Preparation of tough and anti-freezing hybrid double-network carboxymethyl chitosan/poly(acrylic amide) hydrogel and its application for flexible strain sensor

In this paper, we fabricated a tough, anti-freezing (freezing point of − 25.5 °C) and ionic conductive carboxymethyl chitosan (CMCS)-based double-network (DN) hydrogel by a free radical polymerization and Al 3+ coordination. In greater detail, the PAM/CMCS-Al 3+ hydrogel was composed of Al 3+ -coordinated CMCS network and covalently crosslinked PAM network. The hybrid DN structure of PAM/CMCS-Al 3+ hydrogel gave rise to high mechanical properties (tensile strength up to 2.15 MPa, elongation at break up to 1741%, toughness of 13.2 MJ/m 3 and elastic modulus of 1.43 MPa) and good fatigue resistance. PAM/CMCS-Al 3+ hydrogel not only exhibited the capacity to conduct electricity via free ions, but also had good strain sensitivity (GF = 2.09, 0–200% strain and fast response time of 234 ms). Based on the high strain sensitivity, PAM/CMCS-Al 3+ hydrogel could be used to assemble a flexible strain sensor with the ability to precisely detect human motions.Kindly check and confirm the edit made in the title.We agree with the edit made in the title.