ALKANETHIOL MONOLAYERS AND ALKANETHIOL-VERTICAL-BAR-PHOSPHOLIPID BILAYERS SUPPORTED BY MERCURY - AN ELECTROCHEMICAL CHARACTERIZATION

The preparation of self-assembled alkanethiol monolayers and alkanethi ol \ phospholipid bilayers on a home-made hanging mercury drop electro de is described. Two different experimental procedures are used to pre pare alkanethiol monolayers on mercury. Once a stable thiol monolayer is obtained on the mercury electrode, formation of the bilayer is simp le and highly reproducible. The bilayers consist of a thiol monolayer anchored to mercury via the sulfur atom, with a second phospholipid mo nolayer on top of it. Monolayers and bilayers are characterized electr ochemically by measuring capacitance and resistance. Both thiol-coated and thiol I lipid-coated mercury electrodes present a compact and wel l-ordered structure, absence of defects and high reproducibility. The permeability of these films to compounds with different degrees of lip ophilicity is examined. The results point to a high impermeability of self-assembled alkanethiol monolayers and mixed alkanethiol I phosphol ipid bilayers supported by mercury to lipophilic compounds. (C) 1998 E lsevier Science S.A. All rights reserved.