Interaction of benzene with micelles and bilayers
The organic phase-aqueous phase partition coefficient of benzene was directly measured into nonpolar isotropic liquids, detergent micelles, and phospholipid bilayers above and below their gel-to-liquid crystalline transition temperature. From these data we conclude that benzene is, on the average, situated in a nonpolar environment. The relatively small difference in the free energy of transfer of benzene from benzene to any of these solvents in their liquid phases is almost entirely accounted for by a positive enthalpy of transfer. Below the transition temperature the entropy of transfer contributes to the more positive free energy of transfer. We also conclude that the Laplace pressure and possible water penetration into the nonpolar phases do not significantly influence the partition coefficient Attempts to use ultraviolet spectroscopy to determine the location of benzene in micelles were unsuccessful because of the fact that the numbers obtained for the effective dielectric constant are not single valued. © 1982 American Chemical Society.
