AN ELECTROKINETIC STUDY OF LANGMUIR-BLODGETT-FILM COATED SURFACES

The electrokinetics of solid surfaces coated with one or more layers of cationic and anionic Langmuir-Blodgett (LB) deposited amphiphiles has been measured as a function of pH. The pH of neutralization of the film was found to be dependent on the level of counterion binding to the deposited lipid, solution ionic strength conditions and the magnitude of the charge on the base substrate. Compilation of results for the electrokinetics of cationic lipid molecules on silica surfaces indicates that both lipid loss and regulation of counterion binding occur as a function of pH. Similarly, casting multiple LB layers of charged molecules as a means of negating substrate charge as a function of pH was found to yield results much like the single-layer film surfaces.