Neutron flow-mapping : multiscale modelling opens a new experimental window.

Small-angle neutron scattering (SANS) has delivered significant insight into the rich and varied phenomena seen in the non-linear dynamics of entangled polymers. The lengthscales accessible by SANS are ideally matched to the strongly lengthscale-dependent relaxation in entangled polymers. This, in turn, has facilitated a detailed and challenging test for models of molecular rheology. Here, we review experimental techniques, along with the multiscale modelling required to predict these measurements. This approach has enriched our understanding of monodisperse linear polymers, model linear–linear blends and branched polymers. We also indicate potential future directions for this fruitful approach