Studies of the Composition of Copper Sulfide Layers on Polyamide

Abstract

The CuxS layers on polyamide obtained by sorption-diffusion method using highly sulfured polythionic acids (H2SnO6, n = 21 ÷ 33) are studied. These layers are formed when sorbed into polyamide ions of higher polythionates and sulfur react with a solution of copper(I-II) salt. By potentiometric study it is determined that a value x in electrically conductive or semiconductive copper sulfide layers varies in the interval 1 < x < 2. That was confirmed by X-ray diffraction studies of the layers obtained. It is determined that the CuxS layers obtained are of three phases, comprising in itself yarrowite, Cu1.12 – 1.18S, anilite, Cu1.7 – 1.8S, and djurleite, Cu1.91 – 1.95S. The ratio between the concentrations of phases depend on the period of polyamide sulfuration in a solution of polythionic acid and on the period of sulfured polymer treatment with a copper(I-II) salt solution. Djurleite prevails in the composition of CuxS film if PA is sulfured shortly (few min) in a solution of H2SnO6. When the period of sulfuration is prolonged the peaks of djurleite slightly decreases and the peaks of anilite increases, and on further prolongation – the phases of anilite and yarrowite become dominating. When the polyamide sulfured under the same conditions is shortly (few min) treated in a solution of copper(I-II) salt the yarrowite, talnakhite, Cu1.06, and anilite phases are detected, but if treatment in a Cu(I-II) salt solution is prolonged – formation of sulfide phase containing more copper – anilite is observed. Thus, in the course of sulfured polyamide treatment with ta solution of Cu(I-II) salt, the phase composition of CuxS film changes in the direction of increasing values of x.