The structural perturbations that result from the interactions between
the anionic surfactant sodium dodecyl sulfate and the biopolymer gela
tin have been studied using small-angle neutron scattering. In particu
lar, contrast variation has been used to highlight the various compone
nts in the mixture. We discuss these data in terms of structural chang
es associated with the individual components and their interactions wi
th each other. The effect of ionic strength on these structures is als
o considered.