Zwitterionic Poly(aryl ether ketone) with Water-Actuated, Reshaping-Reconfiguration Ability and Triple Shape Memory Effect

We synthesized shape memory poly(aryl ether ketone) (PAEK) and grafted carboxylic acid pyridine zwitterions onto the main chains for fabricating the zwitterionic PAEK (ZPAEK) material. ZPAEK exhibited a Tg of around 120 °C, great thermal stability, and mechanical performances, and heat-triggered shape memory behaviors, including high shape recovery ratio (over 98.7%) and fixity ratio (over 98%). Besides, we improved the hydrophilicity of PAEK by incorporating carboxylic acid pyridine zwitterions, for the first time, achieving the exceptional water-actuated shape memory behaviors for PAEK at room temperature. Furthermore, the controllable reconfiguration behaviors were achieved through the interaction between carboxylic acid pyridine zwitterions and water molecules. For the sample of any temporary shape, after absorbing water, its previous original shape was eliminated, and the deformed temporary shape could be redefined as the "original"shape to construct an unprecedented shape memory cycle, never returning to the first original shape. Additionally, the excellent triple shape memory behaviors of sample were obtained after absorbing water. After the programmable shape fixation processes, the sample of temporary shape could recover to the original shape through the two stages: one was at 110 °C, and the other was at 140 °C. We did believe the water-actuated, reconfigurable, and triple shape memory ZPAEK could be an ideal substitute material for smart sensors and actuators.