Investigation of microstructure and dynamics of novel gemini surfactant micelles by small-angle neutron scattering (SANS) and NMR self-diffusion

The microstructure and dynamics of ANHG550 micelles were investigated at various concentrations by small-angle neutron scattering and NMR self-diffusion. This type of surfactant is of interest from both academic and industrial viewpoints due to the absence of any real "spacer", and nonidentical headgroups resembling a mixed system of an anionic and a nonionic surfactant built into the same molecule. The ANHG550 surfactant exhibits a cooperative aggregation without formation of premicellar aggregates in accordance with previous fluorescence and surface tension measurements. Various models for the form factor have been considered for fitting the SANS scattering patterns. Results obtained from SANS analysis and PGSE NMR are both found to be consistent with ellipsoidal micelles. No obvious micelle size growth was noticed in the concentration range studied. This runs contrary to the behavior of many other geminis with variable spacers.