fig7

Figure 7. Stress-strain curves and mechanical properties of FT PVA (A-C), FS PVA (D-F), and DFS PVA (G-I, with stretching ratio of 1) hydrogels with different mass fractions of PVA. FT: Frozen-thawed; PVA: polyvinyl alcohol; FS: frozen-salted out; DFS: directional freezing and salting-out.