Chemical Modification of an Alkanethiol Self‐Assembled Layer to Prevent Corrosion of Copper

A protective film consisting of an ultrathin, closely packed, and highly water-repellent two-dimensional polymer monolayer was prepared by modification of an 11-mercapto-1-undecanol (MUO) self-assembled monolayer adsorbed on copper with 1,2-bis(trichlorosilyl)ethane (BTCSE) and subsequently with octadecyltrichlorosilane (C{sub 18}TCS). In order to provide regularly arranged C{sub 18} alkyl chains and two-dimensional cross-linkages within the layer, the BTCSE-modified MUO monolayer was treated with C{sub 18}TCS at low concentrations for many hours. The protective efficiency of the MUO monolayer modified with BTCSE and with 5 {times} 10{sup {minus}4} M C{sub 18}TCS for 24 h for copper corrosion in an aerated 0.5 M Na{sub 2}SO{sub 4} was markedly high, 98.9%. The doubly modified layer was significantly water-repellent and highly protective against atmospheric corrosion of copper.