Alkanethiol Reductive Desorption from Self-Assembled Monolayers on Gold, Platinum, and Palladium Substrates

Abstract

The reductive desorption of n-alkanethiolate (RS-) self-assembled monolayers (SAMs) on gold, platinum, and palladium substrates was investigated. The kinetics of this process were too slow to measure directly in the case of RS-Pt and RS-Pd SAMs. Thus, the faradaic response of potassium ferricyanide after partial or complete desorption was determined and used to quantify the relative electrochemically accessible surface area. Both the type of underlying metal substrate and the chain length of the n-alkanethiol were varied. The relative alkanethiol binding affinity and effective kinetics of binding for each of the substrates were discussed in light of these observations.

Electrochemistry of redox-active self-assembled monolayers

“…XPS data reveal a complex palladium sulfide interphase that appears to enhance the SAM stability against corrosion [389,391]. The potential of reductive desorption of alkane thiols on Pd does not change significantly with the hydrocarbon chain length, unlike Au, Ag, Pt, and Ni which do not have an analogous metal-sulfide interphase [392]. …”

Self-assembled monolayers of l-cysteine on palladium electrodes

“…3a shows that the reductive desorption peak of L-cysteine molecules (b) did not appear at negative potential scans. This is due to the slow kinetic process at the palladium electrode [17,18]. Therefore, it was not possible to determine the surface coverage using reductive desorption in KOH solution.…”

Electrochemical desorption of self-assembled monolayers and its applications in surface chemistry and cell biology

“…Similar to desorbing thiols from Au substrates, ECD is also used to desorb other types of molecules like PLL-PEG and DNA [92,93]. Alternative substrates like platinum and palladium have been tested [63,94]. Exploring new molecules or substrates for desorption would extend our library of dynamically controllable surface chemistry.…”