Detection of structural transformations in magnetic fluids for biomedical application by ultrasound

Acoustic spectroscopy has been used to investigate the effect of surface-coating layers in biocompatible magnetic fluids. The method applied is sensitive to structural changes in the suspension as the ultrasonic attenuation is correlated with the concentration of particles and the particle size distribution. The structural characteristics (aggregation phenomena) of the magnetic fluids with a single and double layer of a surfactant on magnetic field sweep have been analyzed on the basis of ultrasound attenuation measured for different frequencies of the acoustic wave.