Electrospining Machine: Professor Chuhong Zhang, Sichuan University et al. Small Methods: Electrostatically Spun Highly Bidirectional Flexible Piezoelectric Electrospun Nanofbers for Anisotropic Response Smart Sensing

Background

Flexible piezoelectric energy harvesters (PEHs) have attracted much attention due to their wearability, breathability and sustainable self-powering. However, existing thin-film PEHs are unable to recognise forces in different bending directions, limiting their applications in wearable electronics and artificial intelligence.

In view of this, Professor Zhang Chuhong and Associate Professor Liu Xinguang of Sichuan University prepared highly bi-oriented flexible piezoelectric Electrospun Nanofibers for Anisotropic-Responsive Intelligent Sensing by electrospinning technology. The related research results are published under the title of ‘Electrospinning of Highly Bi-Oriented Flexible Piezoelectric Nanofibers for ’Anisotropic-Responsive Intelligent Sensing.The research results were published in the journal Small Methods.

The main point of this paper

1.It was studied that piezoelectric anisotropic BaTi2O5 nanorods (BT2-nr) were introduced into piezoelectric poly(vinylidene fluoride) (PVDF) Electrospun Nanofbers with biaxial structure for the first time, and during the electrospinning process, the BT2-nr were uniformly aligned in the PVDFElectrospun Nanofbers During the electrospinning process, BT2-nr was uniformly arranged in the PVDF Electrospun Nanofbers, and fabric PEH was constructed.

2. The bi-orientation property makes the flexible PEH anisotropic, which can sensitively identify the force in different bending directions (e.g., perpendicular bending, parallel bending, or twisting 45° along the fibre direction).

3.  Meanwhile, the composite PVDF/BT2 PEH containing 15 wt.% BT2-nr provided an optimal piezoelectric output of 31.2 V with a high sensitivity of 5.22 V N-1. The developed anisotropic PEH can be used as a self-powered pressure sensor for multimodal intelligent biomonitoring of human movement.

Electrospinning method for the preparation of PVDF/BT2 composite Nanofiber Membrane Steps.

1.Preparation of PVDF/BT2 Electrospun Nanofbers: 

BT2 nanorods were prepared by molten salt synthesis.PVDF particles were dissolved in a solvent mixture of DMAC and acetone to form a homogeneous solution. Different contents of BT2 (0, 5, 10, 15, 20 wt.%) were dispersed in the PVDF solution to form a uniformly dispersed spinning solution.

2.Electrospinning：

Spinning solution is sucked into a plastic syringe with a stainless steel needle. During the electrostatic spinning process, a high DC voltage is applied to the needle and the collector. By controlling the rotational speed of the drum collector, random or aligned PVDF/BT2 composite Electrospun Nanofbers can be obtained.

3.Drying: 

The PVDF/BT2 Electrospun Nanofbers were dried in a vacuum oven at 70°C for 10 hours to remove residual solvents.

Optimised piezoelectric energy harvesters have the following potential applications

1. Self-powered pressure sensor: 

The piezoelectric energy harvester can be used as a self-powered pressure sensor for multimodal smart biomonitoring of human movement. It can sensitively recognise forces in different bending directions and is suitable for wearable piezoelectric pressure sensors.

2. Wearable Bioelectronic Devices:

The piezoelectric energy harvester can be integrated into wearable bioelectronic devices to help people assess their physical condition and sense their surroundings. Its wearability, breathability and sustainable self-powered nature make it suitable for such applications.

3. Artificial Intelligence: 

The piezoelectric energy harvester can be used in the field of artificial intelligence for sensing biomechanical movements and enabling human-computer interaction. It can monitor human activities such as finger recognition, physiological movements and speech recognition.

Overall, the optimised piezoelectric energy harvester provides a viable strategy for fabricating self-powered flexible piezoelectric energy harvesters with high electro-mechanical conversion efficiency and versatility for a variety of applications such as wearable electronics, artificial intelligence, and smart biomonitoring.

Originallink: https://doi.org/10.1002/smtd.202300701