Formation of a defect‐free polyimide/zeolitic imidazolate framework‐8 composite membrane for gas separation: in‐depth analysis of organic–inorganic compatibility

Abstract BACKGROUND The incompatibility between polymer matrix and filler usually leads to the formation of nonselective voids at the polymer/filler interface, which subsequently lowers the gas separation performance. In view of this, the effectiveness of (3‐aminopropyl)triethoxysilane (APTES) in promoting the interaction between alumina and polyimide (PI), as well as PI and zeolitic imidazolate framework‐8 (ZIF‐8) during the synthesis of PI/ZIF‐8 composite membrane was assessed experimentally. The experimental data also were verified through the calculation of binding energy via molecular simulation. RESULTS It was found that APTES improved the adhesion between alumina‐PI and allowed the formation of a defect‐free alumina‐supported PI membrane up to five layers of PI dip‐coating. Similarly, the compatibility between PI–ZIF‐8 also was shown to be improved by APTES. Indeed, the optimum CO 2 permeance and CO 2 /N 2 selectivity were found at 93.47 GPU and 7.50, respectively, at five layers of ZIF‐8 dip‐coating. In this work, the polymer‐filler compatibility also was verified through molecular simulation whereby a lower binding energy was obtained for system incorporated with APTES. CONCLUSION In short, the results indicated that APTES was effective in stabilizing the PI/ZIF‐8 composite membrane. The polymer‐filler compatibility also was successfully evaluated through the simple molecular simulation approach without requiring time‐consuming experiments. © 2018 Society of Chemical Industry