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Electrochemical formation of alkanethiolate monolayers at gold

Conference ·
OSTI ID:143130
; ;  [1]
  1. Iowa State Univ., Ames, Iowa (United States)

Self-assembled monolayers have been used as attractive model systems in studies of reactivities at organic interfaces. This paper presents a new method for the preparation of thiolate monolayers that allows enhanced control of formation via reaction thermodynamics. Thiolate monolayers can be electrochemically prepared by a one-electron oxidative deposition (Au+X(CH{sub 2}){sub n}S{sup {minus}} {yields} X(CH{sub 2}){sub n}SAu+e{sup {minus}}). These electrodeposited monolayers have been characterized by infrared reflection absorbance spectroscopy, contact angle, and scanning tunneling, and atomic force microscopics and are structurally comparable to the corresponding self-assembled monolayers. Manipulation of the redox equilibrium by adjustment of the applied voltage results in monolayers with variable, reproducible coverage. Results from experiments using several different thiolates (i.e., n = 1.15 for X=CH{sub 3}, n=2 for X=CF{sub 3}(CF{sub 2}){sub 7}, n = 1, 2, for X =COOH, and n = 2,3 for X =OH) and electrolyte solutions will be discussed with regard to equilibrium and electron transfer kinetic effects on the voltammetric wave shape and peak position. The relationship between voltammetric wave shape and reaction thermodynamics will also be examined in the context of both the electrochemical deposition and desorption data.

OSTI ID:
143130
Report Number(s):
CONF-930304--
Country of Publication:
United States
Language:
English