Aggregation of needle-like macro-clusters in thin layers of magnetic fluid

Černák, Jozef

doi:10.1016/0304-8853(94)90321-2

Cited by 18 publications

(3 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Cernák investigated the evolution of field-induced aggregation of magnetic particles into needlelike clusters. Their experimental results showed that the average chain length increased with time, obeying a power law.…”

Section: Introductionmentioning

confidence: 99%

Secondary-Minimum Aggregation of Superparamagnetic Colloidal Particles

et al. 2000

View full text Add to dashboard Cite

This article investigates secondary-minimum aggregation of superparamagnetic colloidal latex particles. Chain formation and breakup are experimentally observed by using visualization techniques. The secondary minimum of the potential energy between two particles is determined from potential energy calculations, which include van der Waals, electrostatic, and magnetic dipole forces. A trajectory analysis, which incorporates these interparticle forces, hydrodynamic resistance forces, as well as gravity and magnetic induction forces, is also used to determine the secondary minimum. Furthermore, this study describes relative mobility functions caused by magnetic induction between two approaching particles. The effects of the following factors on the location of the secondary minimum are investigated: external magnetic field strength; particle size; and solution properties, such as ionic strength, zeta potential, and particle magnetic susceptibility. Both potential energy calculations and trajectory analysis lead to the same conclusion: the secondary-minimum separation decreases with increasing magnetic dipole force, decreasing electrostatic force, and increasing particle size and size ratio. After the removal of the magnetic field, three regimes of chain behavior may be identified: (i) no breakup regime, in which chains do not break, indicating primary-minimum aggregation; (ii) slow breakup regime; and (iii) fast breakup regime. Primary-minimum aggregation occurs when the chains are formed in high-ionic-strength solutions or at the pH of zero charge. Slow breakup occurs when the chains are formed under a low-strength magnetic field, while fast breakup occurs when the chains are formed under a high-strength magnetic field.

show abstract

Section: Introductionmentioning

confidence: 99%

Secondary-Minimum Aggregation of Superparamagnetic Colloidal Particles

et al. 2000

View full text Add to dashboard Cite

show abstract

“…Aggregation of magnetic particles has been studied for several reasons, including the need for the removal of particles from potable water/wastewater and ultrafine mineral streams and the investigation of magnetorheological fluids, , that is, magnetic particles immersed in a nonmagnetic liquid. Upon the application of a magnetic field, the induced dipoles quickly result in aggregation and chain formation along the direction of the applied field. , The potential energy between colloidal superparamagnetic particles has been studied based on the extended DLVO theory, which incorporates van der Waals, electrostatic, and magnetic−dipole forces . It was found that if the electrostatic force is strong enough to prevent aggregation, the presence of a magnetic force, which is of longer range than the electrostatic and van der Waals forces, causes a secondary minimum in the potential energy.…”

Section: Introductionmentioning

confidence: 99%

Probing DLVO Forces Using Interparticle Magnetic Forces: Transition from Secondary-Minimum to Primary-Minimum Aggregation

2001

View full text Add to dashboard Cite

The transition from secondary-minimum to primary-minimum aggregation of superparamagnetic colloidal latex particles is investigated in this study. The magnetic induction needed for this transition is calculated from the extended Derjaguin−Landau−Verwey−Overbeek (DLVO) theory, which includes van der Waals, electrostatic, and magnetic−dipole forces as well as non-DLVO hydrophobic attraction. A chain−dipole model is used to estimate the magnetic−dipole potential. The magnetic induction at which the transition from secondary- to primary-minimum aggregation occurs is experimentally determined from visualization of chain formation and breakup. Experimental and theoretical values of transitional magnetic induction show good agreement for the small particles used in this study. The experimental value of the transitional magnetic induction of relatively large particles in a narrow capillary tube is found to deviate significantly from that predicted by theory. However, the transitional magnetic induction obtained from a wide capillary agrees well with the theoretical value. This behavior indicates that, in the narrow capillary, the magnitude of the repulsive force between the particles decreases.

show abstract

“…Many researchers have successfully assembled arrays with 3D structures by inducing magnetic fields. However, these structures are typically produced in the magnetic liquid, and are very difficult to maintain once the magnetic field is removed [8][9][10]. In order to obtain 3D arrays which can be maintained without a magnetic field, needle-like microarrays were fabricated on film surfaces by combining cobalt particles with fluorocarbon (FC) resin [11].…”

Section: Introductionmentioning

confidence: 99%

Influences of different parameters on the microstructure of magnetic-field-induced self-assembled film

Yang

2016

IOP Conf. Ser.: Mater. Sci. Eng.

View full text Add to dashboard Cite

Theoretical study of the morphology of self-assembled amphoteric oxide colloid nanocrystals in weak electrolyte solutions A V Alfimov, E M Aryslanova and S A Chivilikhin -Magnetic-field-induced 1st order transition to FFLO state at paramagnetic limit in 2D superconductors N A Fortune, C C Agosta, S T Hannahs et al. Nanjing Xiaozhuang University, School of Environmental Science, Nanjing, P.R. China E-mail: xiaozhuangxxc2010@126.com Abstract. Self-assembled films with needle-like microarrays were fabricated using a mixture of cobalt and fluorocarbon resin under a magnetic field. The various influences of magnetic powder content, viscosity and size distribution on the structure of the self-assembled films were investigated. The self-assembled film morphologies were characterized by stereomicroscope and scanning electron microscopy. Experimental results indicate that an increase in magnetic powder content results in greater unit height and diameter, and that a reduction in viscosity results in increasing array density and decreasing unit width. Additionally, particles with narrow size distribution were able to attain more regular microarray structures. The structural alterations were closely related to numerous effects such as van der Waals forces, dipole-dipole interactions, and external-dipole interactions. The self-assembled film demonstrated magnetic anisotropy, as identified by vibrating sample magnetometry (VSM).

show abstract

Aggregation of needle-like macro-clusters in thin layers of magnetic fluid

Cited by 18 publications

References 19 publications

Secondary-Minimum Aggregation of Superparamagnetic Colloidal Particles

Secondary-Minimum Aggregation of Superparamagnetic Colloidal Particles

Probing DLVO Forces Using Interparticle Magnetic Forces: Transition from Secondary-Minimum to Primary-Minimum Aggregation

Influences of different parameters on the microstructure of magnetic-field-induced self-assembled film

Contact Info

Product

Resources

About