title: Shear-induced orientation of a rigid surfactant mesophase.
abstract: An optically clear, crystalline, gel-like mesophase is formed by the addition of water to a micellar solution consisting of a mixture of 0.85 M anionic surfactant sodium bis(2-ethylhexyl) sulfosuccinate (AOT) and a 0.42 M zwitterionic surfactant phosphatidylcholine (lecithin) in isooctane. At 25 degrees C and water to AOT molar ratio of 70, the system has a columnar hexagonal microstructure with randomly oriented domains. The shear-induced orientation and subsequent relaxation of this structure were investigated by rheological characterization and small-angle neutron scattering (SANS). The rheological response implies that the domains align under shear, and remain aligned for several hours after cessation of shear. Shear-SANS confirms this picture. The sheared gel mesophase retains its alignment as the temperature is increased to 57 degrees C, indicating the potential to conduct templated polymer and polymer-ceramic composite materials synthesis in aligned systems.
authors.affiliation: Department of Chemical Engineering, Tulane University, New Orleans, Louisiana 70118, USA.
authors.forename: Mohit
authors.initials: M
authors.lastname: Singh
authors.forename: Vivek
authors.initials: V
authors.lastname: Agarwal
authors.forename: Daniel
authors.initials: D
authors.lastname: De Kee
authors.forename: Gary
authors.initials: G
authors.lastname: McPherson
authors.forename: Vijay
authors.initials: V
authors.lastname: John
authors.forename: Arijit
authors.initials: A
authors.lastname: Bose