Dodecathionic Acid as Precursor for Formation of Semiconducting and Conducting Layers on the Surface of Polyamide 6

Abstract

By a study of IR and UV absorption spectra it is shown that the dodecathionate anions, S12O6
2–, are sorbed-diffused into
a polyamide 6 films if they are treated with the 4·10–3 mol⋅dm–3 water solution of dodecathionic acid, H2S12O6, at the
temperatures of 10 °C − 40 °C. The values of sulfur concentration obtained in polyamide 6 (up to ∼11 mmol⋅cm–3) are
significantly higher than those, obtained in the studies in which the sorption of pentathionate ions from the K2S5O6
solution or from 2·10–3 mol⋅dm–3 water solution of dodecathionic acid, H2S12O6, by PA films has been studied. The
concentration of sorbed dodecathionate ions increases with the increase of time of treatment, concentration and
temperature of a H2S12O6 solution. The copper sulfide, CuxS, layers are formed in the surface of polyamide 6 film if the
sulfurized polymer is treated with a solution of Cu(II/I) salt at 80 °C temperature: the anionic particles S12O6
2– containing
sulfur atoms of low oxidation state react with the copper ions. The conditions of a polymer initial sulfurization determine
the concentration of copper and the composition of sulfide layer: the concentration of copper in the polyamide 6 film
increases with the increase of time and temperature of initial sulfurization, and varies from ∼0.5 mmol·cm–3 to
∼3.0 mmol·cm–3; the stoichiometrical composition of CuxS layers on polyamide 6 formed according the data of chemical
analysis varies from Cu~0.3S to Cu~1.0S. The regularities determined enable formation by sorption-diffusion method of
electrically conductive (∼60 Ω/ – ∼1.0 Ω/) copper sulfide layers using the solution of dodecathionic acid as a
polyamide 6 sulfurization agent.