Thermodynamic and transport properties of non-magnetic particles in magnetic fluids

Magnetic composites, obtained on associating magnetic fluid with non-magnetic particles, offer interesting opportunities in separations, assemblies and other applications, where the microstructure of the composite can be altered reversibly by an external field without altering the composition. The goal of our work in this area is to develop computational and simulation tools to assist in the in-depth understanding of the thermodynamic and transport properties of such non-magnetic nanoparticles immersed in magnetic fluids under varying magnetic field conditions. Also, in this work we have studied the relaxation and magnetization characteristics of magnetic nanoparticle clusters in presence of low external magnetic fields. Theoretical analysis of such a complex system is difficult using conventional theories, and hence we have used Monte Carlo Simulations to explore these effects. We simulated the interactions between non-magnetic particles (1000 nm) and magnetic nanoparticles (10 nm and 20 nm diameter) dispersed in organic phase. We observed that the presence of the non-magnetic particle in the system induces magnetic non-homogeneity. The magnetic nanoparticles present in the equatorial place of the non-magnetic particle with reference to the applied magnetic field have a higher magnetization as compared to the particles in the polar region. This effect was much more dominant for 20 nm particles than 10nm particles, because the magnetic inter-particle interactions are much stronger for the larger particles. We have also studied the effect of radial distance from the nonmagnetic particle on the magnetization and radial distribution function characteristics of the magnetic nanoparticles.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2009

Author dc:creator

• Tejwani, Saurabh

Advisor dc:contributor.advisor

• T. Alan Hatton and Kenneth A. Smith.

• Chemical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/54584

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/54584