BARC/PUB/2011/0081

 
 

Macroscopic and microscopic structural integrity in magnetic colloids-cationic micellar solution: Rheology, SANS and magneto-optical study

 
     
 
Author(s)

Patel, R.; Upadhyay, R. V.; Aswal, V. K.; Joshi, J. V.; Goyal, P. S.

Source

Journal of Magnetism and Magnetic Materials, 2011. Vol. 323 (6): pp. 849-856

ABSTRACT

A stable mixture of two colloid system composed of double surfactant coated aqueous nano magnetic fluid and aqueous micellar solution of cationic micelles of cetyletrymethyl ammonium bromide(CTABr) is prepared as a function of nano magnetic fluid concentration. This mixed systemis analyzed using three  techniques such as zero field and field induced viscosity measurements, Small Angle Neutron Scattering technique and magneto-optical birefringence measurements. In field induced viscosity measurement it is observed that even 20% magnetic fluid concentration inCTABr aqueous solution shows 75% increase in iscosity compared to pure magnetic fluid. This suggests that in presence of CTABr micelles, an ovel magnetorheological effect for low concentration of magnetic fluid is observed. From SANS measurements  it is observed that aggregation number and a/b ratio increases with magnetic fluid concentration and  magnetic birefringence reveals non-super impose behavior of normalized field induced retardation. Results of these experiments are compared and indicate zero fields and field induced structural integrity between magnetic particles and soft micelles.

 
 
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