Fl. Calderon et al., ASPHALT EMULSIONS - FLOCCULATION INDUCED BY A CATIONIC SURFACTANT ANDAPPLICATION TO SIZE PARTITIONING, Colloids and surfaces. A, Physicochemical and engineering aspects, 74(2-3), 1993, pp. 303-309
The effect of excess surfactant on cationic asphalt-in-water emulsions
is investigated. At sufficiently high surfactant concentrations, reve
rsible flocculation occurs in polydisperse emulsions. We interpret suc
h a phenomenon as a fluid-solid phase transition due to the depletion
interactions exerted by surfactant micelles. Taking advantage of this
reversible transition, successful size partitioning is performed follo
wing a fractionated crystallization technique recently developed. Expe
rimental phase diagrams of monodisperse emulsions and microscopic obse
rvations confirm the fluid-solid description of this transition. The i
nfluence of an added electrolyte is also examined.