Controlling the morphological characteristics in surfactant micelles credits desired properties and enhances its performance. Addition of electrolytes (inorganic salts) and nonelectrolytes (short chain alcohols) to the aqueous solution of cationic surfactants induce micellar growth and undergo microstructural transformation from spherical to long, flexible wormlike, conveying viscoelastic properties to the solutions. Changes in the dimensional parameters of the amphiphilic micelles in presence of additives were inferred from dynamic light scattering (DLS) and small angle neutron scattering (SANS) measurements.
Scattering results suggested the one-dimensional change in micellar growth which is attributed to the screening of the head-head repulsion between amphiphiles, thereby reducing the interfacial curvature of the aggregate with increasing salt concentration. The lower or medium chain alcohols behave uniquely as they distribute themselves between the bulk and micellar pseudophase thus favoring the stable micellar system.
Other complementary techniques viz., viscosity, steady and dynamic rheology, and cryogenic-transmission electron microscopy (cryo-TEM) were also employed in surfactants with the aim of achieving a tool to methodically tune the self-assembly characteristics in presence of additives.
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