A shape-memory temperature-responsive valve for directional liquid transport control

Directional liquid transport (DLT) is essential for water harvesting, thermal management, and biomedical systems. Temperature-responsive structures offer a promising route for adaptive DLT control. However, fully passive and reversible shape transformation with effective directionality remains challenging. Here, we present a temperature-responsive valve (TRV) that converts thermal stimuli into uni-directional liquid transport via automatic mechanical deformation. The proposed unit is a shape memory alloy (SMA) slice embedded within an elastic tube lined with internal fin arrays. Upon heating, the curvature of SMA slice increases. Thus, the fin array beneath is compressed into an asymmetric configuration that generates driving force for stable uni-directional liquid transport. It operates across a wide wettability range of liquid, and supports modular configurations for multifunctional integration. We introduce key applications including reconfigurable direction switching, multimode mixing, and thermal patterning. The system achieves to transport ~ 3000 µL liquid volume over ~ 66 mm, which outperforms the existing DLT systems of thermal stimuli. These performances originate from augmented Laplace pressure difference, reverse pinning, and asymmetric wetting structure. This work establishes a scalable framework of reconfigurable DLT control, offering new opportunities for intelligent microfluidic systems.