聚丙烯腈/二硫化钼复合薄膜的挠曲电效应分析及其应用

Analysis of flexoelectric effect of polyacrylonitrile/MoS_(2)composite film and its applications

复合薄膜中挠曲电材料的质量分数对薄膜的挠曲电效应影响显著,为探究聚丙烯腈(PAN)/MoS_(2)复合薄膜中MoS_(2)质量分数对其挠曲电压及挠曲电系数的影响规律,采用静电纺丝方法制备PAN/MoS_(2)复合薄膜,借助扫描电子显微镜和X射线衍射仪对复合薄膜的结构、形貌、元素组成等进行表征,基于悬臂梁方法测试不同MoS_(2)质量分数对PAN/MoS_(2)复合薄膜挠曲电效应的影响,通过间歇式挠曲电效应测试检测复合薄膜的稳定性。结果表明:挠曲电压和挠曲电系数随着MoS_(2)质量分数的增大而提高,且在MoS_(2)质量分数为50%时挠曲电压和挠曲电系数达到最优,分别为0.8 V和1.96 nC/m;该薄膜的挠曲电效应稳定性优异,串联多个PAN/MoS_(2)复合薄膜可获得较高的挠曲电压,且电压衰减极弱,可广泛适用于微小型可穿戴电子设备。

Objective In recent years,flexible electronic devices and smart clothing have been developed rapidly.However,traditional batteries are difficult to meet the practical needs of portability and integration of flexible products.Therefore,there is a demand on the development of flexible energy devices suitable for flexible wearable electronics.Flexoelectricity is an electromechanical coupling effect that converts mechanical energy into electrical energy through the flexural deformation of thin films,thereby powering flexible and wearable electronic devices.molybdenum disulfide(MoS_(2))and polyacrylonitrile(PAN)composite films have good flexoelectric response,however,the factors affecting the flexoelectric voltage and flexoelectric coefficient are still to be studied.Method In this study,the PAN/MoS_(2)composite film will be prepared by electrospinning,and the structure,morphology and elemental composition of the composite film will be characterized by scanning electron microscope and X-ray diffractometer.The influence of different mass fractions of MoS_(2)on the flexoelectric effect of PAN/MoS_(2)composite films was tested through the method of cantilever beam.The flexoelectric stability of the composite films was also examined by intermittent flexoelectric testing.In addition,this paper reported a high flexoelectric voltage generated by connecting multiple composite films in series,which is applicable to micro-miniature wearable electronic devices.Results The characterization of composite films fully demonstrated that MoS_(2)was successfully loaded on the PAN fiber with good crystallinity,understanding that pure PAN film exhibits a weak flexoelectric effect.After adding MoS_(2)to the film,the flexoelectric voltage and flexoelectric coefficient of the composite film were increased with the increase of mass fraction of MoS_(2),and the optimum values were obtained when the mass fraction of MoS_(2)was 50%,which were 0.8 V and 1.96 nC/m,respectively.Continuously increasing the content of MoS_(2)in the composite film,the flexoelectric coefficient and flexoelectric voltage of the film were decreased rapidly.This is mainly because when the mass fraction of MoS_(2)was high,clusters were easy to appear,and this would seriously hinder the orderly arrangement of molecular chains,thereby limiting the excursion of positive and negative electrons and inhibiting the flexoelectric effect.The flexoelectric test was carried out every other day,and the test duration was 5000 s.During the continuous 7 d test,the flexoelectric voltage was about 0.8 V,and the consistency of the voltage value was good,indicating stable the flexoelectric effect of the PAN/MoS_(2)composite film.In addition,multiple PAN/MoS_(2)composite films with 50%MoS_(2)mass fraction were connected in series and packaged.The flexoelectric voltage of a single composite film was about 0.8 V,and the flexoelectric voltages of 3 and 5 composite films in series were 2.3 V and 3.8 V,respectively.Connecting multiple PAN/MoS_(2)composite films in series obtained high flexoelectric voltage with little voltage attenuation.Experiments proved that the flexoelectric effect obtained by mechanical flexural deformation could almost meet the needs of tiny wearable electronic devices.Conclusion The PAN/MoS_(2)composite film was prepared by electrospinning,and MoS_(2)nanoparticles were successfully loaded on the surface of PAN fibers.The mass fraction of MoS_(2)in PAN/MoS_(2)composite film has a significant effect on its flexoelectric effect.Experiments show that when the mass fraction of MoS_(2)is less than 50%,the flexoelectric voltage and flexoelectric coefficient increase with the increase of mass fraction of MoS_(2),when the mass fraction of MoS_(2)reaches 50%,the optimal flexoelectric voltage and flexoelectric coefficient can be obtained,and when the mass fraction of MoS_(2)exceeds 50%,the MoS_(2)particles will cluster and weaken the flexoelectric effect.The composite film prepared in this paper has excellent flexoelectric stability through intermittent flexoelectric test.The experimental results show that connecting the composite films in series can obtain high flexural voltage with extremely weak voltage attenuation,which can meet the needs of tiny flexible wearable electronic devices.