International
Tables for
Crystallography
Volume C
Mathematical, physical and chemical tables
Edited by E. Prince

International Tables for Crystallography (2006). Vol. C, ch. 2.9, p. 130

Section 2.9.7.3. Hydrogenous materials

G. S. Smitha and C. F. Majkrzakb

aManuel Lujan Jr Neutron Scattering Center, Los Alamos National Laboratory, Los Alamos, NM 87545, USA, and bNIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA

2.9.7.3. Hydrogenous materials

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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[link]) and Penfold & Thomas (1990[link]). Only one specific example will be given here.

Fig. 2.9.7.4[link] 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[link])]. Also shown in Fig. 2.9.7.4[link] 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.

[Figure 2.9.7.4]

Figure 2.9.7.4 | top | pdf |

(a) Measured neutron reflectivity for the Langmuir–Blodgett multilayer described in the text along with the fit. (b) Both corresponding neutron and X-ray scattering density profiles. The X-ray reflectivity is more sensitive to the high-Z barium in the head groups whereas the neutron reflectivity can distinguish mixing between adjacent hydrogenated and deuterated hydrocarbon tails [after Wiesler et al. (1995[link])].

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.
Russell, T. P. (1990). X-ray and neutron reflectivity for the investigation of polymers. Mater. Sci. Rep. 5, 171–271.
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.








































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