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Neutron Studies of Polymers

The possibility to contrast given fractions of a polymer system at a cost of a low enthalpy difference is responsible for the success of the neutron method. This approach is especially useful for polymers as compared to colloids or simple liquids, because of the significative intra- and intermolecular correlations. In this respect, the pseudo diblock copolymer constitutes one of the best test molecule of homogeneous polymer system. A review is given of main results: Polymer size in melts, true backbone conformation and universal constants related to polymer structures. Effects of mechanical stress, or mesogenic order have been revealed. Neutron spinecho experiments have given characteristic dispersion relations of intra- and inter-polymer diffusive motions. The labelling method is however more powerful than first realized. The amplitude associated with a polymer structure at an interface has been obtained directly (as in ellipsometry) with the use of contrast variation. Such structures are currently investigated by neutron reflectivity. Latest developments are found in the use of spin polarized targets, from which important cross correlations are derived.