Investigation of the pH effect on the stability of biocompatible magnetic fluids using time-dependent birefringence measurements

• Published in: Journal of magnetism and magnetic materials Vol. 289; pp. 448 - 451
• Main Authors: Gravina, P.P., Bakuzis, A.F., Skeff Neto, K., Azevedo, R.B., Morais, P.C.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2005; Elsevier Science
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Fine particle systems; Magnetic liquids; Magnetic properties and materials; Magnetooptical effects; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Physics; Studies of specific magnetic materials; 75.50.Mm; 75.50.Tt; 78.20.Ls; Fine particle systems; Magnetooptical effects; Magnetic liquids; Time dependence; Ferromagnetic fluid; Magnetic birefringence; Fine particle; 78.20.Ls Magnetic liquids; Magneto-optical effects; Coated material
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2004.11.126

In this work we used the static magnetic birefringence together with transmissivity measurements to investigate the effect of the pH on the stability of a water-based, citrate-coated, maghemite magnetic fluid as a function of the time. We observed a peak on the SMB measurement due to the high birefringence of the material. The peak position shifted to lower field values as a function of time and decreasing the pH of the sample. The phenomena is explained as a result of agglomerate formation. In addition, the conductivity constant decreases by 6% changing the pH value of the sample from pH = 10 to pH = 7 .