Protection of nickel by self-assembled monolayers prepared in an aqueous self-emulsifying solution of a novel amphipathic organothiol.

Abstract

This report explored a novel amphiphilic organothiol and prepared self-assembled monolayers (SAMs) on Ni substance in the aqueous micellar solution of this amphiphilic organothiol. The as-prepared amphiphilic organothiol can self-emulsify and disperse in an aqueous solution to form a stable emulsion without any additional emulsifier. The experiment shows that the self-emulsifying solution remains stable after six months at room temperature. The resulting SAMs are characterized by electrochemical measurements, XPS, porosity tests, and neutral salt spray experiments. XPS results show that the as-prepared self-emulsifying organothiol can bond to the Ni surface by forming strong thiolate Ni-S bonds. The electrochemical measurements show that the inhibition efficiency (η) and surface coverage (θ) increase with the immersion time in the aqueous micellar solution, reaching the maximum value of about 90 min. Experiments prove that AGE-CA SAMs provided better protection for Ni substances and electroplated Ni film than the OT SAMs from the ethanol solution.