Accelerating effect of NaNO2 on the polymer plating of 6-substituted-1,3,5-triazine-2,4-dithiol mono sodium salts

Organic polymer plating properties of 6-substituted-1,3,5-triazine-2,4-dithiol mono sodium salts were investigated in the presence of various supporting electrolytes. Among these, the NaNO2 supporting electrolyte greatly accelerated the film formation rate in polymer plating. The accelerating effect of NaNO2 was further confirmed by comparing plating potentials in the presence of NaNO2 and Na2CO3. The potentiostatic polymer plating of DAN in the presence of the NaNO2 supporting electrolyte took place in the potential range of 1.65-1.8 V (compared against saturated calomel electrode reference). Film formation was influenced by such factors as the pH of solution and both the chemical structure and the concentration of triazine dithiol. In polymer platings, NO2- anions are thought to be electrochemically oxidized to yield NO2. radicals and these radicals react with DAN to yield new thiyl radicals. The thiyl radicals in the DAN molecules couple with each other by means of disulfide bonds, resulting in the growth of polymer film. Organic polymer plating films are shown to contain disulfide bonds, monosulfide bonds obtained by the reaction between allyl groups and thiyl radicals, and network chains. (C) 2001 John Wiley & Sons, Inc.