High voltage electrospinning, as an efficient technology for preparing nanofibers, has shown great potential in biomedical, filtration materials, energy storage and other fields due to its advantages of simple process, controllable fiber diameter (50nm-10 μ m) and wide material adaptability. This article systematically analyzes the basic principles of high-voltage electrospinning equipment from three aspects: the mechanism of electric field force, solution jet behavior, and fiber forming process.

　　1、 The mechanism of jet formation driven by electric field force

The core principle of high-voltage electrospinning equipment is to use a high-voltage electric field (usually 5-30kV) to charge polymer solutions or melts. When the electric field force overcomes the surface tension of the solution, a Taylor cone is formed and a charged jet is ejected. The physical process can be divided into three stages:

1. Charge accumulation stage

By inducing charge distribution on the surface of the solution through a high-voltage power supply, the surface charge density (σ) of the solution satisfies the relationship with the electric field strength (E): σ=ε₀ ε _rE, where ε₀ is the vacuum dielectric constant and ε _r is the relative dielectric constant of the solution. When the electric field force generated by surface charge (F_e=σ E) exceeds the surface tension of the solution (F_s=2 π r γ, where r is the droplet radius and γ is the surface tension), the droplet deforms into a Taylor cone.

2. Unstable stretching stage of jet flow

After leaving the Taylor cone, the charged jet undergoes bending instability due to the repulsion between charges, while the electric field force continues to stretch the jet, causing its diameter to plummet from hundreds of micrometers to nanometers in microseconds. During this process, the solvent evaporates rapidly or the melt cools and solidifies, forming primary fibers.

3. Fiber deposition and solidification stage

Charged fibers fly towards the collection plate under the action of an electric field. By adjusting the movement speed of the collection plate (0.1-10m/s) and the distribution of the electric field, the direction of fiber arrangement can be controlled. For melt spinning, precise control of the melt temperature is required to avoid fiber breakage.

　　2、 The influence of key process parameters on fiber morphology

1. Voltage intensity: An increase in voltage (10-25kV) can enhance the electric field force and reduce the fiber diameter, but excessive voltage (>30kV) can easily cause spark discharge and interrupt spinning;

2. Solution concentration: Low concentration (<5wt%) causes jet breakage, while high concentration (>20wt%) makes it difficult to form Taylor cone due to high viscosity;

3. Receiving distance: Increasing the distance (10-30cm) prolongs the solvent evaporation time and reduces fiber adhesion, but too long a distance will reduce the electric field strength and affect the stretching effect;

4. Environmental parameters: An increase in humidity (>60% RH) will delay solvent evaporation, resulting in uneven fiber diameter; Raising the temperature (25-60 ℃) can reduce the viscosity of the solution and promote spinning stability.

　　3、 Typical application scenario expansion

1. Biomedical: Preparation of polylactic acid (PLA) nanofiber scaffolds for cell adhesion and proliferation in tissue engineering;

2. Air filtration: PVDF nanofiber membrane was prepared by electrospinning, with a filtration efficiency of 99.97% for PM0.3;

3. Energy field: Using PAN based carbon nanofibers as negative electrode materials for lithium-ion batteries, the specific capacity is increased to over 500mAh/g.

High voltage electrospinning equipment achieves multi-scale structural control from micro to macro level by precisely regulating the electric field force and solution rheological behavior. With the breakthroughs in technologies such as multi needle arrays and near-field direct writing, their industrial application process is constantly accelerating.