Shear-induced orientation of a rigid surfactant mesophase
Date of Original Version
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°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 Theological characterization and small-angle neutron scattering (SANS). The Theological 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°C, indicating the potential to conduct templated polymer and polymer-ceramic composite materials synthesis in aligned systems.
Publication Title, e.g., Journal
Singh, Mohit, Vivek Agarwal, Daniel De Kee, Gary McPherson, Vijay John, and Arijit Bose. "Shear-induced orientation of a rigid surfactant mesophase." Langmuir 20, 14 (2004): 5693-5702. doi: 10.1021/la049700y.