ELECTROCHEMICAL AND STRUCTURAL STUDY OF REDOX-ACTIVE SELF-ASSEMBLED MONOLAYERS

Abstract

WE USED SELF-ASSEMBLED MONOLAYERS (SAMS) OF N-ALKANETHIOLATES FUNCTIONALIZED WITH REDOX-ACTIVE FERROCENE (FC) GROUP AS MODEL SYSTEMS TO STUDY THEIR REDOX BEHAVIOR AS A FUNCTION OF SUPRAMOLECULAR STRUCTURE DETERMINED BY A COMBINATION OF COMPLIMENTARY CHARACTERIZATION TECHNIQUES, E.G., SPECTROSCOPY, SCANNING TUNNELING MICROSCOPY, AND THEORETICALLY CONFIRMED BY MOLECULAR DYNAMICS. THIS DETAILED UNDERSTANDING OF SAM STRUCTURES MADE IT POSSIBLE TO ADDRESS LONG STANDING ISSUES IN THE INTERPRETATION OF ELECTROCHEMICAL BEHAVIOR OF REDOX-ACTIVE SAMS AT SOLID-LIQUID INTERFACE. THE COUPLING BETWEEN FC UNITS AND ELECTRODE WAS CONTROLLED BY VARYING THE LENGTH OF THE ALKYL CHAIN, AND ELECTROSTATIC EFFECTS AT SAM/ELECTROLYTE INTERFACE WERE CONTROLLED BY VARYING POSITIONS OF FC UNITS IN THE SAMS. WE PROPOSE MODELS TO DESCRIBE REDOX BEHAVIOR OF FC-SAMS IN TERMS OF INTERMOLECULAR INTERACTIONS. THE MODELS ALSO ACCOUNTS FOR THE ROLE OF DEFECTS INDUCED BY IMPURITIES AND DEFECTS IN THE ELECTRODE MATERIALS.