SYNTHETIC BILAYER ADSORPTION ONTO POLYSTYRENE MICROSPHERES

Small and large vesicles prepared from dihexadecyl phosphate (DHP) and dioctadecyldimethylammonium chloride (DODAC) or bromide (DODAB) interact with oppositely charged polystyrene microspheres forming bilayer covered latices. Adsorption isotherms are of the Langmuir type, and for the three amphiphiles studied the limiting areas at the polystyrene/water interface are consistent with bilayer deposition. At limiting adsorption, electrokinetic properties of the covered particles were very similar to those of the vesicles. An innovative procedure for detecting bilayer adsorption based on determination of the mean z-average diameter of particles in the latex/vesicle mixtures as a function of amphiphile concentration is described.