Applications of neutron reflectometry

Neutron reflectometry has been applied to three classes of polymer systems (1) polymers adsorbed from solution to an interface (generally the solid-liquid interface) (2) solid polymer films and (3) polymers spread as monolayers. Russell [56] has surveyed results up to mid-1990, and so attention here is concentrated on results obtained since that time. 

3 Polymer monolayers. Polymeric spread films at the air-water interface are examples of polymers in pseudo-two-dimensional situations. The nature of such films is germane to the preparation of Langmuir-Blodgett films. 

For a polymer film containing water then the variation of scattering-length density normal to the surface is  

This chapter has been deliberately confined to the applications of neutron scattering and neutron reflectometry to polymer systems. Many of the scattering laws and equations are directly transferable to X-ray scattering and reflectometry (with proper correction for the more prevalent absorption effects) however, the power and flexibility available by deuterium labelling is not at hand for X-rays, and for this reason attention has been restricted to neutron scattering. Even with this restriction it has been impossible to discuss properly all the applications of neutron scattering and neutron reflectometry in the available space. It is abundantly clear that more people are using the 

Wignall (1987). Encyclopedia of Polymer Science and Engineering, Vol. 10, 2nd edn, Wiley, New York. 

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In the last 10-15 years, neutron reflectometry has been developed into a powerful technique for the study of surface and interfacial structure, and has been extensively applied to the study of surfactant and polymer adsorption and to determine the structure of a variety of thin films [14, 16]. Neutron reflectivity is particularly powerful in the study of organic systems, in that hydrogen/deu-terium isotopic substitution can be used to manipulate the refractive index distribution without substantially altering the chemistry. Hence, specific components can be made visible or invisible by refractive index matching. This has, for example, been extensively exploited in studying surfactant adsorption at the air-solution interface [17]. In this chapter, we focus on the application of neutron reflectometry to probe surfactant adsorption at the solid-solution interface. 

Attention will be focused here on the use of small-angle neutron scattering (SANS) in polymer systems and the application of neutron reflectometry (NR) to polymer surfaces and interfaces. SANS has been used to investigate mole-... 

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