Sequence-controlled block copolymerization strategies for achieving high intrinsic thermal conductivity of polyimide with exceptional shape memory capability

Achieving high thermal conductivity of shape memory polyimides without compromising their shape memory performance and mechanical properties is challenging. To solve this issue, a molecular structure design strategy was employed to synthesize a range of sequence-controlled block copolyimides through the introduction of soft segments into rigid segments, thereby regulating molecular chain mobility. An intrinsically thermally conductive shape memory block copolyimides with rapid shape recovery speed, exceptional shape memory and mechanical properties were achieved. Through regulating the proportion of soft segments, strong physical cross-linking structures, including π-π stacking interactions and molecular chain entanglements, were generated, ultimately achieving shape fixity and recovery ratios of 97.4 % and 99.6 %, respectively. Owing to their relatively ordered molecular structures, which contributed to high intrinsic thermal conductivity, the developed copolyimides displayed a rapid shape recovery speed of 3.5 s at a trigger temperature of 275 °C. The molecular structure design strategies employed might offer deep insight into the exploration of shape memory polyimides.