Preparation And Properties Of Polysaccharide Thickened Nanocomposite Hydrogel

Flexible wearable sensors are becoming smart tools which can be used to collect signal information from the human body and the surrounding environment with smart,friendly and real-time characteristics.Therefore,flexible sensors showed great potential in various applications of modern electronic technology.As a classic soft material,hydrogel had become an important material in the field of tissue engineering and biosensing because of its good biocompatibility and excellent mechanical properties.In the field of wearable devices,however,traditional carbon-based nanocomposite hydrogels usually exhibit weak displacement performance and mechanical strength,which limit the reliability and sensitivity of hydrogel flexible sensors in practical applications.In order to solve the above problems,this paper designs a strategy based on multi-element thickening of reduced graphene oxide nanocomposite hydrogel,which has both viscous energy and rapid response.Strain sensitivity and other characteristics,and then carried out detailed research for the application as a flexible strain/pressure sensor.Here,we introduced gum arabic into the reduced graphene oxide/polyacrylamide cross-linked network system to prepare an adhesive nanocomposite hydrogel.The network formed by hydrogen bonding between gum arabic and polyacrylamide chains and the polyacrylamide chemical cross-linking network constitute a hybrid network,and these hydrogen bonding significantly increase the mechanical properties and fatigue resistance of the hydrogel.The fracture strain was 188.7 kPa and 2094.3%,and the toughness is 1165.3kJ/m~3.The hydroxyl group on the gum arabic flexible chain can produce strong adhesion with different substrates(aluminum,titanium,silica gel,plastic,glass,polytetrafluoroethylene,etc.),and the maximum peel strength on the surface of the aluminum plate is 166.5 N/m.The addition of reduced graphene oxide could not only improve the mechanical strength of the hydrogel,but also endow the hydrogel with excellent electrical conductivity,with a conductivity of 0.001716 S/cm.Subsequently,based on the above characteristics,we prepared the hydrogel into a flexible strain/pressure sensor,which can be attached to various joints of the human body to monitor the macroscopic body movements of the human body,such as fingers,wrists,elbows,knees,etc.;it can also be used It can monitor small physiological commands such as breathing,facial expressions,and vocalizations,and can even be used to monitor pulse beats;in addition,it can also be used to make pressure sensors to monitor the body's movement status.Significantly,this sticky nanohydrogel sensor does not require additional bandages and tape to be attached to the skin,and does not cause delamination between the hydrogel sensor and the skin during repeated movements,thus affecting the sensitivity of the hydrogel sensor.This adhesive nanocomposite hydrogels combined adhesion,toughness,and conductivity.They were very suitable for making flexible sensors for monitoring human life movements.Since reduced graphene oxide ensures the stable conductivity of the adhesive nanocomposite hydrogel,the skin-attached nanocomposite hydrogel sensors with high sensitivity,fast response and wide detection range have been proven to be used to monitor various mechanical stimuli and human movements.The skin-attached hydrogel sensor with gum arabic adhesion was expected to have broad application prospects in electronic skin,human-machine interface and soft robotics.