The effect of electrostatic fields on an oligo(ethylene glycol) terminated alkanethiol self-assembled monolayer

Static energy minimization and Monte Carlo simulation are used to study the effect of external electrostatic fields on the structure of a self-assembled monolayer (SAM) formed by methoxytri(ethylene glycol) terminated alkanethiol molecules. It is found that fields of the order of 1 V Å−1 in strength can substantially change the equilibrium configuration of the SAM, making the oxygen atoms of the terminal methoxy groups buried or exposed depending on the field polarity, which is qualitatively similar to what was found in our previous ab initio calculations with a single molecule. This finding implies a potential possibility of developing SAM-coated surfaces with electrically controlled (switchable) properties.