Langmuir, Vol.12, No.12, 2884-2893, 1996
A Self-Diffusion Study of the Complex Formed by Sodium Dodecyl-Sulfate and Gelatin in Aqueous-Solutions
The diffusion behavior of both the anionic surfactant sodium dodecyl sulfate and gelatin have been studied by pulsed-gradient spin-echo NMR spectroscopy (PGSE-NMR) in aqueous solutions at 44 degrees C, well above the setting temperature. The studies were made as a function of both surfactant and gelatin concentration for two different lime-processed gelatin samples : one the standard photographic material, the other a fractionated sample. Above c*, the fractionated and standard gelatins exhibit different behavior in both the presence and absence of SDS, Adding SDS slows the diffusion of the gelatin, which passes through a minimum with increasing surfactant concentration. The diffusion data are compared to light scattering, small-angle neutron scattering and viscosity data from similar systems. An isotherm characterizing the SDS binding to the gelatin has been derived from the self-diffusion data.
Keywords:NUCLEAR MAGNETIC-RESONANCE;ANIONIC SURFACTANTS;NEUTRON-SCATTERING;MICELLES;CONFORMATION;CHAINS;LIGHT