СИНТЕЗ КОМПОЗИТІВ ПОЛІПІРОЛ – КАРБОНОВІ НАНОТРУБКИ МЕТОДОМ ЦИКЛІЧНОЇ ВОЛЬТАМПЕРОМЕТРІЇ

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Synthesis of polypyrrole-carbon nanotube composites was carried out by cyclic voltammetry from aqueous solutions at different ratios between components at room temperature. The influence of the composition of the reaction mixture and the speed of the potential sweep on the values of the potentials and currents of the oxidation peaks of polypyrrole was investigated. With an increase in the content of nanotubes in the range of 1−5%, an increase in the oxidation current of polypyrrole is observed at low potential sweep rates from 1.0 to 2.8 mA. This fact indicates a sharp increase in the amount of oxidized monomer and indicates the low resistance of the synthesized composites. A further increase in the CNT content leads to slower growth and even, in some cases, a decrease in currents. The largest amount of electrochemically active product is obtained at low potential sweep speeds and a CNT content of more than 5%. At lower CNT contents, their number is insufficient to ensure participation in the process of deeper coating layers. When the speed of the potential sweep increases for solutions with a CNT content of 0−2%, an increase in PPy oxidation currents is observed, and for higher CNT contents, irregular changes or a decrease in the current are observed. Regarding changes in the potentials of the corresponding peaks, at a potential sweep speed of 10 mV/s, there is a general tendency to decrease the potentials of the peaks with an increase in the content of nanotubes in the initial solution. This fact indicates a decrease in the resistance of the synthesized composites. An increase in the potential sweep speed up to 30 mV/s leads, on the contrary, to an increase in peak potentials. An increase in the potentials of the corresponding peaks indicates the occurrence of an additional potential jump in the layer deposited on the surface of the electrode, which can be explained by an increase in the resistance of the synthesized films as their thickness increases. At even higher potential sweep speeds (50–100 mV/s), the amount of oxidized pyrrole and the thickness of the films deposited on the electrode are small. Accordingly, their supports are close and no significant changes in the potentials of the oxidation peaks are observed.