▎ 摘　　要

We use first-principles calculations to explore the change of the separation properties of strained porous graphene membranes. Small to moderate lateral strain, biaxial (1% - 2%) or uniaxial (1% to 7%, depending on the direction), always increases the percolation barriers of the same passing molecules (e.g. methane, cyclopropane, neopentane) regardless of the pore size, shape and functionalization, when compared with their strain-free values. The pore size expansion under such strain is no match for the electronic structure redistribution, which leads to more rigid pore plane (against the out-of-pore-plane bending). Larger strain will eventually make the geometric enlargement dominant over the electronic effect and the barrier falls. The energy barrier in response to biaxial strain can rise by 0.2 - 0.3 eV, corresponding to a substantial drop of gas transport rate by three to five orders of magnitude. The barrier-to-strain response is highly anisotropic for uniaxial strain. Strain (6% - 7%) in the direction of the longest pore diameter can cause the barrier to rise even more by 0.3 - 0.4 eV (gas percolation rate slashes by five to seven orders of magnitude), which can effectively shut down the molecules' percolation. Our results demonstrate that there is plenty space for strain engineering the separation performance of porous graphene membranes.