Synthesis, characterization and memory properties of novel organosoluble polyimides

Two novel series of aromatic polyimides were prepared from 2,2-bis(4-amino-3-trifluoromethylthylphenoxy) biphenyl, 2,2-bis(4-amino-3-methoxyphenoxy)biphenyl with 3,3,4,4-benzophenonetetracarboxylic dianhydride (BTDA), 3,3,4,4-diphenylsulfonetetracarboxylic dianhydride (DSDA) via a one-step procedure. The resulting polymers were fully characterized, and they exhibited excellent organosolubility. These polyimides are thermally stable with 5% weight loss over 430 degrees C, and glass transition temperatures of the polyimides were found to be 225-262 degrees C. Resistive switching devices with the configuration of Al/polymer/indium-tin oxide were constructed from these polyimides by using conventional solution coating process. Devices with all polyimides exhibited nonvolatile and rewritable flash type memory characteristics with turn-on voltage at -1.1 to -2.8V. The ON/OFF current ratio of these devices was larger than 10(4), and the retention times can be as long as 10(4)s. The theoretical simulation based on the density functional theory suggested that greater distinct charge separation between the ground and charge transfer states led to a highly stable memory behavior. Copyright (c) 2016 John Wiley & Sons, Ltd.