Concentration Of Ferrofluid Research Articles

Kinetics and Mechanism of Two-Electron Reduction of Surfacial Ferric Ions of Colloidal Ferrofluid by[formula omitted]-Ascorbic Acid in Aqueous Acidic Medium

The kinetics of electron transfer froml-ascorbic acid (H2A) to ferrofluid (FF) in dilute aqueous acidic solutions (pH 2.5–4.0) was investigated spectrophotometrically in detail as a function of [H2A], [FF], [H+], ionic strength, and temperature. FF was found to be reduced and the reduction was first-order dependent on both H2A and FF concentrations. An inverse first order dependence in H+ion concentration and no dependence on ionic strength were observed. Kinetic, electrochemical, spectrophotometric, and thermodynamic results are interpreted in terms of a mechanism involving a rate-determining outer-sphere one-electron transfer from H2A to FF followed by a subsequent and kinetically rapid transfer of the second electron of H2A to the same molecule of FF, which was already reduced by one electron in rate-determining step. This overall two-electron transfer process from H2A to the same molecule of FF is discussed and compared with other closely related reactions.

Collinear mirage effect measurement of the thermal diffusivity in ferrofluids

Thermal diffusivity results obtained for different concentrations of the same ferrofluid are reported. The collinear mirage technique was used for its adequacy in obtaining the thermal properties of semitransparent materials with low thermal diffusivities. The results show that, as the ferrofluid concentration increases, the thermal diffusivity also increases, leading to a different trend compared to those reported for ferronematics. The different behaviors observed can be related to the different geometries of thermal waves propagating throught the material.

Determination of the minimum concentrations of ferrofluid of CoFe2O4 required to orient liquid crystals

Abstract A lyotropic liquid crystal doped with CoFe 2 O 4 ionic ferrofluid with magnetic grains of different sizes is studied by means of optical techniques. The minimum concentrations of grains required to orient liquid crystals are determined. Brochard's and de Gennes' theory of magnetic suspensions is extended to include ellipsoidal grains.

Determination of the minimum concentration of ferrofluid required to orient nematic liquid crystals.

Determination of the minimum concentration of ferrofluid required to orient nematic liquid crystals.