The stress-strain curves of STz25 and STz30 before and after equilibration in 15 wt.% KOH are shown in Figure S7b, respectively, and the mechanical parameters are summarized in Table . When fully dry, both STz25 and STz30 membranes were brittle and easily prone to damage from bending, with respective tensile strengths of 27.0 and 18.2 MPa.