The interaction of n-octanol with black lipid bilayer membranes

The electrical capacities of black lipid films formed from monoolein + n-hexadecane and monoolein + squalane (or squalene) solutions have been measured in the presence of various concentrations of n-octanol. In addition, partition coefficients for n-octanol between n-hexadecane and 0.1 M NaCl, dielectric constants for octanol-hexadecane mixtures and the interfacial tension of films and film-forming lipid solutions against the aqueous phases have been determined. It is concluded that in "solvent-free" bilayers the octanol is unlikely to have changed the bilayer thickness by more than about 1 A. The bilayer tension, on the other hand, increases appreciably in the presence of octanol.