Fig. 4: Toughening mechanism.
From: Hierarchically aligned heterogeneous core-sheath hydrogels
XRD patterns (a), Iq2-q SAXS profiles (b), variations of crystallinity in drying and swollen states (c), scattering intensity versus azimuthal angle plot (d), and Herman’s factor and corresponding 2D SAXS patterns (e) of HHPC-1.5 hydrogel stretched at different strains from 0 to 30. The colored arrows in (b) represent the qmax positions. Data in (c) and (e) are presented as mean values ± SD (n = 3). Schematic illustrations of coordinatively toughening mechanism, including the sheath-dominant energy dissipation mechanism by melting and reconstruction of crystalline domains (f, g), inner layer-dominant crack-blunting by crack bridge and crack deflection (g), and hierarchical fracture mechanism, that is, successive rupture of crystalline domains, nanofibrils and microfibrils for dissipating energy before macroscopic crack propagation (h).
