Monomer Dynamics in SDS Micellar Solution

Monomer dynamics in sodium dodecyl sulfate (SDS) micellar solution at room temperature as studied by quasi elastic neutron scattering (QENS) technique is reported. The elastic incoherent structure factor (EISF) obtained from the analysis of QENS data suggests that the SIDS chains perform uniaxial rotational diffusion along the long Molecular axis. The rotation diffusion coefficient was found to decrease with the increase in the concentration of the surfactants. It is observed that on addition of electrolyte (0.8 M NaCl) the motion is arrested. Addition of salt is known to induce the growth in SIDS micelles, here it is found to affect the dynamics of monomers also. This is due to the combined effect of closer packing of the monomers within the micelle and the tendency of amphiphilic molecules to stabilize due to the presence of electrolytes.