AN INTEGRATED COUETTE SYSTEM FOR IN-SITU SHEARING OF POLYMER AND SURFACTANT SOLUTIONS AND GELS WITH SIMULTANEOUS SMALL-ANGLE X-RAY-SCATTERING

A Couette cell designed for in situ small angle x-ray scattering (SAXS ) studies of polymeric systems under shear is described. Representativ e results are presented for the effect of shear on the lamellar phase of a concentrated poly(oxyethylene)-poly(oxybutylene) diblock copolyme r in aqueous solution. It is shown that the application of shear resul ted in a reduction in the lamellar spacing and of the defect density. The former was observed as a shift in the principal peak position in t he SAXS pattern, and the latter as an increase in the associated corre lation length. It was further shown that the cessation of shear led to a relaxation of both shear induced effects, over a time period of hou rs. (C) 1998 American Institute of Physics.