WIRE SPINNERETS

During the electrospinning process, the high voltage was applied to the stationary wires and a polymer solution was loaded on the surface of the wires by moving the wire through the polymer solution. Then, numerous jets were generated from the wire surface. It has a better spinning performance than the previous version, which use a rotating drum as spinneret.

CLEFT SPINNERET

Lukas et al. reported an electrospinning setup that used linear clefts as the spinneret (Fig. 7.6). The authors also developed a one-dimensional electrohydrodynamic theory to explain the process of electrospinning conductive liquids from an open plane surface (Fig. 7.6). During the electrospinning process, the amplitude of characteristic wavelength grew faster because of the electrical force. The fastest-growing stationary wave marked the onset of electrospinning from a free liquid surface. This theory not only predicated the critical value of the electrospinning process but also explained the upward needle-less electrospinning.

MAGNETIC FLUID

In 2004, Yarin and Zussman reported a needle-less electrospinning system that used a magnetic field to initiate the jet formation. The setup comprised a bottom layer of ferro magnetic fluid and an upper layer of polymer solution (Fig. 7.4A). When an external magnetic field was applied to the fluid system and an electric field was added simultaneously to the polymer solution layer, the ferromagnetic fluid triggered the formation of steady vertical spikes, which perturbed at the interlayer interface. Under the action of a strong electric field, these spikes were drawn into fine solution jets (Fig. 7.4B). Compared with multineedle electrospinning, this needle-less setup can produce polyethylene oxide (PEO) nanofibers with 12 times higher productivity. Nevertheless, the nanofibers electrospun are relatively coarser with larger diameter distribution.

Needle-less Electrospinning

Needle-less electrospinning appeared in the early 1970s, when Simm and coworkers filed a patent on using an annular electrode to electrostatically spin fibers for filtration appli cations. Next, Lukas et al. investigated the self-organization of charged jets initiated from the open free-liquid surface in the electrospinning process. Lin and colleagues developed a rotating spiral coil spinneret, which had a high fiber production rate with well-controlled fiber morphology. Liu et al. electrospun nanofibers by blowing air into the polymer solution. The bubbles generated assisted in jet initiation. Since 2008, growing research has been devoted to needle-less electrospinning. Research publications have been increasing constantly over the years. Over 100 articles about needle-less electrospinning or free-surface electrospinning have been published since 2007. The publication number between 2014 and 2016 was approximately 10 times more than that of 2007e2013 (Fig. 7.2A). Research is widespread in many countries. China, Australia, and the Czech Republic take about 80% of publications, followed by the United States, Germany, and England (Fig. 7.2B).

Multineedle Electrospinning Apparatus

Nanofiber yarn is defined as a twisted nanofiber bundle or tow featuring a morphology that is similar to filament yarn or spun yarn. Nanofiber yarn is mechanically suitable for weaving, knitting, and other methods used to produce fabrics. He and colleagues succeeded in producing continuous and twisted polyacrylonitrile nanofiber yarns by using a four-nozzle bubble electrospinning method, and the twist of the prepared nanofiber yarn could be adjusted by controlling the rotational speed of the collecting device, as shown in Fig. 6.13A and C. Two pairs of nozzles were positively and negatively charged, and the metal funnel collector was not grounded. After voltage was applied, the conjugate electric field came into being between the positive and the negative nozzles; however, the metal funnel located in the middle of the two groups of nozzles would have charges that were opposite those of the nearby charged nozzles. Therefore, induction fields were created between both edges of the funnel and their nearby charged nozzles. The electronic field lines were mainly distributed between the positive and the negative nozzles, and between the nozzles and the edge of the funnel. Because of the

Efficient Needle-free Electropinning Nanofiber Production Line MF01-003 ...

Qingzi Nano’s MF01 is an equipment of series of nanofiber production line, including needle spinning( MF01-001 and MF01-002) and needle-free spinning (MF01-003 and MF01-004) series. It is based on electrospinning technology to produce nanofiber membrane in high efficiency and quantity production, which can meet the growing need for nanofiber applications and achieve industrial benefits.

