Preparation And Application Of Silver/Multilayer Graphene Composites

Silver is a kind of functional material with many excellent properties,and graphene can be used as the carrier of nano metal materials.Silver/graphene composites are widely used in flexible strain sensors due to their high electrical conductivity and good mechanical properties.At present,the reported preparation process generally uses the oxygen-containing functional groups on the surface of GO to adsorb silver ions and add reducing agents to prepare silver/graphene composites.However,GO is expensive and complex to prepare and cannot be mass-produced.Multilayer graphene is cheap and easy to prepare and can be prepared on a large scale.However,it is very difficult to directly deposit silver particles on the surface of multilayer graphene without oxygen-containing functional groups,and there is no research precedent for using silver/multilayer graphene composites to prepare strain sensors.In this paper,silver/multilayer graphene composites with good microstructure are prepared by using ultrasonic stripping multilayer graphene as silver carrier through process exploration.The flexible strain sensor is prepared by using this composite material and its performance was measured.The research contents are as follows:(1)Explore the effects of glucose,sodium acetate,reaction temperature and different dispersants on the microstructure of silver/multilayer graphene composites and the optimal preparation process.Using AgNO3 as silver source,glucose as modifier,ethylene glycol as dispersant,ascorbic acid as reducing agent,and anhydrous sodium acetate as particle size regulator,the silver particle/multilayer graphene composite is prepared by water bath method.The silver particle size distribution of the prepared composite is between 50nm and 150nm,and the deposition on the surface of multilayer graphene is uniform,and the utilization rate of silver source is high.(2)Investigate the effects of ammonia,sodium acetate,buffering stirring time at room temperature,reaction temperature and time,different dispersants on the microstructure of silver/multilayer graphene composites and the best preparation process.Silver nanoparticles/multilayer graphene composites are prepared by water bath method using AgNO3 and 28%concentration of ammonia as silver ammonia solution,ascorbic acid as reducing agent,anhydrous sodium acetate as particle size regulator.The silver nanoparticles in the prepared composite has a particle size distribution of 50nm～l00nm,and are evenly spread on the surface of multilayer graphene.The utilization rate of silver source is high.(3)The flexible strain sensor is prepared by coating process using silver/multilayer graphene composite with the best microstructure and waterborne polyurethane resin(WPU).The effects of different silver/multilayer graphene additions on the performance of the sensor were investigated.The optimal addition amount of silver/multilayer graphene composite material in the sensor is 40%,and the sensitivity coefficient of the sensor prepared can reach 304.1,the deformation range is 100%and the recovery is good.Meanwhile,the sensor has excellent wearable performance in the knuckle and wrist joints,and has extremely high practical value.