2D material-enhanced multi-fold self-sensing and programmable deployable lattice structure.

The development of intelligent and programmable smart composite structure that can remember and restore their original shape after being extensively deformed is highly sought after for a wide variety of applications, such as deployable and morphing structures, soft robots, and smart infrastructure. Despite recent advancements, there remains a plethora of unexplored possibilities in the field of deployable structures utilizing shape programmable and intelligent composite materials. The aim of this research is to manufacture a deployable structure that is intelligent enough to monitor the deployment and programmable to be deployed in specific way. Here, a smart deployable auxetic structure is reported that not only possesses thermal and piezoresistive sensing properties but also acts as a thermally activated intelligent shape memory polymer composite (iSMPC). We have fabricated an intelligent fabric and embedded it as reinforcement within a polyurethane-based shape memory polymer matrix to make an intelligent auxetic (A-iSMPC) structure. It has been demonstrated that the intelligent fabric enhances the overall mechanical properties of the auxetic structure and allows monitoring the temperature variation and strain changes during shape programming and recovery. The A-iSMPC offered a negative Poisson's ratio of - 0.44, shape recovery ratio of 96%, shape fixity ratio of 88% and compaction ratio of 62%. With its shape memory, auxetic, thermal and piezoresistive sensing capabilities, this iSMPC has the potential to be a multifunctional and multipurpose structure for a variety of applications.