Descriptive Measures for Anisotropic SAS: PCTE Membranes. Ty J. Prosa and John D. Barnes, Polymer Structure and Mechanics Group, N.I.S.T., Gaithersburg, MD 20899.

Polycarbonate track etched (PCTE) membranes offer a unique model system for studying the effects of structural parameters on modeled scattering behavior. The process by which these materials are prepared leads to a material consisting of nearly ideal cylindrical pores in a homogeneous polymer matrix. The diameters of the pores, as well as the orientation of their axes, are statistically distributed within relatively narrow ranges. We have used simulation methodologies to generate scattering patterns that can be compared directly with observed scattering patterns in order to extract meaningful measures of the cylinder dimensions and orientation textures. The choosing of sample orientations that maximize rather than minimize the anisotropic nature of the observed scattering, offers the greatest opportunity for separation of the various shape and distribution measures.