pH-Triggered ionization of self-assembled monolayers investigated by in-situ surface plasmon resonance measurements

摘要

Self-assembled monolayers (SAMs) of 2-aminoethanethiolhydrochloride (AET) or 2-aminoethanethiol-hydrochloride (AHT) were formed on gold substrate. Deprotonation and reprotonation of SAMs of AET and AHT on gold substrate were investigated by using time-resolved surface plasmon resonance (SPR) measurements. The changes of the terminal functional groups from -NH_3~+Cl~- to -NH_2 (vice versa) via the HO and NaOH treatment were successfully detected, based on the fact that the initially formed AET and AHT SAMs were assumed to be a zwitterion-like species, -NH_3~+Cl~-.