Preparation and performance analysis of CNC/GO/CNTs/PVA/SA-Ca2+ conductive hydrogels

Abstract

Flexible sensors have been widely used in the manufacture of smart wearable devices in recent years, which can monitor mechanical deformation and then convert the mechanical deformation into electrical signals, and the flexible wearable devices made of them can be used in human movement monitoring, health detection, and other fields. However, with the progress of society and the expansion of the application range of flexible sensors, their functions have gradually developed into multi-functional. As the core component of flexible sensors, conductive hydrogels also put forward higher requirements, which need to have the characteristics of self-recovery, fatigue stability, large strain, and high sensitivity. In this paper, the solid-phase esterification reaction of polyvinyl alcohol (PVA) and succinic acid (SA) was used to prepare a CNC/GO/CNTs/PVA/SA–Ca²⁺ composite solution by a one-pot method, and then CNC/GO/CNTs/PVA/SA–Ca²⁺ conductive hydrogels were prepared by a freeze–thaw method. The results showed that the chemical crosslinking between PVA and succinic acid increased the tensile strength of the hydrogel (0.2 MPa; 226%). With the addition of SA, the three-dimensional network structure of the hydrogels is more dense, and the sensitivity (GF = 4.55, 0–200%) and cycling stability are improved, which indicates that the prepared hydrogels have broad application prospects in the field of wearable flexible sensors.