Self-assembly mechanism of thiol, dithiol, dithiocarboxylic acid, disulfide and diselenide on gold: An electrochemical impedance study

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Abstract

The self-assembly mechanism of normal aliphatic thiol (RSH), disulfide (RSSR), diselenide (RSeSeR), dithiol (R(SH)2) and dithiocarboxylic acid (RS2H) onto a gold surface was studied in real time by electrochemical impedance spectroscopy (EIS). The different stages of adsorption could be clearly followed from the interfacial capacitance variation. An initial very fast adsorption, varying from a few seconds to several minutes depending on concentration, is the major adsorption step. This fast step is followed by long-term additional adsorption and self-assembled monolayer (SAM) consolidation. However, an intermediate step, probably due to transformation from the initial physisorbed state to the self-assembled state, could be identified with RSH and R(SH)2. An intermediate rearrangement of RS2H molecules after their initial diffusion controlled Langmuir (DCL) adsorption through the thiol functional group was also recognized. Initial adsorption of RSH and R(SH)2 followed either purely diffusion controlled or DCL kinetics for a very short time. Their continuing fast adsorption followed DCL kinetics. The fast adsorption step of RSSR and RSeSeR also followed the same mechanism. The findings made with EIS on the SAM organization were analyzed by polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS). The R(SH)2 based SAMs had comparatively poor organization.

Original languageEnglish
Pages (from-to)16648-16656
Number of pages9
JournalPhysical Chemistry Chemical Physics
Volume15
Issue number39
DOIs
Publication statusPublished - 21 Oct 2013

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disulfides
Sulfhydryl Compounds
thiols
Gold
Disulfides
Self assembly
self assembly
impedance
gold
Adsorption
acids
adsorption
Acids
Self assembled monolayers
Electrochemical impedance spectroscopy
polarization modulation
Kinetics
dithiol
infrared reflection
consolidation

Cite this

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title = "Self-assembly mechanism of thiol, dithiol, dithiocarboxylic acid, disulfide and diselenide on gold: An electrochemical impedance study",
abstract = "The self-assembly mechanism of normal aliphatic thiol (RSH), disulfide (RSSR), diselenide (RSeSeR), dithiol (R(SH)2) and dithiocarboxylic acid (RS2H) onto a gold surface was studied in real time by electrochemical impedance spectroscopy (EIS). The different stages of adsorption could be clearly followed from the interfacial capacitance variation. An initial very fast adsorption, varying from a few seconds to several minutes depending on concentration, is the major adsorption step. This fast step is followed by long-term additional adsorption and self-assembled monolayer (SAM) consolidation. However, an intermediate step, probably due to transformation from the initial physisorbed state to the self-assembled state, could be identified with RSH and R(SH)2. An intermediate rearrangement of RS2H molecules after their initial diffusion controlled Langmuir (DCL) adsorption through the thiol functional group was also recognized. Initial adsorption of RSH and R(SH)2 followed either purely diffusion controlled or DCL kinetics for a very short time. Their continuing fast adsorption followed DCL kinetics. The fast adsorption step of RSSR and RSeSeR also followed the same mechanism. The findings made with EIS on the SAM organization were analyzed by polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS). The R(SH)2 based SAMs had comparatively poor organization.",
author = "{Vijayan Sobhana}, Dilimon and Sundar Rajalingam and J. Delhalle and Z. Mekhalif",
year = "2013",
month = "10",
day = "21",
doi = "10.1039/c3cp51804c",
language = "English",
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pages = "16648--16656",
journal = "Physical chemistry chemical physics : PCCP",
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publisher = "Royal Society of Chemistry",
number = "39",

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T1 - Self-assembly mechanism of thiol, dithiol, dithiocarboxylic acid, disulfide and diselenide on gold

T2 - An electrochemical impedance study

AU - Vijayan Sobhana, Dilimon

AU - Rajalingam, Sundar

AU - Delhalle, J.

AU - Mekhalif, Z.

PY - 2013/10/21

Y1 - 2013/10/21

N2 - The self-assembly mechanism of normal aliphatic thiol (RSH), disulfide (RSSR), diselenide (RSeSeR), dithiol (R(SH)2) and dithiocarboxylic acid (RS2H) onto a gold surface was studied in real time by electrochemical impedance spectroscopy (EIS). The different stages of adsorption could be clearly followed from the interfacial capacitance variation. An initial very fast adsorption, varying from a few seconds to several minutes depending on concentration, is the major adsorption step. This fast step is followed by long-term additional adsorption and self-assembled monolayer (SAM) consolidation. However, an intermediate step, probably due to transformation from the initial physisorbed state to the self-assembled state, could be identified with RSH and R(SH)2. An intermediate rearrangement of RS2H molecules after their initial diffusion controlled Langmuir (DCL) adsorption through the thiol functional group was also recognized. Initial adsorption of RSH and R(SH)2 followed either purely diffusion controlled or DCL kinetics for a very short time. Their continuing fast adsorption followed DCL kinetics. The fast adsorption step of RSSR and RSeSeR also followed the same mechanism. The findings made with EIS on the SAM organization were analyzed by polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS). The R(SH)2 based SAMs had comparatively poor organization.

AB - The self-assembly mechanism of normal aliphatic thiol (RSH), disulfide (RSSR), diselenide (RSeSeR), dithiol (R(SH)2) and dithiocarboxylic acid (RS2H) onto a gold surface was studied in real time by electrochemical impedance spectroscopy (EIS). The different stages of adsorption could be clearly followed from the interfacial capacitance variation. An initial very fast adsorption, varying from a few seconds to several minutes depending on concentration, is the major adsorption step. This fast step is followed by long-term additional adsorption and self-assembled monolayer (SAM) consolidation. However, an intermediate step, probably due to transformation from the initial physisorbed state to the self-assembled state, could be identified with RSH and R(SH)2. An intermediate rearrangement of RS2H molecules after their initial diffusion controlled Langmuir (DCL) adsorption through the thiol functional group was also recognized. Initial adsorption of RSH and R(SH)2 followed either purely diffusion controlled or DCL kinetics for a very short time. Their continuing fast adsorption followed DCL kinetics. The fast adsorption step of RSSR and RSeSeR also followed the same mechanism. The findings made with EIS on the SAM organization were analyzed by polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS). The R(SH)2 based SAMs had comparatively poor organization.

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