Self-diffusion coefficient distributions in solutions containing hydrophobically modified water-soluble polymers and surfactants

The self-diffusion coefficient distribution, obtained from an inverse Laplace transform of the pulsed-gradient spin-echo nuclear magnetic resonance attenuation function, has been studied as a function of both associative polymer and surfactant concentration. Compared to the parent homopolymer, the associative polymer exhibited a much wider distribution of self-diffusion coefficients, which narrows with surfactant concentration. When the surfactant concentration reaches the saturation level for the polymer, the width of the distributions of the parent homopolymer and associative polymer become identical. The structural basis for these observations is discussed.