THE BEHAVIOR OF ORGANIC COUNTERIONS IN THE MICELLE OF ALKYLAMMONIUM DECYLSULFONATES

The behavior of organic counterions in the micellar state was studied for alkylammonium decylsulfonate systems by C-13 NMR and conductivity measurements. The chemical shifts of C2'-C5' carbon atoms in n-butylammonium and n-pentylammonium ions showed a downfield shift of 0.2-0.6 ppm in comparison with those of the corresponding chlorides. Moreover, the spin-lattice relaxation time T1 of the decylsulfonate ions had irregularities caused by collision between the decyl chains and the terminal methyl group of the counterions when the counterions were n-butylammonium and n-pentylammonium ions. The conductivity measurements indicated that the degree of dissociation of the counterions decreases with increasing counterion chain length. These facts can be explained by the long-chain counterions forming a mixed micelle with decylsulfonate ions while the short ones do not.