Degradation of the Memristive Properties of PANI-polystyrene/PVDF-TrFE Interface During Resistance Switching Cycles
Purpose of research. Investigation of the origin of degradation of the memristive properties of polymer nanocomposites PANI-polystyrene/PVDF-TrFE during resistive switching cycles. Methods. Commercial poly (vinylidene fluoride trifluoroethylene) (Solvene 300, Sigma-Aldrich) and emerald polyaniline salt (Sigma-Aldrich, electrical conductivity 2-4 cm/m) with the addition of polystyrene were used as starting polymers to produce a two-layer nanocomposite. The two-layer structure was obtained by consecutive deposition of layers from solutions on aluminium foil with subsequent evaporation of the solvent at -10 °C to reduce the fraction of the PVDF-TrFE crystal phase. Contact electrodes were formed by depositing silver paste with subsequent drying. The structure of the interface before and after 4 resistance switching cycles was analyzed by scanning electron microscopy (FEI Quanta 650 FEG, TESCAN VEGA LM 3), energy dispersive X-ray microanalysis (Bruker X-Flash 6X10) and X-ray phase analysis (Bruker D8 ADVANCE ECO). Results. It was found that degradation of hysteresis of volt-ampere characteristics of these structures is caused by structural changes associated with phase transitions of nanoscale inclusions in the amorphous PVDF-TrFE matrix from segmental β-phase to para-electric α-phase, accompanied by growth at the PVDF-TrFE rod phase interface, 5-15 µm long, with a paraelectric crystalline structure as well as mutual layer diffusion. These processes, in turn, are related to the generation of joule heat at the interfacial interface when negative polarity bias voltages are applied to it. Conclusions. The influence of resistive switching cycles on the degradation of membrane properties detected earlier in polymer interfaces PANI-polystyrene/PVDF-TrFE has been studied. It was established that its caused by changes in the structure of the interphase interface related to phase transitions and inter-layer diffusion.