SANS contrast variation on a dendrimer host-guest complex

Small-angle neutron scattering (SANS) technique was used to study the configurational changes in an oligoethyleneoxy-functionalized poly(propyleneimine) dendrimer (host) when forming complexes with rose bengal (guest). Guinier fits to the scattering data recorded at max. contrast indicated a decrease in the radius of gyration (Rg = 2.2 nm) of the dendritic system after complex formation (Rg = 1.9 nm). The structure of the host system must fluctuate strongly with the endgroups revealing a significant amt. of backfolding. Moreover, SANS data indicated clear evidence for changes in the macromol