Modification of polyamide surface with CuxS layers

Abstract

Various polymers, modified by copper sulphides, represent a new class of materials – composites with novel properties. Copper sulphide is an interesting material for its metal–like electrical conductivity, chemical–sensing capability and ideal characteristics for solar energy absorption. Consequently, copper sulphides modified polymers are used: i) as the conductive substrates for deposition of metal and semiconductors; ii) as gas sensors functioning at temperatures tending to room temperature; iii) as polarizer of infrared radiation; and iv) as active absorbents of radio waves. Electrically conductive CuxS layers can be prepared by the sorption-diffusion method, described earlier [1–3]. By this method, the surface of a polymer is initially treated by the solution containing sulfurization agent, and then by the aqueous solution of metal salt. Sodium polysulphides, polythionic acids and polythionates, thiourea, and sulphur in carbon disulphide solution have already been used for sulfurization of polymer foils by different methods. The sulfurization process using these agents is prolonged, many of them are quite harmful, and sometimes their preparation is complicated. We have chosen polyamide as a cheap, chemically stable and flexible substrate. Polyamide (PA) as semi-hydrophilic polymer is capable to absorb ions or molecules of various electrolytes from aqueous and no aqueous solutions. In this work we report the preparation of electrically conductive CuxS layers on polyamide by the sorption-diffusion method with the use of molten sulphur as the sulfurization agent. The phase composition of the CuxS layers, their electrical conductance were studied by the methods of X–ray diffraction (XRD) and by the measurements of electrical sheet resistance. [...]