In situ investigation of the liquid/solid interface of a block copolymer solution under shear stress using microbeam grazing-incidence small-angle x-ray scattering

An aqueous solution of poly(isoprene55-block-ethylene oxide170) was investigated at different temperatures combining rheometry in plate/plate-geometry and microbeam grazing incidence small-angle x-ray scattering. In the vicinity of the rotator plate, we were able to separate the bulk scattering of the solution from the grazing incident signal stemming of the interface and to determine a thickness of an interface layer at the liquid-solid interface. We followed the thickness of the interface layer in situ as a function of shear rate. This kind of measurements can be important to decide if the first micellar layer sicks or slips at the surface under shear.