Date Time Ion-Selective Smart Porous Membranes A research group has developed an ion-selective smart porous membrane that can respond to outer stimuli, potentially paving the way for new applications in molecular separation and sensing applications. Porous thin films have attracted the attention of scientists because of their potential use in sensors, energy harvesting, and ion/molecular separation. Nanostructure properties, such as pore size, thickness, and film density, affect molecular selectivity and molecular permeability. Surface properties also have a significant impact on molecular selectivity. Thus it is important to be able to control both the 3D nanostructures and surface properties of ultrathin porous films.