International
Tables for Crystallography Volume C Mathematical, physical and chemical tables Edited by E. Prince © International Union of Crystallography 2006 |
International Tables for Crystallography (2006). Vol. C. ch. 2.9, p. 130
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There are a substantial number of applications of neutron reflectometry in the study of hydrogenous films and multilayers, including diblock copolymer, surfactant, Langmuir–Blodgett, self-assembled monolayer, and lipid bilayer films. Reviews of the extensive research that has already been done have been written by Russell (1990) and Penfold & Thomas (1990). Only one specific example will be given here.
Fig. 2.9.7.4 shows neutron reflectivity data and the corresponding density profile for a Langmuir–Blodgett film composed of alternating bilayers of deuterated and hydrogenated stearic acid [after Wiesler, Feigin, Majkrzak, Ankner, Berzina & Troitsky (1995)]. Also shown in Fig. 2.9.7.4 is the scattering-density profile for the same sample as seen by X-rays. It is obvious that the X-rays are more sensitive to the high-Z barium in the head group, whereas the neutrons are especially good at distinguishing the degree of mixing between adjacent hydrogenated and deuterated hydrocarbon tails. This is a good example of the complementary nature of neutron and X-ray reflectivities.
References
Penfold, J. & Thomas, R. K. (1990). The application of specular reflection of neutrons to the study of surfaces and interfaces. J. Phys. Condens. Matter, 2, 1369–1412.Google ScholarRussell, T. P. (1990). X-ray and neutron reflectivity for the investigation of polymers. Mater. Sci. Rep. 5, 171–271.Google Scholar
Wiesler, D. G., Feigin, L. A., Majkrzak, C. F., Ankner, J. F., Berzina, T. S. & Troitsky, V. I. (1995). Neutron and X-ray reflectivity study of Ba salts of alternating bilayers of deuterated and hydrogenated stearic acid. Thin Solid Films, 266, 69–77.Google Scholar