A model of the molecular motional state of unsonicated lipid bilayers is derived from proton magnetic resonance (pmr) line width considerations. The pmr line widths of both chain protons and the protons of methyl groups are calculated using a computer program based on Anderson's stochastic theory of resonance line widths. Spin-lattice relaxation phenomena observed for protons in lipid bilayers are also explained in terms of the same motional model. Finally, the effects of sample sonication on the pmr line widths are discussed in the light of stochastic relaxation results. Amphiphilic molecules, e.g., soaps, lecithins, or i surfactants, generally, can form bilayer structures in water resembling those found in cell membranes.3-8 Recently many biologically motivated studies of these lipid bilayers9-20 have tried to determine the degree of molecular mobility in the interior and at the surface of the bilayer. Although proton magnetic resonance (24) R. Kubo and K. Tomita, /.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.