Fig. 4 Characterization of MMCM-B (20 wt% MOF loading). Morphologies of MMCM-B at spinning speed of 2000 rpm: (a, b) cross-sectional images, (c) surface image. Morphologies of MMCM-B at spinning speed of 3000 rpm: (d, e) cross-sectional images, (f) surface image. (Scale bar=500 nm)