Characterization of CuxS Layers Obtained by Adsorption-Diffusion Method on Polycaproamide from K2S5O6 Solutions

Cu x S layers on polycaproamide, obtained by the adsorption-diffusion method, have been studied. These layers are formed when the ions of pentathionate (K 2 S 5 O 6 ) sorbed into polycaproamide react with a solution ofcopper(I) salt. By X-ray diffraction studies it was determined that the Cu x S layers obtained are of three phases, comprising covellite (CuS), geerite (Cu 1.6 S), anilite (Cu 1.75 S) and chalcocite (Cu 2 S). The concentration ratio of the phases depends on the period of polycaproamide sulfuration in a potassium pentathionate solution. Chalcocite prevails in the composition of Cu x S film on PKA. The films were characterized by means of IR spectroscopy. IR absorption spectra were investigated in the region of the wavenumbers 200-1400 cm -1 . The characteristic absorption maxima were found in the regions 242-243, 268-290, 339-384, 422-463, 538, 611-612, 879-929, 1018-1095, 1186-1224 cm -1 and assigned, respectively, to δ(S-S-S) and v(Cu-S), γ r (SO 3 ), v(S-S) and v(Cu-S), δ as (O-S-O), δ s (O-S-O), v(Cu-S), ν s (S-O) and ν as (S-O). Measurements of electrode potentials in CuSO 4 solutions of different concentration have shown that the response time and stability of electrodes in Cu 2+ ion solutions depend on the phase composition. Electrodes composed from Cu 1.75 S and Cu 1.6 S are not stable in CuSO 4 solutions. The response time of Cu 2 S electrode depends on concentration change. The change of the potential with an active Cu 2+ ion concentration is linear in the range of 1·10 -3 -4·10 -2 mol·dm -3 , the slope of the linear portion being 31.5 mV per decade. The obtained experimental values have been compared with the theoretical values calculated on the basis of thermodynamic data.