Self‐Assembled Layers of Alkanethiols on Copper for Protection Against Corrosion

Abstract

Self-assembled monolayers of alkanethiols CnH2, §(n = 6 ---18) adsorbed on the surface of a polycrystalline bulk Cu were constructed and characterized by x-ray photoelectron (XPS) and surface-enhanced Raman scattering (SERS) spectroscopy and contact angle and impedance measurements. The protection ability of the alkanethiol monolayers against Cu corrosion in an aerated 0.5M Na2SO4 solution was examined by impedance and polarization techniques. Results of XPS, SERS, and contact angle measurements showed that alkanethiols were chemisorbed on the Cu surface by the formation of strong bonds between Cu and S atoms following cleavage of a S-H bond and formed densely packed, water-repellent monolayers on the surface. The advancing contact angle of these monolayer films was comparable to that of alkanethiolate monolayers adsorbed at a vapor-deposited Cu on a Si wafer. However, sufficiently high protection abilities of the films against Cu corrosion were not obtained in 0.5M Na2SO4. A preliminary experiment demonstrated the formation of a promising protective film which was prepared on the Cu surface by modification of self-assembled ll-mercapto-l-undecanol monolayer with octyltrichlorosilane to form cross-linkages between the thiol molecules with siloxane bonds.

The Self Assembly of Superhydrophobic Copper Thiolate Films on Copper in Thiol Solutions

“…At low temperatures the thiol monolayers can protect copper against corrosion for a considerable time, at room temperature reaction is slowed but not halted as oxide grows beneath the thiol layer. [6,7] We noticed that if copper samples are allowed to stand in a solution of alkanethiol in ethanol for a long period they become covered with a whitish layer that, once dried, repels water very effectively. The extreme contact angle and water repellency indicates that this surface is superhydrophobic and therefore can be expected to have a combination of micro-or nano-scale roughness and hydrophobicity [8].…”

The Self Assembly of Superhydrophobic Copper Thiolate Films on Copper in Thiol Solutions

“…At low temperatures the thiol monolayers can protect copper against corrosion for a considerable time, at room temperature reaction is slowed but not halted as oxide grows beneath the thiol layer. [6,7] We noticed that if copper samples are allowed to stand in a solution of alkanethiol in ethanol for a long period they become covered with a whitish layer that, once dried, repels water very effectively. The extreme contact angle and water repellency indicates that this surface is superhydrophobic and therefore can be expected to have a combination of micro-or nano-scale roughness and hydrophobicity [8].…”

Dynamics of Alkyl Chains in Monolayer-Protected Au and Ag Clusters and Silver Thiolates: A Comprehensive Quasielastic Neutron Scattering Investigation

“…could be investigated. 1 They are excellent model systems, but one could use only reflection spectroscopies to study their properties. 2 In 1994 Brust et al reported the synthesis of monolayer-protected metal clusters (MPCs) by a two-phase synthesis.…”