Preparation And Strain Sensing Properties Of Freezing-Tolerant And Tough Hydrogels

Until now,Ionic Conductive Hydrogels have been available as an alternative to conventional rigid conductors due to their inherent properties.It has also been of great interest for the fabrication of conductor materials for flexible devices.However,it is still a challenge to achieve high mechanical properties,toughness,sensing properties and freezing-tolerant at the same time using inexpensive raw materials and simple synthesis processes.Particularly for use under high latitudes,partial low and even sub-zero temperature states are inevitable.Conventional hydrogels,which have a high proportion of water inside,become brittle or even freeze at low temperatures and are unable to stretch and conduct electricity.It is therefore of great interest to design and manufacture a conductive hydrogel with a wide range of applications and excellent mechanical properties.High performance PVA/PVP/Glycerol/Na Cl/CMC(PPNGC)ionic hydrogel sensors are easy to fabricate and overcome these challenges.The proposed hydrogel sensor is based on biocompatible PVA,PVP and CMC,which are physically mixed in a glycerol-water solvent system and then prepared as a hydrogel by freeze-thawing.The hydrogel has good tensile properties,excellent mechanical strength and toughness of the Ionic Conductive Hydrogels.Compared to other reported freezing-tolerant Ionic Conductive Hydrogels,the Ionic Conductive Hydrogels have excellent freeze resistance due to the presence of glycerol and Na Cl,maintaining flexibility and electrical conductivity even at-40 degrees Celsius.At the meantime,the PPNGC Ionic Hydrogel sensor has good stretching and electrical conductivity,and can detect accurate electrical signals repeatedly and stably for both large and small strains.On the basis of these characteristics,the freezing-tolerant and tough PPNGC hydrogel sensor can be used as a wearable device for detecting human motion with high sensitivity,stability and durability,both at room temperature and at low temperatures.Thus,this prepared hydrogel,under wide range conditions,has the potential for practical application of high performance wearable strain sensors in bionic prostheses and human activity monitoring systems.