Design of an Organic Ultramicroelectrode Array. Potential Use of Microstructures of Binary Langmuir–Blodgett Monolayers of Totally π-Conjugated Electroactive and Electroinactive Amphiphiles

Mixed monolayers of totally π-conjugated electroactive compounds, 1-methyl-4-[2-[4-[2-(4-quinolyl)vinyl]phenyl]vinyl]quinolinium perchlorate (1) and 1-methyl-4-[2-[4-[2-(4-pyridyl)vinyl]phenyl]vinyl]pyridinium perchlorate (2) and those of compound 1 and palmitic acid (PA) were formed on a 0.1 M KClO4 aqueous solution. Surface pressure area isotherms and fluorescence microscopic observations suggest that mixtures of compounds 1 and 2 form homogeneous mixed monolayers, but those of 1 and PA are phase-separated in the mixed monolayers. These monolayers were transferred to gold by using the Langmuir–Blodgett technique and then in situ electrochemical characterization was conducted. Cyclic voltammograms of the mixed monolayers of 1-2 and 1-PA on gold indicate rectified transmembrane electron transfer through the monolayer of 1 in the mixed monolayers to hexacyanoferrate(II) in solution. Potential-step chronocoulometric responses have revealed that the monolayer of 1 in the mixed LB monolayer of 1-2 acts as an ...