Fluidic Actuation in a 2D Metal–Organic Framework

We report a solid-state fluidic actuation mechanism in a two-dimensional (2D) metal–organic framework (MOF), PPF-27, driven solely by the thermally induced migration of disordered solvent molecules. Using single-crystal X-ray diffraction (SCXRD) and molecular simulations, we directly observe a redistribution of N,N′-dimethylformamide (DMF) across intra- and interlayer voids, without any change in occupancy or deformation of the host framework. This decoupled behavior yields an unprecedented uniaxial thermal expansion of +541 MK-1, among the highest reported for 2D solids, achieved entirely through solvent motion. By isolating guest mobility from structural flexibility, this work redefines disordered solvents as active, programmable actuators and establishes a new design principle for dynamic porous materials.