MEASUREMENT OF SINGLE CHAIN NEUTRON-SCATTERING IN CONCENTRATED POLYMER-SOLUTIONS

For some time there have been measurements of single-chain form factors for small-angle neutron scattering (SANS) in bulk polymers and in concentrated solutions. These were done by mixing a fraction of completely deuterated polymer with the normal polymer. Until recently, it was believed that these experiments had to be performed using a small fraction of deuterated polymer to avoid interchain interference effects. However, the work of Williams et al. has shown that these experiments are better if one uses large fractions of marked polymer and determines both the single chain and interference contributions to the SANS cross section. The authors generalize the technique of Williams et al. somewhat and apply it to the measurement of the radius of gyration of polyisoprene in the bulk.