Scattering from Dilute and Lamellar Phase Solutions of Aerosol-OT Simultaneous Probe of Surface Structures and Bulk

• The benefits of simultaneous studies of adsorbed layers and bulk structures are shown for solutions of the surfactant Aerosol-OT. Above the critical micelle concentration, Aerosol-OT forms an aligned lamellar phase at the sapphire/solution interface which is in equilibrium with a bulk phase that consists of coexisting micellar solution and dispersed lamellar phase. Measurements of the aligned surface layers and the bulk scattering from a 2% wt solution by grazing incidence and small-angle neutron scattering show that the bulk consist of lamellar structures with the same d-spacing as seen at the surface but without the surface induced alignment. The surface lamellar structure corresponds to a 10% volume fraction for a 2% wt bulk which implies that there must be coexistence of regions of different concentration. Scattering patterns measured in grazing incidence geometry clearly show the relative contributions from small-angle scattering and specular reflectivity.

Subject headings

NATURVETENSKAP  -- Kemi -- Polymerkemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Polymer Chemistry (hsv//eng)

Keyword

sodium bis 2-ethylhexyl sulfosuccinate

lamellar phase

scattering

Publication and Content Type

ref (subject category)

kon (subject category)