Effect of acidity on the formation of solvent-free lipid bilayers

Glasses with hydrophobized surface are used to form dry bilayer lipid membranes (BLM). The contact angle on the silaned glass plates reaches 125 degrees. Partitions of this kind, as opposed to polymer films, make a system more resistant to heat oscillations and mechanical perturbations generated when studying membranes properties. The specific capacitance of BLM (0.86 +/- 0.04 mu F cm(-2)) testifies to the solvent absence in the bilayer. The dramatic drop of the capacitance (area) of the dry membranes with increasing pH is caused by a greater adsorption of lipid molecules on the hydrophobic substrate, which is probably due to changing conformation of their polar head.