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Modification and Patterning of Self‐Assembled Monolayers Using Electrogenerated Etchants and Homogeneous Scavenging Reactions in a Scanning Electrochemical Microscope
Author(s) -
Vaske Britta,
Schaube Maximilian,
Meiners Frank,
Ross Jan Henning,
Christoffers Jens,
Wittstock Gunther
Publication year - 2021
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.202100718
Subject(s) - scanning electrochemical microscopy , monolayer , chemistry , electrochemistry , substrate (aquarium) , diffusion , microelectrode , self assembled monolayer , scanning electron microscope , chemical engineering , analytical chemistry (journal) , materials science , nanotechnology , organic chemistry , electrode , oceanography , physics , composite material , geology , engineering , thermodynamics
Self‐assembled monolayers (SAMs) of oligoethylene glycol (OEG)‐terminated alkanethiolates on gold, which are used to control protein adsorption and cell adhesion, were patterned by reaction with Br 2 /HOBr electrogenerated at a microelectrode of a scanning electrochemical microscope (SECM). The spreading of the Br 2 diffusion layers was limited by a homogeneous reaction with cystamine or L‐cystine as scavengers. The influence of process parameters on the patterning process was explored by simulation and combinatorial experiments. The experimental determination of pattern sizes from SECM feedback images was verified by scanning force microscopy. The simulation considered the local Br 2 formation as well as Br 2 consumption in the reaction with the OEG SAM, by reduction at the gold substrate, and by the homogeneous scavenging reaction. It used experimentally determined diffusion coefficients and rate constants of the scavenging reaction. and Experiments and simulation confirmed the existence of regions in the parameter space, in which the patterning process is robust against small variation of the parameters working distance, pulse time and scavenger excess.