Application Cases

Experiment Name: Research on Fabrication of Flexible Pressure Sensors Based on EHD Electrospinning

Research Direction: EHD electrospinning is a novel 3D printing technology that has gained attention due to its high precision, simple operation, wide material availability, and low cost. It has broad application prospects in flexible electronics, biomedicine, and wearable devices.

Experiment Purpose: To build a high-resolution electrospinning 3D printing experimental platform, initially verify theoretical and numerical simulation accuracy on glass slides, and then study the impact of process parameters (voltage, air pressure, printing speed) on the formation of printed silver nanowire conductive ink on PET films.

Testing Equipment: High-voltage amplifier, arbitrary waveform signal generator, high-precision smart voltmeter, switch power supply, etc.

Figure: Block Diagram of the EHD Electrospinning Experimental Platform System

Figure: Structural Schematic Diagram of the EHD Electrospinning Experimental Platform

Experiment Process:

A three-dimensional motion control system was set up. The voltage control system was built with a high-voltage amplifier, arbitrary waveform signal generator, high-precision smart voltmeter, and switch power supply. The liquid supply system was constructed with a nozzle and a material reservoir. The pneumatic system included a diaphragm vacuum pump, air pressure controller, air tubes, and a dispensing adapter tube. An image acquisition system was set up with a USB electron microscope and an optical microscope.

Experimental Steps:

(1) Install the dispensing needle on the cartridge and inject silver nanowire conductive ink into the cartridge with a syringe.

(2) Adjust the Z-axis height of the three-dimensional motion platform via the upper computer control interface to set the distance between the conductive nozzle and the receiving substrate to 0.5 mm.

(3) Connect the air tube to the dispensing adapter tube, turn on the diaphragm vacuum pump and air pressure regulator, adjust the air pressure to the required value, and wait for the pressure to stabilize.

(4) Connect the voltage output end of the voltage control system to the dispensing nozzle, ensure reliable wiring, good grounding of the printing platform, and keep the dispensing nozzle away from metal equipment to avoid external interference.

(5) Connect the USB electron microscope to the upper computer and adjust the microscope distance to clearly observe the nozzle area.

(6) Turn on the power switch of the voltage control system's instrument box, then sequentially open the panel switches, the arbitrary waveform signal generator switch, and the knob switch. Set the output waveform of the arbitrary waveform signal generator and output it.

(7) Place the receiving substrate coated with silver nanowire ink in a drying box at 140°C for 30 minutes to observe the deposition state.

Experimental Process Parameters:

The distance between the conductive nozzle and PET is 0.5 mm. The amplitude of the AC pulse voltage is 1300 V, the frequency is 500 Hz, and the duty cycle is 50%. The applied air pressure is 8 mmHg.

Figure 3: Comparison of Printed Conductors at Different Printing Speeds

Figure 4: Scatter Plot of Conductor Width vs. Printing Speed

Experimental Results:

A high-resolution electrospinning 3D printing experimental platform was designed and built. The platform has a high motion precision of 0.05 mm, with effective travel ranges of 30 cm for the X and Y axes and 20 cm for the Z axis. By printing silver nanowire conductive ink on glass slides, the impact of direct current voltage and air pressure on the conical jet shape was studied, and the same conclusions as theoretical analysis and simulation results were obtained. By electrospinning silver nanowire conductive ink on PET films, the impact and patterns of printing voltage, air pressure, and printing speed on the printed patterns were studied. The optimal process parameters were found to be an AC pulse voltage amplitude of 1300 V, frequency of 500 Hz, duty cycle of 50%, air pressure of 8 mmHg, and printing speed of 24 mm/s. Under these parameters, the printed silver nanowire conductor has a minimum width of 100 μm.

Power Amplifier Recommendation: ATA-7020

Figure: Specification Parameters of the ATA-7020 High-Voltage Amplifier