Paramagnetic enhanced spin–lattice relaxation in micellar solutions

Abstract

Proton spin–lattice relaxation rates have been measured for micellar solutions of SDS, DTAB and C₁₂ E₆ in D₂O as a function of the concentration of added salts of Cr³⁺, Co²⁺, Ni²⁺ and Cu²⁺. The data are interpreted in terms of a simple two site model in which protons at the surface of a micelle are assumed to relax at a rate which depends on the paramagnetic ion concentration according to a Langmuir-type equation. The probabilities of finding hydrocarbon segments at the surface have been determined.