Research / 2019 / Article / Fig 1

Research Article

Flexibility of Metal-Organic Framework Tunable by Crystal Size at the Micrometer to Submillimeter Scale for Efficient Xylene Isomer Separation

Figure 1

Thermodynamics/kinetics of guest-driven flexibility and shape-memory behavior. (a) Guest-driven flexibility. The guest-included open phase is thermodynamically stabilized by the host-guest interaction. There is a negligible energy barrier from the guest-free open phase to the closed phase, so that guest removal directly gives the closed phase. (b) Shape-memory behavior. There is a moderate energy barrier from the guest-free open phase to the closed phase, so that guest removal gives the metastable guest-free open phase, which can transform to the closed phase by heating. (c) Coexisting of guest-driven flexibility and shape-memory behavior (changes of the guest on the reaction direction are omitted for clarity).