LAUSR

Abstract A facile, efficient and universal strategy to design and fabricate ultra-high-strength biopolymer-based hydrogels was proposed. By the synergistic effect of palygorskite (Pal) nanorods, sodium alginate/polyacrylamide (SA/PAAm) interpenetrating network and metal ion cross-linking, a strong, tough and stretchable SA/PAAm/Pal composite hydrogel was prepared. The results indicate the tensile stress of SA/PAAm hydrogel was enhanced from 65.62 ± 1.40 to 106.12 ± 6.04 kPa after incorporating 5 wt% Pal nanorod into the SA/PAAm hydrogel. The post-treatment of SA/PAAm/Pal composite hydrogels with ionic crosslinking results in a significant enhancement of mechanical performance. The Fe3+-crosslinked hydrogel (SA/PAAm/Pal-Fe) shows the maximum tensile strength of 1022.32 ± 44.46 MPa (higher than other SA/PAAm hydrogels reported), elastic modulus of 481.04 ± 19.03 MPa and compression strength of 2.14 ± 0.11 MPa (only 0.47 ± 0.06 and 0.78 ± 0.05 MPa for SA/PAAm and SA/PAAm/Pal, respectively). The SA/PAAm/Pal-Fe hydrogel (diameter, 6 mm) can lift up weights over 8.45 kg. The high mechanical strength is resulting from the synergy of multiple crosslinked networks, which are favorable to the energy transfer or dissipation of hydrogel during stretching or compression, and thus form stronger and fracture-resistant hydrogel.