Fabrication Of Ultra-thin Elastomer Film Strain Sensor And Its System Application

Strain sensors,devices that transform strain gauge into electrical signal,are widely used in monitoring infrastructure constructions.The commercial solutions for infrastructure constructions are usually based on metal gauge sensors,which are too large and not sensitive enough for wearable applications.With the rise of Internet of Things and wearable devices,the research of strain sensors becomes more and more interested in devices with small shape,good transparency and ability to attach to human body.Here we present strain sensors of high sensitivity and excellent transparency which were fabricated based on an thin film(~20 ?m)poly(dimethylsiloxane)(PDMS)elastomer film integrating a conductive composite of silver nanowires and neutral-pH poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate).Such a thin PDMS film was peeled off from a glass substrate,which surface was modified with 1H,1H,2H,2H-per-FluoroOctylTrichloroSilane(FOTS)to reduce the required tensile stress in the elastomer film for the peeling-off process.The thin film sensor presented a sensitivity more than 20 times higher than that of strain sensors based on a thick(800 ?m)PDMS film,and also a high optical transparency of nearly 80%,which are desired features for developing unperceivable and invisible sensors in wearable applications.An application for real-time monitoring of human neck posture was finally demonstrated.The transparent thin film strain sensor was attached to human neck to sample strain gauge,while an embedded data acquisition board(DAQ board)collected gauge data and transported data to users' smart phones for display and storage.The neck posture monitoring system monitors human neck posture precisely and reminds users of unhealthy posture and can be equipped without discomfort.The thin film strain sensor,whose features meet the desires for human health monitoring very well,was proved of great potential in wearable applications.