ABSTRACT This study proposes a membrane based on a thermally driven molecular conformation switch, which can precisely control the flow rate of water droplets. This material achieves programmable control of droplet movement at the solid‐liquid interface through temperature‐induced molecular conformational changes. This material constructs a regional self‐assembly structure on the polydimethylsiloxane substrate, enabling reversible changes in droplet adhesion and sliding speeds at different temperatures. Among them, Trichloro(1H,1H,2H,2H‐tridecafluoro‐n‐octyl)silane exhibits charge transfer rates of 0.06 nC/s at 20°C and 3.97 nC/s at 70°C, with a rate increase of 651% due to the degree of molecular chain bending. On this basis, self‐assembled molecular layers of different regions can be constructed on the same membrane, and the water flow rate can be actively controlled according to the temperature. The chemical stability of the self‐assembled membrane was confirmed by atomic force microscopy and X‐ray photoelectron spectroscopy characterization. Based on this principle, eight series of molecular chain charge transfer rates of different lengths and elements were evaluated simultaneously. A programmable model cooling system was designed, which drives the movement of liquid droplets through electro‐adhesion, significantly improving the local heat exchange efficiency. This research provides new design strategies and theoretical foundations for thermal management and adaptive microfluidic systems.
Liu et al. (Sun,) studied this question.