Step 10). Finally, the protective PMMA layer was dissolved by immersing the sample in acetone (Figure , Step 11). Before removing the sample from the container, the acetone was exchanged for methoxyperfluorobutane (MPFB). Since MPFB has a lower surface tension than acetone, the solvent exchange prevents rupturing of the membrane when removing the sample from the liquid phase and drying it at ambient conditions. Using this transfer process, it was possible to prepare hybrid membranes with freestanding areas of up to ∼ 6 × 10 4 µm 2 . The thickness of the as-prepared freestanding membranes was typically between ∼25 and ∼30 nm, as indicated by AFM height profiles measured at the step edges of intentionally made scratches. Exemplary AFM images of the transferred hybrid films are provided in the Supporting Information, Section S2.