Formulation characteristics, phase and physicochemical behaviours of <i>n</i>-heptane/AOT/water microemulsion in the presence of water soluble polymers

Abstract

The formation characteristics (phase behaviours) and physicochemical properties (conductance and Viscosity) of <i>n</i>—heptane/AOT/water microemulsion have been studied in the presence of a number of addtives (water soluble polymers) viz. carboxymethylcellulose, starch, polyethylene glycol, gelatine and polyacrylamide. It has been found that a significant monophasic microemulsion (Winsor type IV) can be realised in the presence of all the polymers except for carboxymethylcellulose. The microdispersions are stabIe, conducting and viscous. The normal mode of percolation of conductance with a threshold temperature of 40°C has been observed in all the cases except for 10% polyethylene glycol 6000 showing a lowering of the percolation threshold. The dispersions are essentially non-Newtonian in their flow behaviours. The shear viscosities have been found to depend on the type of polymer. The preparations have exhibited shear rate dependent thinning and thickening properties.