Scattering of radiation is a powerful analytical tool to monitor the structure and dynamics of a broad range of soft materials, including polymers, colloids, and biomolecules. Many polymer scientists are probably familiar with the use of a Zimm plot to measure the radius of gyration and molecular weight of a polymer in solution by light scattering. Such measurements require that the polymer be in a dilute solution and the solution be transparent to light. Similarly, analysis of the angular dependence and energy of the scattering of neutrons by polymers provides a tool to monitor more detailed structure or dynamics of the macromolecule in a broad range of environments, including melts and concentrated solutions. This capability to monitor the macromolecular chain in concentrated mixtures is the result of the ability to introduce contrast in neutron scattering by the selective deuteration of a polymer chain and the penetrating power of the neutron. Thus, deuterated polymer chains that are molecularly dispersed in a matrix of identical protonated chains will produce a scattering pattern that correlates to the structure of that deuterated chain.
The ability to tune contrast by selective deuteration combined with the fact that the wavelength of cold neutrons probe the correct length scales to monitor polymers from individual segments up to the entire coils makes neutron scattering a very powerful technique to examine soft materials. However, many polymer scientists are unaware or the range of problems that can be examined using neutron scattering. In this issue, we bring together leading experts in the field to present examples of how neutron scattering can be used to understand the physics of polymeric systems. We have included articles that describe the use of small angle neutron scattering, neutron reflectivity and incoherent neutron scattering to examine the structure, dynamics and thermodynamics of polymeric systems. Some of the papers are reviews, some present current research in polymer physics, and some are targeted to provide the reader with an in depth description of the neutron scattering technique. It is the editors hope that they will all be viewed by the curious reader as examples of how neutron scattering can be used to study polymeric systems, providing insight into the information that can be garnered from carefully planned neutron scattering experiments. When we began planning this special issue, it was our goal to create a valuable tool to the polymer community, a reference for the types of problems and physical parameters that can be understood with neutron scattering techniques. With the help of all the authors in this issue, we believe that we have succeeded; hopefully you will agree.