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Small‐angle X‐ray scattering by polymer solutions at intermediate concentrations
Author(s) -
Okana K.,
Wada E.,
Kurita K.,
Fukuro 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/s0021889878013758
Subject(s) - cyclohexane , small angle x ray scattering , dispersity , polymer , chemistry , ternary operation , small angle scattering , scattering , polystyrene , intensity (physics) , molecule , analytical chemistry (journal) , crystallography , physics , polymer chemistry , optics , organic chemistry , computer science , programming language
SAXS by solutions of monodisperse polystyrene at intermediate concentrations has been studied for the solvents having only a small volume‐exclusion effect, such as methyl ethyl ketone (MEK) and cyclohexane (CH). Both the density‐density correlation function of segments in solution and the osmotic compressibility, as obtained from the absolute intensity at zero angle, were measured for different concentrations and the results were successfully analysed by means of the recent theory of Moore [ J. Phys. ( Paris ), (1977), 38 , 265–271] . According to the theory, in the semi‐dilute poor‐solvent regime the concentration C , dependence of the screening length ξ , and the scattered intensity at zero angle I (0) are given by = 12 N A + 36 N 2 A C and = B 1 + 3 N A B 2 C , where M is the molecular weight of a polymer molecule, N A Avogadro's number and A 2 M the mean square end‐to‐end distance of an unperturbed chain; m 2 B 1 and m 3 B 2 are respectively the binary and ternary cluster integrals (or the first and the second irreducible integrals) for segments in solution, m being the molecular weight of a segment. ΔZ is the number of excess mole electrons per unit mass of segments. The measured concentration dependences were in agreement with the above prediction and the values of B 1 and B 2 were obtained.