Formation of agglomerates in a complex diluted liquid in absence of the magnetic field [articol]

Abstract

The complex fluids, magnetic fluids used in technological applications in particular, should be stable so that the parameters of the installations don’t change over time. Colloid, a ferrofluid in particular, is stable if aggregates formed under the effect of London and Van der Waals forces between solid particles (particularly magnetite), have small dimensions. This paper continues and develops the studies concerning the optical properties of ferrofluids [3] and shows that the dimensions of the aggregates can be estimated by measuring the spectral absorption coefficient. Since the size of aggregates from complex fluids influences the stability and opportunity of their utilization in practical applications, the purpose of our paper is to estimate, using optical methods, the dimensions and numbers of he solid particles from aggregates which are formed in a very diluted complex liquid. In this case, using optical measurements of the spectral absorption coefficient, the size of aggregates varies from 11 to 44 nm. Average number of nano-particles is 4. The ferrofluid studied is stable and, thus, can be trustfully used in technological and biological applications.