Effect of ionic binding on the self-diffusion of anionic dendrimers and hydrophilic polymers in aqueous systems as studied by pulsed gradient NMR techniques

Pulsed gradient NMR techniques including diffusion-ordered NMR spectroscopy have been used to study the self-diffusion of three carboxylated dendrimers in aqueous solutions of neutral poly(vinyl alcohol) (PVA) and of cationic poly(allyl amine) (PAAm). The ionic interaction between the cationic PAAm network and the anionic dendrimers had the most significant effect on the diffusion of the dendrimers in the system. The self-diffusion coefficients of the dendrimers in PAAm were an order of magnitude lower than in PVA and more widely distributed, and the activation energy for the displacement of the dendrimers in PAAm was higher than that in PVA. The effects of the dendrimer size, polymer concentration, and temperature on the diffusion of the dendrimers have also been studied.