Direct observation of shear-induced orientational phase coexistence in a lyotropic system using a modified x-ray surface forces apparatus

The behavior of lamellar fluid samples in relatively large gaps was studied to maximize the scattering signal with the in-house rotating anode x ray set up. The XSFA-II was used to study a four-component lyotropic model lubricant system. By applying small shear amplitudes to a relatively thick film, evidence was observed for the formation of an atom orientational boundary layer at the shearing surface. Time-resolved x-ray diffraction revealed the gradual transition.