Rheological characterization of ferrous sulfate-containing water-in-oil-in-water (W1/O/W2) double emulsions

With use of response surface methodology (RSM), the W-1/O/W-2 emulsions containing ferrous sulfate as the inner phase were optimized in terms of stability (ES) and apparent viscosity (mu (app) ). Curvature display of the responses around their optimal settings was appropriately described using the quadratic polynomial regression model. The non-Newtonian behavior of the test W-1/O/W-2 emulsions was characterized using the power-law model and change from non-Newtonian to Newtonian (na parts per thousand integral 1) was seen in the case of W-1/O:W-2 ratio equal 20: 80 when the level of Tween-80 was 1 v%. Results of the size distribution pattern showed 60% of the particles were less than 5 mu m. Rheological properties of the test W-1/O/W-2 emulsions as the viscoelastic liquids were analyzed and the results of oscillatory experiments considering shear stress and frequency dependency of G' and GaEuro(3) moduli were discussed in terms of the internal microstructure of the emulsions.