SANS investigation of valency effect of salts on water/AOT/dodecane microemulsion droplets

Small Angle Neutron Scattering (SANS) has been employed to demonstrate the formation and stabilization of water/AOT/dodecane microemulsion (water in oil) droplets. The droplet volume fraction φ plays an important role in determining the microemulsion structure, interaction and in tuning the strength of inter-droplet attractive interaction. We demonstrate that the inter and intradroplet interfacial properties can be modified and controlled by using mono and multivalent salts. The structure and interaction has been modeled using modified Ornstein-Zernicke relation. The addition of monovalent (NaCl) salt of 0.3M concentration to microemuslion system with varying droplet volume fraction significantly reduces the interdroplet interaction and increases the droplet stability. However, the role of mutlivalent ions are more complex and the electric repulsion comes into play while tuning the structure and interaction properties.