High performance soft fiber-reinforced sodium alginate/polyacrylamide double-network hydrogels

Strong and stretchable hydrogels are in great demand but challenging due to the trade-off between the strength and stretchability. Here, we successfully prepared highly strong and stretchable sodium alginate/polyacrylamide（SA/PAM） double network（DN） hydrogels by using swollen calcium alginate fiber（CAF） as the first energy dissipating network. The swollen fibers contributed two functions: the homogeneous SA ionic crosslinkedpolymer networks and the soft fiber reinforcement. In contrast to the stiff fiber, the soft CAF provide more effective energy dissipation transferring from soft fiber to the liquid hydrogel. The as-prepared hydrogels demonstrated a high tensile strength（0.83 MPa）, high stretchability（4230 %）, and high toughness（15.7 MJ/m3）,as 5, 3 and 14 times of the SA/PAM hydrogels. This soft fiber-reinforced strategy offers a new way for preparing high-performance hydrogels, broadening their applications areas.