Closely packed polymer films of monolayers adsorbed on the copper surface were prepared by chemical modification of a 11-mercapto-1-undecanol HO(CH2)(11)SH (MUO) self-assembled monolayer with alkyltrichlorosilanes C(11)H2(+1)SiCl(3) (C2TCS) and water. The maximum protection efficiency, 94.7% for the MUO monolayer modified with C18TCS in a dilute solution against copper corrosion in aerated 0.5M Na2SO4 was obtained by polarization and impedance measurements. A Fourier transform infrared reflection absorption spectrum of the surface covered with the monolayer showed the absence of hydroxyl groups in the layer, implying the formation of a regularly arranged polymer monolayer film on the surface. The protection efficiency of the C8TCS-modified MUO monolayer against copper corrosion in aerated 0.5M Na2SO4 was unchanged in the range of the immersion time up to 10 h, indicating a fairly high persistence of the layer in the protection of copper against corrosion in the neutral solution. This layer was less protective against corrosion in an aerated Na2SO4 solution at pH 3, X-ray photoelectron and Auger electron spectra of copper for the C8TCS-modified MUO monolayer. adsorbed on the copper surface after exposure of the surface to air for 231 h revealed the presence of metallic copper on the surface, suggesting a high protection ability of the layer against atmospheric corrosion of copper fine devices. This result was also supported by the contact angle of the monolayer-coated copper surface after exposure to air for 30 days.