TY - JOUR

T1 - Nanocomposite Hydrogels - Fracture Toughness and Energy Dissipation Mechanisms

AU - Klein, Andrea

AU - Whitten, Philip, G.

AU - Resch, Katharina

AU - Pinter, Gerald

PY - 2015/10/8

Y1 - 2015/10/8

N2 - In this study, fracture toughness of nanocompositehydrogels is quantified, and active mechanisms for dissipationof energy of nanocomposite hydrogels are ascertained.Poly(N,N-dimethylacrylamide) nanocomposite hydrogels areprepared by in situ free radical polymerization with the incorporationof Laponite, a hectorite synthetic clay. Transmissionelectron microscopy proves exfoliation of clay platelets thatserve as multifunctional crosslinkers in the created physicalnetwork. Extraordinary high fracture energies of up to 6800J m22 are determined by the pure shear test approach, whichshows that these soft and stretchable hydrogels are insensitiveto notches. In contrast to single- and double-network hydrogels,dynamic mechanic analysis and stress relaxation experimentsclarify that significant viscoelastic dissipation occursduring deformation of nanocomposite hydrogels. Similar todouble-network hydrogels, crack tip blunting and plastic deformationalso contribute to the observed massive fracture energies.

AB - In this study, fracture toughness of nanocompositehydrogels is quantified, and active mechanisms for dissipationof energy of nanocomposite hydrogels are ascertained.Poly(N,N-dimethylacrylamide) nanocomposite hydrogels areprepared by in situ free radical polymerization with the incorporationof Laponite, a hectorite synthetic clay. Transmissionelectron microscopy proves exfoliation of clay platelets thatserve as multifunctional crosslinkers in the created physicalnetwork. Extraordinary high fracture energies of up to 6800J m22 are determined by the pure shear test approach, whichshows that these soft and stretchable hydrogels are insensitiveto notches. In contrast to single- and double-network hydrogels,dynamic mechanic analysis and stress relaxation experimentsclarify that significant viscoelastic dissipation occursduring deformation of nanocomposite hydrogels. Similar todouble-network hydrogels, crack tip blunting and plastic deformationalso contribute to the observed massive fracture energies.

M3 - Article

SP - 1763

EP - 1773

JO - Journal of polymer science : B, Polymer physics

JF - Journal of polymer science : B, Polymer physics

SN - 0887-6266

IS - 53

ER -