Shear-Induced Formation of Ordered Monodisperse Emulsions Stabilized by an Associating Amphiphilic Polyelectrolyte

• DOI: 10.1021/la001492w
• Publication Date: 2007-05-30T15:27:13Z
• Authors: Patrick Perrin; Nicolas Devaux; Philippe Sergot; François Lequeux
• Keywords: Shearing (physics); Dispersity

An associating amphiphilic polyelectrolyte was used as an emulsifier of the n-dodecane−water system. First, dynamic rheological behavior polydisperse concentrated direct emulsions with dispersed phase volume fractions up to 0.91 investigated. Both Princen and Kiss (J. Colloid Interface Sci. 1983, 91, 160; 1986, 112, 427) Mason et al. (Phys. Rev. Lett. 1995, 75, 2051) approaches on emulsion elasticity give adequate fitting leading conclusion that mainly arises from droplet compression. Second, shear-induced formation ordered monodisperse studied. More specifically, conditions under which structures are obtained by shearing premixed within two-parallel circular glass plates a homemade shear apparatus were reported. The light scattering patterns, first-order ring, diffuse ring 6 bright spots, second-order 12 spots successively observed while samples reveal progressive layers hexagonal close-packed planes oil droplets rate increases. observation diffraction patterns also shows level organization decreases after cessation flow thus suggesting occupy well-defined spatial positions sample compared flow. radius forming colloidal crystal systematically measured function radial distance center slides, gap spacing, polymer concentration, content follow development long-range ordering emulsions. found depend only rate. Smaller increasing both slight change in size could be detected upon varying fraction phase. results qualitative agreement coalescence−fractionation mechanism shear.