Piezoelectric poly(vinylidene fluoride)(PVDF)has received considerable attention due to its ability of interconverting mechanical into electric energies and potential applications in wearable electronics.To achieve pi...Piezoelectric poly(vinylidene fluoride)(PVDF)has received considerable attention due to its ability of interconverting mechanical into electric energies and potential applications in wearable electronics.To achieve piezoelectricity,it is important to simultaneously control the formation of polar phases,crystallinity,and dipole alignments in PVDF-based films.Here we demonstrate that piezoelectricity can be obtained by directly hot-pressing PVDF films sandwiched between chitosan or cellulose films.The electrostatic interactions between PVDF and chitosan or cellulose enabled an exceptional high content of polar phases(β-andγ-phases)up to 90%and a measured piezoelectric charge coefficient d_(33)of up to-30 pC/N.This study provides a simple and low-cost approach for obtaining piezoelectric PVDF films used for sensors,actuators,and energy harvesters.展开更多
With the rapid development of internet of things,self-powered touch sensors made of piezoelectric fluorinated polymers have attracted significant interest because they can constantly convert mechanical energy into ele...With the rapid development of internet of things,self-powered touch sensors made of piezoelectric fluorinated polymers have attracted significant interest because they can constantly convert mechanical energy into electrical energy without external power supply.However,it is still challenging to fabricate fluorinated polymer films with good adhesion and high output performance with a large-scale and low-cost method while maintaining high transparency,which are extremely important for simultaneous optical detection and electromechanical transduction.In this work,we demonstrate that the incorporation of a molecular ferroelectric-dabcoHReO_(4)(DH)into poly(vinylidene difluoride)(PVDF)solution enables high-throughput and low-temperature processing of flexible and transparent piezoelectric films by scalable processing method.The effects of multiaxial DH are multiple.First,DH can trigger the phase transition of PVDF fromα-toβ-phase and realize the orderly orientation of PVDF,which guarantees higher piezoelectric performance without any additional electrical poling process.Second,the hydrophilic nature of DH can improve the adhesion properties of PVDF,which in turn improve the stability and durability of the devices.By optimizing the fabrication processes,the transmittance of the piezoelectric touch sensors based on PVDF films and Ag nanowires coated poly(ethylene terephthalate)electrodes can be higher than 94%.The piezoelectric voltage constant g;of the transparent films can reach to 1.2 V·m·N;,which is at least three times higher than the commercially available PVDF films obtained by stretching.These results indicate that the flexible piezoelectric sensors have potential applications in transparent electronic devices for mechanical sensing and energy harvesting.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51973150 and 21674076)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.19KJA320009)a Project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Piezoelectric poly(vinylidene fluoride)(PVDF)has received considerable attention due to its ability of interconverting mechanical into electric energies and potential applications in wearable electronics.To achieve piezoelectricity,it is important to simultaneously control the formation of polar phases,crystallinity,and dipole alignments in PVDF-based films.Here we demonstrate that piezoelectricity can be obtained by directly hot-pressing PVDF films sandwiched between chitosan or cellulose films.The electrostatic interactions between PVDF and chitosan or cellulose enabled an exceptional high content of polar phases(β-andγ-phases)up to 90%and a measured piezoelectric charge coefficient d_(33)of up to-30 pC/N.This study provides a simple and low-cost approach for obtaining piezoelectric PVDF films used for sensors,actuators,and energy harvesters.
基金financially supported by the National Natural Science Foundation of China(Nos.51973150,51473112 and 21674076)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.19KJA320009)a Project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘With the rapid development of internet of things,self-powered touch sensors made of piezoelectric fluorinated polymers have attracted significant interest because they can constantly convert mechanical energy into electrical energy without external power supply.However,it is still challenging to fabricate fluorinated polymer films with good adhesion and high output performance with a large-scale and low-cost method while maintaining high transparency,which are extremely important for simultaneous optical detection and electromechanical transduction.In this work,we demonstrate that the incorporation of a molecular ferroelectric-dabcoHReO_(4)(DH)into poly(vinylidene difluoride)(PVDF)solution enables high-throughput and low-temperature processing of flexible and transparent piezoelectric films by scalable processing method.The effects of multiaxial DH are multiple.First,DH can trigger the phase transition of PVDF fromα-toβ-phase and realize the orderly orientation of PVDF,which guarantees higher piezoelectric performance without any additional electrical poling process.Second,the hydrophilic nature of DH can improve the adhesion properties of PVDF,which in turn improve the stability and durability of the devices.By optimizing the fabrication processes,the transmittance of the piezoelectric touch sensors based on PVDF films and Ag nanowires coated poly(ethylene terephthalate)electrodes can be higher than 94%.The piezoelectric voltage constant g;of the transparent films can reach to 1.2 V·m·N;,which is at least three times higher than the commercially available PVDF films obtained by stretching.These results indicate that the flexible piezoelectric sensors have potential applications in transparent electronic devices for mechanical sensing and energy harvesting.