Preparation of nanoporous covalent framework membranes with hydrophilic channels and tunable porosity by introducing ionic liquid

Abstract

Nanoporous covalent framework membrane was synthesized by blending of urea network sol, poly(ethylene glycol) and ionic liquid. The cross-linked network sol was synthesized by polymerizing tetrakis(4-aminophenyl)methane (TAPM) and hexamethylene diisocyanate (HDI). The network membrane was generated via the interplay between phase separation and sol-gel transition. We studied the effect of the ratio of poly(ethylene glycol) and ionic liquid on the porosity of the membrane. Chemical structure of the membrane was measured by Fourier transform infrared spectroscopy (FT-IR). The morphology and porous property of the membrane were characterized by scanning electron microscope (SEM) and porosity analyzer. We obtained the membrane with hydrophilic channels and tunable porosity by introducing ionic liquid. We confirmed that the water permeability of the membrane was faster than that of nanoporous covalent framework membrane prepared by using only poly(ethylene glycol). In addition, The porosity of the membrane was controlled by adjusting the composition of urea network sol, poly(ethylene glycol) and ionic liquid.