Finally, several (nano)fiber composites were reported, where the hydrogel matrix was directly supplemented with gelatin fiber mats, , aramid fibers, glass fibers, or silver nanowires (Figure ). In a work by Kotov and co-workers, a dispersion of aramid nanofibers was combined with a solution of PVA to fabricate tough hydrogels via solvent exchange from DMSO to water. Two samples were selected with a PVA content of 8 wt% and 30 wt%. The respective drop in wa-ter content (92% to 70%) increased the fracture energy and the elastic modulus, accordingly (Γ = 2.3 to 9.2 kJ/m 2 and E = 1.9 to 9.1 MPa). Instead of using nanofibers, He et al. fixated an entire polyaramid fiber mat inside a mold before injecting a pre-gel solution of AAc and PVA. Light-controlled polymerization of the mold followed by freeze-thaw cycles yielded the hydrogel, which was then immersed in a saline solution until the equilibrium swelling state was reached. By immersing the sample in seawater instead of LiCl, the hydrogel specimen reached a fracture toughness of Γ = 195.8 kJ/m 2 , the elastic modulus was not reported. Since the final synthetic step involved the immersion in salt solution, water contents varied and were stated to be in between 40-70%.