Rheological study on diluted micellar solutions of CTAB/NaSal/KBr


Leal, C.1,2, Pereira, M.1 and Scheven, U.3

1 Instituto Superior de Engenharia de Lisboa, Portugal; 2 CENIMAT/I3N, Universidade Nova de Lisboa, Portugal; 3 Dep. Química da Faculdade de Ciências e Tecnologia e REQUINTE, Universidade Nova de Lisboa, Portugal.


Cetyltrimethylammonium Bromide (CTAB) in water forms spherical micelles, which upon addition of salts (NaSal or KBr) elongate to form entangled wormlike structures. The “worms” are stabilized by charge screening (NaSal and KBr), and by changes in the micellar surface energy as salicylate ions of (NaSal) intercalate in the CTAB micelles. Solutions of wormlike micelles exhibit dramatically increased viscosity, and visco-elasticity in the gel-like, highly entangled state. In this work we present a systematic rheological study for this surfactant, using Sodium Salicylate (NaSal) and Potassium Bromide (KBr) as added salts, with the aim of producing a fluid system exhibiting tuneable rheology. The influences of temperature and salt concentration were also observed and characterized in this work.