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Small‐angle X‐ray scattering from block copolymers as an ideal model system for a pseudo two‐phase solid texture
Author(s) -
Todo A.,
Hashimoto T.,
Kawai H.
Publication year - 1978
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/s0021889878013874
Subject(s) - small angle x ray scattering , scattering , materials science , phase (matter) , optics , small angle scattering , physics , crystallography , chemistry , quantum mechanics
The microdomain structure of polystyrene‐polyisoprene A‐B type block copolymers was analysed by small‐angle X‐ray scattering (SAXS) as an ideal model system for a pseudo two‐phase solid structure. The structure was analysed in terms of spatial distribution, size, and the interracial structure of the dispersed domains of one component ( A segments) in the matrix of the other ( B segments). The SAXS analyses were performed with two collimating systems, a Rigaku Denki camera (essentially a four‐slit system with the addition of Soller slits) and a Kratky camera, which had widely different slit‐length and slit‐width weighting functions and was used to investigate instrumental effects, especially the role of the Soller slits in the obtaining of reliable desmeared intensity data in the tail of the SAXS curve. Comparison of the results indicated that the Soller slits facilitate the accurate evaluation of the interfacial thickness from the desmeared intensity data in the tail. The accuracy of the infinite slit‐height approximation and the effect of truncating the higher‐order terms in I h (the intensity associated with the interphase) on the estimated interfacial thickness are discussed. The infinite slit‐height approximation leads to values 25–35% smaller than the exact value (23 Å), and the truncation also leads to a value of the interfacial thickness smaller (19 Å) than the value (23 Å) based on the full analysis. The value obtained is in good agreement with the values predicted from the statistical‐mechanical theories of block copolymers in bulk.