Electrochemistry of 2-dimethylaminoethanethiol SAM on gold electrode: Interaction with SWCNT-poly(m-aminobenzene sulphonic acid), electric field-induced protonation–deprotonation, and surface pKa

Electrochemical behaviour of self-assembled monolayer of 2-dimethylaminoethanethiol (DMAET) on gold electrode, with and without integration with SWCNT-poly(m-aminobenzene sulphonic acid) (SWCNT-PABS) has been probed. It is proved that the so-called electric fieldinduced protonation–deprotonation process, hitherto observed for the –COOH terminated SAMs, is also observed for the –N(H)+(CH3)2 terminated. The surface pKa of DMAET was estimated as 7.6, smaller than its solution pKa of 10.8. It is also shown that SWCNT-PABS is irreversibly attached to the DMAET SAM.