Highly Elastic Silver Nanowire-Based Aerogels As Piezoresistive Sensors

Flexible wearable piezoresistive sensors are widely discussed because of their more important roles in emerging fields such as human motion detection,health care,and intelligent human-machine interaction.Silver nanowires(Ag NWs),one of sensing materials,have good electrical conductivity.In addition,the porous material aerogel usually has a fine microstructure and fatigue resistance.Therefore,Ag NWs and aerogels were assembled to prepare Ag NWsaerogel sensors with superior integral performance,which has important theoretical and application.In this paper,we have successfully obtained the bulk synthesis of one-dimensional Ag NWs with optimum aspect ratio,by introducing the polyol method and optimizing the appropriate purification techniques.And the study found that the best purification method is mixed with deionized water and ethanol cross-washing.Subsequently,Ag NWs were mixed with different concentrations of polyvinyl alcohol(PVA)solution to obtain precursors.The precursor solution was prepared in two-dimensional lamellar network structure under the action of ice crystal growth by oriented freeze-drying technology.Eventually,it was constructed into a threedimensional Ag NWs aerogel with low density and high strength.The above process achieved the cross-scale assemble from 1D to 3D.Based on that,Ag NWs aerogel piezoresistive sensors were then fabricated.The study showed the aerogel sensor,assembled with 10 mg/m L PVA solution,had the best balance of performance,exhibiting suitable hydrophobicity,high elasticity,high sensitivity,and faster response(200 ms).In the cyclic stability test results,the current signal remained essentially stable for 1000 cycles,and the stress retention value was 85%.In addition,the sensor has relative independence for different compression rates.The polydimethylsiloxane(PDMS)encapsulation of the sensor improved its flexibility and structure stability.And the test results exhibited a low energy loss coefficient(0.02).What’s more,the sensor has been successfully applied to detect many body movements,including finger joint flexion,elbow extension and wrist pulse,etc.Meanwhile,it can detect changes in external airflow.These aerogel piezoresistive sensors had the advantages of high stability,wide detection range,and facile manufacturing scalable technology,which provide a new strategy for the application of aerogel sensors in flexible wearable devices.