Inherently Porous Atomically Thin Membranes for Gas Separation
Abstract
Membranes made from atomically thin materials promise hundreds of times higher production rates than conventional polymer membranes for separation applications. Graphene is impermeable to gases but becomes selectively permeable once pores are introduced into it but creating trillions of nanopores over large areas is difficult. By instead choosing an inherently porous two-dimensional material with naturally identical pores repeated at high density, we may circumvent this challenge. In this work, we explore the potential of two candidate materials, 2D polyphenylene and graphdiyne. We synthesize cyclohexane-m-phenylene, a monomer of 2D polyphenylene. We then develop an atomic force microscopy technique for measuring the permeance of nanoscopic areas of materials and perform the first gas permeance measurements of graphdiyne and demonstrate molecular sieving. Efforts to scale-up employ continuum transport equations for simple modeling so we develop analytical approximations for the rate of mass transfer rate by advection-diffusion in creeping flow through an orifice plate.