Small-angle neutron scattering contrast variation

Knoll WK, Ibel K, Sackmann E. Small-angle neutron scattering 48. study of lipid phase diagrams by the contrast variation method. Biochemistry 1981 20 6379-6383. 

Arleth, L. and Pedersen, J.S. (2001) Droplet polydispersity and shape fluctuations in AOT [bis(2-ethylhexyl)sulfosuccinate sodium salt] microemulsions studied by contrast variation small-angle neutron scattering. Phys. Rev. E, 63, 61406-61423. 

R373 W. T. Heller, Small-Angle Neutron Scattering and Contrast Variation A Powerful Combination for Studying Biological Structures , Acta Crystal-logr.. Sect. D Biol. Crystallogr., [online computer file], 2010, D66, 1213. 

Small-angle X-ray scattering and other studies have not clarified the radial structure of these intriguing molecules (41,42) however, a recent study of the radial density profile by small-angle neutron scattering has provided a clearer picture of its structure (43). Lindner and co-workers have used contrast variation small angle neutron scattering to unequivocally show that these molecules have a density maximum at the center, and a density profile that decreases with radius. 

Abstract Partial structure functions and mean curvatures of a ternary amphiphilic system consisting of water, n-octane and nonionic amphiphile C12E5 with equal volume fraction of oil and water have been studied by means of small-angle neutron scattering (SANS). Isotopic contrast variation technique was used to obtain suitable scattering contrasts of oil and water. We observed that the cross partial structure functions, that arise from the correlation between water-surfactant or oil-surfactant, change sign when the temperature... 

Small-angle neutron scattering (SANS) is a unique tool to investigate the structure of mesoscopic molecular systems, e.g. polymeric macromolecules in solution or in the melt or mesoscopic aggregates (micelles, etc.) of small or macro-molecules. The substances involved usually contain a considerable amount of hydrogens, thereby allowing the application of the key technique of SANS, contrast variation. 

For the amphiphilic block copolymer in the non-polar selective solvent, the unpolar blocks form the corona, which provides solubilization and stabilization, while the polar or hydrophilic and functionalized blocks form the core, which is able to dissolve metal compounds due to coordination, followed by the nucleation and growth of metal particles upon reduction. Also the internal structure of block-copolymer micelles, as given by the size of core and corona and the density profile in each domain, has been carefully characterized by static and dynamic light scattering [146] and by small angle neutron scattering using contrast variation techniques [147], The micellar corona has many of the characteristics of a spherical polymer brush. 

Matsunaga, T., Endo, H., Takeda, M., and Shibayama, M. (2010) Microscopic structure analysis of day—poly(ethylene oxide) mixed solution in a flow fleld by contrast-variation small-angle neutron scattering. Macromolecules, 43, 5075-5082. 

Endo, H., Schwahn, D., and Colfen, (. (2004) On the role of block copolymer additives for calcium carbonate crystallization small angle neutron scattering investigation by applying contrast variation. Journal of Chemical Physics, 120, 9410-9423. 

Small-angle neutron scattering coupled with the contrast variation technique was used by Caponetti et al. [230] to study solutions of sodium perfluo-rooctaonate, sodium dodecanoate, and their mixture. Their data indicated the existence of mixed micelles having the same composition and a narrow size distribution. SANS data obtained by Berr and Jones [231] indicated that sodium perfluorooctanoate forms in water spherical micelles in which the fluorocarbon chains reside in a water-free core. 

Keywords Block copolymer micelles Contrast variation Equilibrium and nonequilibrium kinetics Morphology Small-angle neutron and X-ray scattering Time-resolved SAXS/SANS... 

Variation of contrast [46] is an important experimental technique in neutron small-angle scattering. Above and beyond size determination, it affords detailed insights into the internal structure of dissolved dendrimers and even permits the location of selected components of the molecule which have been previously labelled with deuterium. 

The extension of neutron contrast variation to the iron-protein ferritin (Section 4.2.7) illustrates polydispersity effects on small angle scattering [171,172]. For 60-80% iron-saturated ferritin, the matchpoint graph of /7(0) against % is not linear at low contrast differences Ap, and I 0) does not become zero (Fig. 19b). This is attributed to variable iron contents in different ferritin molecules. In 42%... 

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