Micellization of sodium dodecyl sulfonate and Triton X-100 in polyacrylamide water solution studied by H-1 NMR relaxation and two-dimensional nuclearoverhauser enhancement spectroscopy

Micellization of Triton X-100 (TX-100) and sodium dodecyl sulfonate (SDSN) in the presence of partially hydrolyzed polyacrylamide (PAAM) was studied b y H-1 NMR spin-spin and spin-lattice relaxation. Relaxation experiment resu lts show that TS-100 behaves differently from SDSN in micellization in the presence of PAAM. PAAM causes a decrease in the critical micellar concentra tion of SDSN, while it has no influence on the critical micellar concentrat ion of TX-100. The lack of cross peaks between protons of PAAM and those of TX-100 and SDSN in the 2D nuclear Overhauser enhancement spectroscopy (NOE SEY) spectra confirms self-aggregation of TX-100 and SDSN in the presence o f PAAM. The identity of each of the corresponding interproton distances of TX-100 with and without the addition of PAAM further confirms the formation of normal TX-100 micelles in the presence of PAAM. Besides, the distances between protons on the hydrophilic and hydrophobic chains in TX-100 micelle s, calculated from the 2D NOESY spectra, are remarkably shorter than those for an extended hydrophilic poly(oxyethylene) chain. This implies that the hydrophilic chain is curled upon micellization.