PVDF纳米纤维在微流体中的压电能量收集特性研究

Piezoelectric energy harvesting performance of PVDF nanofibers in microfluidic conditions

供电系统尺寸过大、寿命较短且需频繁充电的问题已成为当前无线传感和物联网领域亟待解决的关键问题。基于压电纳米材料的微型能量收集器件可将环境中富余的机械能高效地转换成电能,构建自供电的无线传感系统。本文采用静电纺丝技术制备高长径比聚偏氟乙烯(PVDF)压电纳米纤维,通过调整静电纺丝过程中前驱体溶液的浓度实现了对纳米纤维压电?物相含量的调控。结果表明,压电?相的含量会随着前驱液浓度的增加而提高,在浓度为0.13 g/m L时达到最大。当浓度进一步增加,?相含量逐渐降低。所得PVDF纳米纤维能量收集器件具有良好的压电发电性能,在外力作用下可产生约1.6 V的脉冲电输出。将PVDF纳米纤维与微流控芯片进行集成,通过采集液滴流动时所产生机械能,实现了连续的动态压电输出,输出电压峰峰值约为0.2 V。这种液相环境中对流体机械能的高效采集有望推动压电纳米纤维能量收集器件在微流控传感系统中的应用。

The power supply units in wireless sensor systems and internet of things are suffering from several critical problems,including large size,short lifetime and requirement of recharging.The microscale energy harvesters based on piezoelectric nanomaterials can convert the mechanical energy in the environment into electrical power,which can be utilized for building self-powered wireless sensor systems.In this work,the PVDF piezoelectric nanofibers with high aspect ratio were synthesized through electrospinning method.The content of?-phase in the PVDF nanofibers can be controlled by modifying the precursor concentration of the electrospinning method.The results suggest that the content of piezoelectric?-phase is increased to the highest level by increasing the precursor concentration to 0.13 g/mL.The further increase of precursor concentration leads to the decrease of content of?-phase.The flexible energy harvester based on the PVDF nanofibers exhibites outstanding piezoelectric power generation performance,which can generate output voltage with amplitude up to 1.6 V under the external stimulations.The piezoelectric PVDF nanofibers can be integrated with the microfluidic chips.The microfluidic device can realize the continues piezoelectric output by harvesting the mechanical energy from the flowing droplets.The peak-to-peak value of the output voltage was about 0.2 V.Such high-efficiency energy harvesting in liquid conditions may promote the development and application of piezoelectric nanofiber energy harvesters in microfluidic sensing systems.