An ultrasound-induced MXene doped PAM–SA super-tough hydrogel

Abstract

Here we reported a novel ultrasound-induced polymerization to achieve a polyacrylamide–sodium alginate (SA) dual network hydrogel via a redox reaction with MXene (Ti₃C₂) as a reductant and potassium persulfate (KPS) as an oxidant. Polymerization of acrylamide was carried out at 15 °C for only 5 min with a mass ratio of MXene:KPS of 1/10, and the hydrogel was further immersed in a 10 wt% CaAc₂ solution for 1.5 h. Super-toughness (elongation at break of 1728% and toughness of 2633.7 KJ m⁻³) and excellent conductivity (up to 3.5 S m⁻¹) were achieved, mainly due to coordinated regulation of MXene and Ca²⁺. MXene also acted as a crosslinker to effectively transfer the stress to polymer chains under the external force. The secondary cross-linking was achieved by the dynamic complexation between –COO⁻ of SA and the continuously released Ca²⁺ from CaAc₂. The strategy employed in this paper will be helpful to prepare intelligent flexible strain sensors.