| 초록 |
Hydrogels are used as scaffolds for tissue engineering, vehicles for drug delivery, actuators for optics and fluidics, and model extracellular matrices for biological studies. The scope of hydrogel applications, however, is often severely limited by their mechanical behaviour. Most hydrogels do not exhibit high stretchability. We have reported the synthesis of a new hydrogel from polymers that form ionically and covalently crosslinked networks. Although such gels contain 90% water, they can be stretched beyond 20 times their initial length, and have fracture energies of 9,000 Jm-2. Even for samples containing notches, a stretch of 17 is demonstrated. We attribute the gels’ toughness to the synergy of two mechanisms: crack bridging by the network of covalent crosslinks, and hysteresis by unzipping the network of ionic crosslinks. These gels serve as model systems to explore mechanisms of deformation and energy dissipation, and expand the scope of hydrogel applications. |
