NMR study of polymer surfactant interaction in the system HPMC/SDS/water

The interaction between the nonionic water soluble polysaccharide hydroxypropylmethyl cellulose (HPMC) and the low molecular weight amphiphile sodiumdodecyl sulphate (SDS) has been studied by NMR¹H-chemical shift measurements and by self-diffusion NMR measurements. The polymer concentration has been kept sufficiently dilute to avoid coil overlap and the SDS composition range goes from zero up to well above the normal CMC point. Although a different fraction was used, the present results agree well with previous results for the same system obtained by techniques other than NMR and show very clear break points that can be related to the polymer surfactant interaction. Furthermore, it can be inferred from the chemical shift measurements that the structure of the micellar clusters are similar whether polymer is present or not. From a combination of chemical shift and self diffusion measurements it is also found that neither the size nor the shape of the clusters seem to change significantly in the composition interval investigated.