Selective water transport across uniform sub-nanometer pores in microfabricated membranes

Abstract

We demonstrate selective water transport through uniform sub-nanometer pores using microfabricated zeolite membranes. Despite advances in micro/nanoscale manipulation, creating well-defined sub-nanometer pores for transport studies is challenging. We fabricated the first model platform to characterize and measure water transport limited to ≈5.5 Å pores over >20 mm2 areas. Furthermore, with these membranes, we elucidated the effect of surface chemistry and pore confinement on water permeability. Using a custom-built flow cell, we showed osmotically-driven water transport where a more hydrophobic interface allows for an ≈10x increase in water flux. These insights will help tailor high performance desalination membranes, and can be extended to gas separation, sensing, and energy storage systems.