▎ 摘　　要

NOVELTY - Membrane (I) comprises: a first layer comprising a porous graphene-based material; a second layer comprising a porous graphene-based material; a channel positioned between the first layer and the second layer, where the channel has a tunable channel diameter; and at least one spacer substance positioned in the channel, where the spacer substance is responsive to an environmental stimulus. USE - The membrane is useful for water filtration, water desalination, water purification, immune-isolation, timed drug releasing, hemodialysis or hemofiltration (claimed). ADVANTAGE - The membrane: utilizes the spacer substance, which is responsive to an environmental stimulus including variations in temperature, pressure, pH, ionic concentration, solute concentration, tonicity, light, voltage, electric fields, magnetic fields and/or pi -bonding availability (claimed), hence the membrane is tunable selectivity. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) altering (M1) membrane permeability, comprising exposing the membrane (I) to the environmental stimulus to alter membrane permeability, where the membrane comprises the first layer, the second layer and the channel between the first layer and the second layer, and the channel has a diameter that is altered upon exposing the membrane to the environmental stimulus; (2) water filtration, water desalination, water purification, immune-isolation, timed drug releasing, hemodialysis or hemofiltration (M2), comprising exposing the membrane (I) to the environmental stimulus; (3) making (M3) the membrane (I); and (4) membrane (II) comprising the first layer, second layer, the channel positioned between the first layer and the second layer, and a means for increasing and/or decreasing the diameter of the channel in response to the environmental stimulus.