On Demand Bidirectional Shape Transformations and Novel Chiral Actuators of Photomediated Shape Memory Polymer Film Based on Photothermal OEGy-W 18 O 49 Nanowires

The spatially controllable shape-shifting behaviors of a planar two-dimensional (2D) film to three-dimensional (3D) shapes upon external stimuli are of paramount significance for the development of smart materials. Herein, the present work focuses on fabricating plain film whose shape can be remotely and spatially transformed into various 3D configurations via the formation of a laser-induced temperature gradient; when subjected to laser irradiation, the prestretched hybrid films exhibit out-of-plane bending behavior owing to anisotropic chain relaxation and strain energy release. On this basis, various sophisticated shape transformations can be achieved by site-specific irradiations of laser with a controllable magnitude. Meanwhile, shape morphing involving reversible bending transformations can also be realized by employing the laser on the corresponding opposite side of the hybrid films. Remarkably, under a 160 mW/cm 2 simulated sunlight illumination, the transformation of flat 2D film into 3D chiral actuators is driven by material anisotropy and geometrical heterogeneity of a bilayer strip design, and it yields right and left-handed helix, the morphologies of the helix shape can be precisely tailored by the strip angles and strain values.