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The determination of diffuse‐boundary thicknesses of polymers by small‐angle X‐ray scattering
Author(s) -
Koberstein J. T.,
Morra B.,
Stein R. S.
Publication year - 1980
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889880011478
Subject(s) - boundary (topology) , interphase , scattering , sigmoid function , materials science , thermal , intensity (physics) , function (biology) , computational physics , physics , optics , molecular physics , thermodynamics , mathematical analysis , mathematics , genetics , machine learning , evolutionary biology , artificial neural network , computer science , biology
Thermal density fluctuations within phases and finite interphase widths lead to systematic deviations from Porod's law. The validity of present methods used to analyze these deviations and determine diffuse‐boundary widths is determined. In view of the inadequacies found in these methods, a simple yet accurate method is proposed to determine the diffuse‐boundary width from direct graphical analysis of slit‐smeared intensity data. The diffuse interface is modelled by a sigmoidal‐gradient model which is justified on thermodynamic grounds, with the interphase thickness as a function of the Flory–Huggins interaction parameter.