(380r) A Systematic-Design on a Mechanically-Stable Polymeric Molecular Sieve Membrane for Gas Separation Applications.

There are many strategies proposed to overcome the trade-off limitation that polymer membranes has in terms of separation of gas mixtures. One strategy is to incorporate porous materials with permanent porosity to polymer matrix. However, due to the difference in material characteristics, compatibility between the organic polymer matrix and inorganic porous filler has been a critical obstacle that affects the gas separation performance of the membrane. A way to minimize the incompatibility between two components is to have a porous organic polymer as a filler. The mixed matrix membrane fabricated based on this strategy showed better compatibility at the interface of the matrix and the filler, however, no published result showed membranes with filler loading higher than 40 wt%. Therefore, a new strategy needs to be come up with to fabricate a membrane that has permanent porosity that can act as either a sieve or a highway as itself. Herein, we introduce an innovative approach for crafting a polymeric molecular sieve membrane while upholding the mechanical stability. First, a polymer precursor membrane was prepared as a template varying in number of bulky functional groups. Then, the membrane was fine-tuned by hyper cross-linking the polymer chains with different cross-linker thereby modifying chain distance. Polymer molecular sieve membrane fabricated under various design parameters showed different characteristics in porosity, pore size, separation performance and mechanical stability. Several polymer molecular sieve membranes have been studied through single gas permeance tests to visualize permanent pores in the membrane and to find the right gas separation application. Additionally, mixed gas pemeance tests were also conducted to verify the expected characteristic of the membrane in this study as a sieving material. This study enlightens the opportunity of a polymer molecular sieve membrane as a counterpart to other traditional molecular sieve membranes, and showed the possibility of the class of this membrane material to gas separation and other separation applications.