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The Molecular Origin of Enhanced Toughness in Double-Network Hydrogels



Taiki Tominaga, Vijay Tirumala, Eric K. Lin, Jian P. Gong, Hidemitsu Furukawa, Yoshihito Osada, Wen-Li Wu


The long-standing pursuit of a synthetic equivalent to tissue cartilage has seen significant new activity with the development of a new materials strategy: double-network hydrogels (DN-gels) prepared from a combination of an anionic polyelectrolyte and a neutral polymer. These hydrogels exhibit an intriguing combination of properties intrinsic to natural cartilage, a low surface friction coefficient and a fracture toughness much higher than either of the constituent materials. The reinforcement of a hard, brittle polymer matrix with a soft, viscoelastic polymer is counter-intuitive and a clear identification of the toughening mechanism remains elusive. In this work, we use neutron scattering measurements to show that the remarkable toughness of DN-gels is due to a deformation-induced mesoscale structure resulting from molecular association between the two polymers. We also show that simple viscosity measurements on the linear chain equivalents highlight the molecular mechanism for the mesoscale structure formation and can be used to provide useful information for the optimal design of artificial cartilage and other soft tissues.
Nature Materials


double-networks, hydrogels, neutron scattering, polymer blends, viscosity


Tominaga, T. , Tirumala, V. , Lin, E. , Gong, J. , Furukawa, H. , Osada, Y. and Wu, W. (2007), The Molecular Origin of Enhanced Toughness in Double-Network Hydrogels, Nature Materials, [online], (Accessed June 14, 2024)


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Created October 21, 2007, Updated October 12, 2021