Shape memory polyimides based on different pendant structures

Shape memory materials with controllable property for harsh condition like high temperature are strongly required. Here, three novel shape memory polyimides (SMPIs) have been realized by bearing various side-chain groups (-H, -CH3 or -OCH3) to study their relationship between structures and shape memory performances. These PIs possess excellent shape memory behaviors in both fixity ratio (Rf > 99.1%) and recovery ratio (Rr > 86.8%). The rheological information revealed different creep and stress relaxation accompanied with the different SMPIs. Meanwhile, fractional free volume (FFV) and simulating of geometry optimized molecule chain via Materials Studio were referred to reveal the inner relationship between shape memory performance and polymer structure. This work provides a design metric to guiding significance to the structure design of shape memory polyimides.