Figure 5: Mechanical properties of (FL)8 hydrogels.
From: Forced protein unfolding leads to highly elastic and tough protein hydrogels
(a) Representative stress-strain curve of (FL)8 hydrogels. The average breaking strain is 450±90% (n=16), Young’s modulus at 15% strain is 16±3 kPa (n=27), and breaking stress is 35±6 kPa (n=16). (b) Stressing–relaxation cycles from the same sample show that hydrogels built from (FL)8 exhibit massive energy dissipation. It is of note that hydrogels show plastic deformation when stretched to higher strains due to the incomplete recovery of the hysteresis during consecutive stretching–relaxation cycles. (c). The hysteresis exhibited by (FL)8 hydrogels can be largely recovered. (d) Kinetics of the hysteresis recovered shows a complex time course. The first ∼60% hysteresis can be recovered within 2 s, while the remaining ∼40% hysteresis is recovered much more slowly following an apparent double exponential kinetics. (e) Consecutive stress-strain curves of (FL)8 hydrogels with different strains in 3 M GuHCl. Curves with different final strains are in different colours. Denatured (FL)8 hydrogels show a much smaller Young’s modulus than native ones and do not exhibit appreciable hysteresis in stretching–relaxation cycles.
