrogel composites were loaded with the drug paclitaxel (PT), and drug release study showed that the sustained release of the drug from C-30B/Ag hydrogel matrix compared to rest of other samples. Hydrogel composites were cytocompatible in nature (with HaCaT cells) and the cell viability decreased (with MCF-7cells) with the presence of lignosulfonic acid as well as C-30B and AgNPs in the samples as evaluated through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide to its insoluble formazan assay.Conclusion: The synthesized hydrogel composites were successfully characterized and eavaluated for sustained release of paclitaxel drug delivery at different pHs and temperatures and it is found that C30B/Ag filled composites exhibits contolled release of drug with higher rate, especially at lower pH (pH2) and higher temperature (37oC) and the same formulations which exhibits better anitbcterial and anticancer activity compared to the virgin samples So the prepared C30B/AgNPs hydrogels composites used in drug dlivery for the effective treatment of cancer and used against bacterias and cancerous cells.

Alignment of magnetic particles in hydrogel matrix: A novel anisotropic magnetic hydrogels for soft robotics

2020 ◽  
pp. 1045389X2097550
Author(s):  
Li Bin ◽  
Chanchan Xu ◽  
Shuai Dong ◽  
Xiaojie Wang
Keyword(s):  
Magnetic Field ◽  
Magnetic Particles ◽  
Artificial Muscle ◽  
Variable Stiffness ◽  
Polymer Chains ◽  
Soft Robotics ◽  
Ionic Conductors ◽  
Hydrogel Matrix ◽  
Anisotropic Structures ◽  
Particle Chains

Magnetic hydrogels are composed of magnetic particles and hydrogel matrix. In recent years, the magnetic hydrogels have been developed rapidly because they have shown promising applications in drug release and artificial muscle. In this paper, we proposed a study to develop novel anisotropic magnetic hydrogels and investigate their mechanical and sensing properties for possible applications in soft robotics. In preparing the anisotropic magnetic hydrogels, the polyacrylamide (PAAm) hydrogel is chosen as a model hydrogel because of its popular application in soft electronics and ionic conductors. A method of free radicals copolymerization is employed to fill (polyacrylic acid/acrylamide) polymers in preparing anisotropic hydrogels under the magnetic field. Unlike most of the previous studies which incorporated magnetic nanoparticles into hydrogels, we mixed the micro-size carbonyl iron particles (CIPs) with the hydrogel and cured them under a magnetic field to form anisotropic structures within its crosslinking polymer chains. The particles and formed particle chains will not only improve the mechanical properties of the hydrogels but also provide sensing function as the electrical resistance changed from mechanical deformation referred to piezoresistivity. We experimentally evaluated the magnetorheological and the piezoresistive behaviors of the magnetic hydrogels, and demonstrated their potential use in soft robots as flexible touch sensors and variable-stiffness devices.

A Novel Superfine Machining Technology Based on the Magnetorheological Effect of Abrasive Slurry

2006 ◽  
Vol 532-533 ◽  
pp. 145-148 ◽  
Author(s):  
Jia Bin Lu ◽  
Juan Yu ◽  
Qiu Sheng Yan ◽  
Wei Qiang Gao ◽  
Liang Chi Zhang
Keyword(s):  
Material Removal ◽  
Relative Velocity ◽  
Magnetic Particles ◽  
Applied Pressure ◽  
Grinding Wheel ◽  
Machined Surface ◽  
Abrasive Particles ◽  
Magnetorheological Effect ◽  
Mr Effect ◽  
Glass Surfaces

Based on the magnetorheological (MR) effect of abrasive slurry, this paper presents an innovative superfine machining method. In this technique, the particle-dispersed MR fluid is used as a special instantaneous bond to cohere abrasive particles and magnetic particles so as to form a dynamical tiny-grinding wheel. This tiny-grinding wheel can be used to polish the surface of brittle materials in millimeter or sub-millimeter scale. The characteristics of the machined glass surfaces examined by the scanning electron microscope (SEM) and the Talysurf roughness tester confirmed the effectiveness of the finishing technique. The machined surface with convex center and concave fringe demonstrates that the material removal process is dominated by the synergy of the applied pressure and the relative velocity between the abrasives and workpiece. In the case of glass finishing, the mode of material removal is found to be plastic, and controlled by the abrasive-wear mechanism.

Comparative Investigations of Structure and Absorptive Capacity of Nano- and Microsized Magnetic-Operated Particles for their Application in Medicine and Biology

2009 ◽  
Vol 152-153 ◽  
pp. 403-406 ◽  
Author(s):  
Yu.G. Yanovsky ◽  
L.Kh. Komissarova ◽  
A.N. Danilin ◽  
E.I. Zaraysky
Keyword(s):  
Hepatitis B ◽  
Absorptive Capacity ◽  
Magnetic Particles ◽  
Cobalt Ferrite ◽  
Virus Hepatitis ◽  
Sorption Efficiency ◽  
Magnetite Fe3o4 ◽  
First Time ◽  
Different Molecular Weight

For the first time, the comparative investigations of structure and sorption efficiency of nano- and microsized magnetic-operated particles in respect to both the antigen and virus hepatitis B and also to the substance-markers (low-, middle- and highmolecular substances) were carried out. The sorption efficiency of magnetic particles: magnetite (Fe3O4), cobalt-ferrite (CoFe2O4), composite ferro-carbon (FeC) to the substances of different molecular weight was evaluated in vitro experiments. The high absorptive capacity to low- and highmolecular substance-markers has been observed for microsized composites of FeC. Absorptive capacity of the nanosized Fe3O4 and CoFe2O4 particles to the substance-markers was low. But the nanosized Fe3O4 and CoFe2O4 particles had a good absorptive capacity to virus of hepatitis B and its antigen (HBsAg). The sorption efficiency results of nano- and microsized magnetic particles correlate with the structure of their surface.

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