Tailored cocrystal architectures enable highly reversible actuation in crystalline polymer networks

Low levels of reversible actuation behavior have consistently been observed in mechanically programmed crystalline polymer networks (CPNs), which poses potential limitations for soft actuators' applications despite the ease of synthesizing CPNs. Here, we demonstrate a universal solution that overcomes this limitation by optimizing the lattice match between the CPN and the skeleton crystals. In particular, constructing unique cocrystal structures in the actuation domains is an effective optimization tool, as it can fine-tune the lattice features of the CPN by altering the cocrystal composition. As a result, the perfect lattice match is achieved through tailored cocrystals, resulting in a highly ordered arrangement of the actuation segments along the orientation of skeleton segments during activation. This maximizes the CIE effect and enables the target CPNs to clearly exhibit superior actuation capabilities compared to previous reports. This optimization effectively counters the decline in actuation capability caused by the integration of the photothermal conversion factor. Consequently, our materials can achieve remarkable shape switching between infrared irradiation and at room temperature, which makes them a promising option for use in artificial muscles and information security.