3D-Printed Biomimetic Shape-Memory Rectifier for Smart Directional Transport of Diverse Low-Surface-Tension Liquids and “Chip” Transfer

The directional transport of low-surface-tension liquids (LSTLs) is crucial in applications such as oil/water separation, electrochemical sensing, and microreactors. However, the development of surfaces capable of the reversible directional manipulation of diverse LSTLs remains challenging. Herein, an LSTL is presented rectifier based on dual-responsive shape-morphing re-entrant microplate arrays (SMRMAs) fabricated via 3D-printed templating. Owing to photothermal and shape-memory effects, the global topography (e.g., bending angle) of the SMRMAs can be reversibly fine-tuned in response to alternating near-infrared rays/mechanical stimuli, thereby realizing the directional steering of diverse LSTLs (e.g., ethanol, n-hexane, ethylene glycol, hexadecane). Fundamental physics combined with simulation analysis provides insights into the underlying mechanism of the directional delivery of LSTLs. The influence of rectifier morphology on the directional spreading behavior of the LSTLs is also studied. An optimized rectifier integrated with the all-in-one SMRMAs can achieve the on-demand dispensation of LSTLs as well as laboratory-on-chip and “chip” mass transfer. Notably, given its shape-morphing capability, the SMRMAs can function as a smart mechanical hand, selectively capturing and releasing objects as needed, thus providing an innovative platform for versatile bifunctional applications. This new technology will be useful in the development of smart microfluidic devices and cross-species manipulators.