The effect of the PVA hydrolysis degree on the electrical properties of organic resistive memories based on PVA + CNT composites

Abstract

This work studies the interaction effect between functionalized multiwall carbon nanotubes (f-CNTs) and a polymeric matrix in the electrical behavior of resistive memories. f-CNTs were synthesized by spray pyrolysis using xylene-ethanol (1:0.8 v/v) as the reaction mixture, allowing the in-situ functionalization (OH, COOH, CH, C–OH groups) on the f-CNT surface and, then, improving their solubility in polar solvents as well as their dispersion in a polymeric matrix. Two types of polyvinyl alcohol (PVA) with different hydrolysis degrees were used, PVA with high hydrolysis (HD) degree (Mw 89,000-98,000, 99 + % hydrolyzed) and PVA with low hydrolysis (LD) degree (Mw 9000-10,000, 80% hydrolyzed), for the fabrication of the organic resistive memories. The PVA + f-CNT composites show significant differences in the morphology, thickness and current-voltage (I-V) electrical behavior as a function of the hydrolysis degree of the PVA matrix. In the case of IV measurements, our results are broadly different from those reported in the literature, PVA-LD + f-CNT composites at 1, 3 and 5 wt% f-CNTs show rewritable behavior, whereas PVA-HD + f-CNT composites the rewritable behavior started at 5 wt%. From here, we conclude that the polymeric matrix can play an essential role in the resistive memory behavior.