Enhanced rigidity and rupture strength of composite hydrogel networks of bio-inspired block copolymers

Rombouts, W.H.; Colomb-Delsuc, M.; Werten, M.W.T.; Otto, S.; Wolf, F.A. de; Gucht, J. van der


We study self-assembled composite networks consisting of silk-like protein fibers dispersed in a soft gel matrix formed by collagen-like block copolymers. Rheological analysis shows that the composite networks have significantly higher storage moduli than either of the single networks. This is caused by bundling of the fibrils due to depletion attraction induced by the collagen-like polymers. Moreover, the soft background network significantly modifies the non-linear response of the fibrillar network; the strain-hardening disappears almost completely and the stress and strain at which the gel breaks increase strongly, resulting in tougher hydrogels.