A radical polymer for highly efficient solar evaporation and gas separation

The unique magnetic, electronic and optical features derived from their unpaired electrons have made radical polymers an attractive material platform for various applications. Here, we report solution-processable radical polymer membranes with multi-level porosities and study the impact of free radicals on important membrane separation processes including solar vapor generation, hydrogen separation and CO2 capture. The radical polymer is a supreme light absorber over the full solar irradiation range with sufficient water transport channels, leading to a highly efficient solar evaporation membrane. In addition, the radical polymer with micropores and adjustable functional groups are broad-spectrum gas separation membranes for both hydrogen separation and CO2 capture. First principle calculations indicate that the conjugated polymeric network bearing radicals is more chemically reactive with CO2, compared with H2, N2 and CH4. This is evidenced by a high CO2 permeability in gas separation membranes made of the conjugated radical polymer.