S1 The liquid phase epitaxy approach for the successful construction of ultra- thin and defect-free ZIF-8 Membranes: Pure and mixed gas transport study. Osama Shekhah, 1 Raja Swaidan, 2 Youssef Belmabkhout, 1 Marike du Plessis, 3 Tia Jacobs, 3 Leonard J. Barbour, 3 Ingo Pinnau, 2 Mohammed Eddaoudi 1 * Table of content: 1. Experimental: - Synthesis of ZIF-8 crystals S3 - ZIF-8 membrane fabrication S3 - Characterization of ZIF-8 crystals and ZIF-8 membranes S3 - Pure gas permeation measurements S4 - Mixed gas permeation measurements S4 - Adsorption and kinetics S4 - Measurement of gas adsorption equilibrium and kinetics using Rubotherm Magnetic balance S4 - Figure S1. Structure of ZIF-8 with the growth along the (100) direction, the 2- methylimidazol (mIm) organic ligand bridge, cavity and window size are also shown. S6 - Figure S2. Schematic representation of the permeation setup used for the pure- and mixed-gas permeation measurements. S7 - Figure S3. PXRD diffractograms of ZIF-8 thin film membranes grown on alumina substrate using the LPE method, (a) after 150 growth cycles (b) after 300 growth cycles. All diffractograms were background-subtracted. S8 - Figure S4: Cross-section SEM image of the ZIF-8 thin film fabricated (150 cycles) using the LPE method with a thickness of ~0.5μm. S9 - Figure S5. Permeability of single gases measured for the ZIF-8 membrane fabricated using the LPE method at (T = 308 K and P= 18 psig) versus the Lennard-Jones diameter of the gases. S10 - Figure S6. Permeate pressure of CO 2 , measured versus time using the constant volume/variable pressure technique on ZIF-8 membrane fabricated using the LPE method at 308 K and 18 psig, where  is the calculated time-lag. S11 -Figure S7. Sorption coefficient of single gases measured for the ZIF-8 membrane at (T = 308 K) versus the boiling point of the gases. S12 Electronic Supplementary Material (ESI) for Chemical Communications This journal is © The Royal Society of Chemistry 2014