Does compressibility affect the results obtained by small angle neutron scattering?
Résumé
Recently a few papers have been devoted to the scattering by polymer solutions and blends(1,2) assuming that the systems under investigation are compressible, contrarily to what is usually done. This is motivated by the fact that if one uses the theory of incompressible mixtures in scattering experiments, one obtains values of the Flory(3) χ parameter which are inconsistent with the values obtained by other techniques. In this paper we would like to show that, contrarily to what has been said, the effect of compressibility can be easily evaluated; it is very small and already corrected in the classical treatment of the data used in light or neutron scattering experiments.