Droplet−Droplet Interactions in Both Direct and Inverse Emulsions Stabilized by a Balanced Amphiphilic Polyelectrolyte

An original amphiphilic polyelectrolyte was used as an emulsifier of the n-hexadecene−water system. The balanced hydrophile−lipophile properties of the polymeric surfactant allow the preparation of both oil and water continuous emulsions with dispersed phase volume fractions of up to 0.9. The oil and water droplet interactions were investigated by dynamic rheology and optical microscopy. In contrast to oil droplets, water droplets are strongly adhesive so that fractal gels can form in inverse emulsions. Hence, the Princen theoretical model on emulsion elasticity gives adequate fitting of the rheological behavior of direct emulsions but fails in describing the behavior of inverse emulsions.