Construction And Sensing Properties Of Flexible Piezoelectric Nanofiber Materials

Pressure sensors have important applications in the field of wearable electronic devices,microelectronic devices,and bionic robots.The development of flexible piezoelectric sensing materials is the basis of micro-pressure sensors.Piezoelectric polymers have attracted considerable attention on account of their excellent flexibility,high deformability,and easy processing.Although studies on piezoelectric polymers based flexible sensors have made great progress,a big challenge of piezoelectric materials application in micro-scale sensing systems is to address the restrictions of electrode compatibility,miniaturization,multistep assembly,and high cost.However,most of them necessitate a pair of top and bottom planar electrodes to implement piezoelectric sensing systems,air gaps often occur between the surface of functional elements and electrodes that affect electromechanical conversion efficiency.Therefore,a simple strategy is highly desired to explore flexible integrated piezoelectric sensing materials.Here,we propose a strategy to realize the construction of piezoelectric-conductive integrated sensing materials by fabricating[polyacrylonitrile]//[polyaniline/polyvinyl pyrrolidone]([PAN]//[PANI/PVP])Janus nanofibers(NFs),polyaniline/polyacrylonitrile(PANI/PAN),[polyvinyl pyrrolidone/polyaniline]//[polyacrylonitrile/barium titanate]([PVP/PANI]//[PAN/BTO])by electrospinning technology,respectively.The integrated piezoelectric sensing materials were characterized by SEM,TEM,EDS,XRD,and FTIR.The piezoelectric output performance of the samples was systematically studied and evaluated by simple packaging.The results show that the integrated material can directly generate and output voltage signals for pressure sensing under different forces based on the principle of the Wheatstone bridge,and the integrated structure is conducive to the collection of induced charges so that the material has a low-pressure detection limit(0.1 N)and high linear sensitivity.At the same time,the conductive-piezoelectric nanoresistance networks can be used as a new viable alternative material to sensor arrays and dot-matrix electrodes of the traditional device to realize force locating by detecting output voltages distribution of each section.In addition,the multifunctional sensing performance of the integrated piezoelectric sensing material was also explored.The above experimental results demonstrate the excellent properties of the piezoelectric-conductive integrated materials,which are expected to be applied in the fields of wearable pressure sensors and portable electronic devices.Taken together,our research provides a new method to synchronously construct piezoelectric materials and nanoresistance networks.A series of flexible nanofiber piezoelectric sensing materials are designed and prepared to realize the simultaneous construction of piezoelectric materials and nanoresistance networks,which overcomes the limitations of the traditional rigid electrode of a piezoelectric sensor,expands the application range of the piezoelectric material,and realizes the pressure positioning and multifunctional application of integrated sensing materials.The integrated sensing materials have potential applications in the fields of touch sensing,smart fabric,removable electronic skin for humanoid robotics,and electronic skin.