Li Jianyu, Illeperuma Widusha R K, Suo Zhigang, Vlassak Joost J
School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States.
ACS Macro Lett. 2014 Jun 17;3(6):520-523. doi: 10.1021/mz5002355. Epub 2014 May 19.
The development of hydrogels for cartilage replacement and soft robotics has highlighted a challenge: load-bearing hydrogels need to be both stiff and tough. Several approaches have been reported to improve the toughness of hydrogels, but simultaneously achieving high stiffness and toughness remains difficult. Here we report that alginate-polyacrylamide hydrogels can simultaneously achieve high stiffness and toughness. We combine short- and long-chain alginates to reduce the viscosity of pregel solutions and synthesize homogeneous hydrogels of high ionic cross-link density. The resulting hydrogels can have elastic moduli of ∼1 MPa and fracture energies of ∼4 kJ m. Furthermore, this approach breaks the inverse relation between stiffness and toughness: while maintaining constant elastic moduli, these hydrogels can achieve fracture energies up to ∼16 kJ m. These stiff and tough hydrogels hold promise for further development as load-bearing materials.
承重水凝胶需要兼具硬度和韧性。据报道，有几种方法可提高水凝胶的韧性，但同时实现高硬度和高韧性仍然很困难。在此，我们报道藻酸盐-聚丙烯酰胺水凝胶可以同时实现高硬度和高韧性。我们将短链和长链藻酸盐结合起来以降低预凝胶溶液的粘度，并合成具有高离子交联密度的均匀水凝胶。所得水凝胶的弹性模量可达1 MPa，断裂能可达4 kJ/m²。此外，这种方法打破了硬度和韧性之间的反比关系：在保持恒定弹性模量的同时，这些水凝胶的断裂能可达~16 kJ/m²。这些坚硬且坚韧的水凝胶有望作为承重材料得到进一步发展。
