Birmingham researchers create UV-responsive gel that liquefies, reheats and dissolves in acid

Researchers at the University of Birmingham have engineered a novel gel that can be toggled between a solid-like state and a flowing liquid by applying distinct external cues. The material relies on helical foldamer molecules connected through palladium ions, forming a network that traps liquid. Ultraviolet light triggers a shape change in the foldamers, collapsing the network and producing a liquid-like phase; subsequent heating re-assembles the network, restoring the gel.

Exposure to acid severs the palladium-foldamer links, completely breaking down the structure. The scientists also converted the system into a water-based hydrogel, opening possibilities for medical applications such as targeted drug delivery. Detailed atomic-scale analysis was achieved using DNP-enhanced solid-state NMR, cutting years of work to hours. Published in the Journal of the American Chemical Society, the discovery offers a platform for smart sensors, switchable catalysts and responsive biomedical materials.