Small-angle neutron scattering studies of sodium dodecyl sulfate interactions with gelatin .2. Effect of temperature and pH

Structural perturbations and interactions between the anionic surfactant sodium dodecyl sulfate (SDS) and the biopolymer and polyampholyte gelatin, have been studied using small-angle neutron scattering. The effects of temperature and changes in pH have been investigated. Although the physical properties of the systems change dramatically with temperature, from a gel at 25 degrees C to a fluid at 65 degrees C, the effects on the structure over the dimensions probed by small-angle neutron scattering are rather weak. Changes in pH, which alter the net charge of the gelatin, lead to dramatic changes in the scattering for pure gelatin solutions and for surfactant-gelatin mixtures.