Répartition angulaire de la lumière diffusée par une solution de copolymères

Small‐Angle Scattering of X‐Rays and Neutrons

“…This technique was introduced into SANS by Ibel and Stuhrmann (1975) on the basis of previous results of X-ray crystallography (Bragg and Perutz, 1952), SAXS (Stuhrmann and Kirste, 1965), and light scattering (Benoit and Wippler, 1960). For scattering "particles" in solution, bulk contrast variation is obtained with mixtures of "light" and "heavy" solvents available in protonated and deuterated forms (H20, ethanol, cyclohexane, etc.).…”

“…This is not very practical for X-rays, since the transmission of the beam traversing the sample is a strong function of the wavelength. An alternative solution pioneered by Bonse and Hart (1966), is to use non-focussing optics. The monochromator is a multiple-bounce monolithic single crystal which provides a clean parallel beam on the sample.…”

“…opals, where spherical particles of amorphous silica form a closed-packed lattice with cell dimensions of up to several thousands of A, can still be investigated easily with neutrons. X-ray double-crystal diffractometers (Bonse and Hart, 1966) may also reach very low q.…”

Influence of fluctuations in electron density on the excess small‐angle X‐ray scattering from dilute solutions of macromolecules

“…21 In neutron scattering it is the scattering length and in light scattering it is the refractive index which determines the intensity. The greater difference in scattering length between hydrogen and deuterium allows one to vary the scattering density of the solvent water over a greater range of values than is usually the case in X-ray scattering, where there is no corresponding feature which can be exploited.…”

Light Scattering

“…Benoit et al in a series of papers (29,31,64,(278)(279)(280)(281) explored, theoretically and experimentally, this problem. They showed that in the case of block copolymers, consisting of two kinds of monomeric units of different refractive indices, a study of the apparent molecular weight as a function of the refractive index of solvent gives information about the polydispersity in composition.…”