Features:

1. Quickly manufacture sample;
2. Automatic roll-to roll system;
3. Temperature and humidity controllable fabrication;
4. Nanofiber membrane drying system;
5. Safeguard system;

 Parameters:

1. Number of spinning electrode: 2;
2. Spinning electrode width: 600mm;
3. Effective width of nanofiber layer: 250-600mm;
4. Speed of roll-to-roll: 0-5m/min;
5. Feeding system: corrosion resistance, high-voltage resistance;
6. Power supply: 220V 50Hz.

Near Field Direct Writing Electrospinning Equipment M08 Spinning Process

Features: 

1. -Printing resolation less than 50nm;
2. -Nanofiber highly oriented and controllable;
3. - International R & D team pioneering technology;
4. - Exclusive patented technology;
5. -Micro nano manufacture excellent tools

Near Electrospinning Technology Classification

Solution Near-field Electrospinning

Solution near-field electrospinning process, the printing material is prepared into a solution, and using electrostatic field print orientation nanofibers. It can produce a fiber orientation controllable fiber diameter range is 50nm-20μm, the solution electrospun near-field have more suitable materials.

Melt near-field electrospinning

Melt Near-field electrospinning process, the printed material is heated and melted, assisted with the electrostatic field, fibers with a diameter range of 500nm-50μm can be prepared, high 3D printing capability, very suitable for producing three-dimensional biological tissue engineering scaffolds.

Near field electrospinning equipment parameters

1. High voltage power supply: 0-30kv, adjustable;
2. Solution spinning nozzle: solution supply volume at least 10μl/h;
3. Melt spinning nozzle: nozzle temperature: 0-300℃, adjustable, precision pneumatic extrusion;
4. Printing environment temperature: indoor temperature -50℃, adjustable;
5. Collection platform: printing range 150*150mm, platform speed: 0-200mm/s, resolution: 50nm;
6. Nozzle height: 0-80mm, adjustable, resolution: 50nm;
7. Printable materials: PE0, PVA, PLA, PCL, PLGA, chitosan, sodium alginate, collagen, hydroxyapatite, PVDF and other hundreds of organic or inorganic materials;
8. printable user-defined patterns;
9. printable 3D structure;
10. customizable : temperature controllable collector;
11. customizable : multi-nozzle device.

Single-bubble Electrospinning Unit

The structural diagram of a single-bubble electrospinning unit is shown in Fig. 6.7. Bubbles are formed on the mouth of the nozzle during the experimental process, and the forces on the charged bubbles are the electric field force (Fe), the force caused by the difference in air pressure inside and outside of the bubbles (Fp), and the surface tension of the bubbles (Ft) after voltage application. The bubble film composed of the spinning solution is drawn and then ruptured into multijets when the electric field force exceeds Fp and Ft. Finally, the multijets are stretched into nanofibers via the electric force. Bubbles can be continually formed on the mouth of the nozzle, and each bubble bursts to form high-speed multiple jets. The squirting speed of the air is controlled to increase nanofiber yield. The nanofiber yield is as high as 2.352 g/h, which is far greater than the yield achieved by conventional single-needle production.

Multi-needle Nanofiber Electrospinning Production Line MF01-001 Spinning...

Qingzi Nano’s MF01 is an equipment of series of nanofiber production line, including needle spinning( MF01-001 and MF01-002) and needle-free spinning (MF01-003 and MF01-004) series. It is based on electrospinning technology to produce nanofiber membrane in high efficiency and quantity production, which can meet the growing need for nanofiber applications and achieve industrial benefits.

Features:

1. Automatic roll-to roll system;
2. Precious feeding system;
3. Multi-needle electrospinning systems;
4. Temperature and humidity controllable;
5. Nanofiber membrane drying system;
6. Safeguard system;

Parameters:

1. Needle Qty: 256, or more( customizable);
2. Roller speed:0-20m/min, adjustable;
3. Feeding system: corrosion resistance, high-voltage resistance;
4. Continuous operation time:≥8 hours;
5. Power supply: 380V;
6. Effective width of nanofiber layer: 660mm, or other( customizable).