Electrospinning process for manufacture of multi-layered structures
Devices and methods for high-throughput manufacture of concentrically layered nanoscale and microscale fibers by electrospinning are disclosed. The devices include a hollow tube having a lengthwise slit through which a core material can flow, and can be configured to permit introduction of sheath material at multiple sites of Taylor cone formation formation.
1. A method of forming a structure, the structure comprising a core including a first material and a sheath including a second material around said core, the method comprising the steps of:
providing an apparatus, comprising:
a first wedge-shaped vessel having a first slit and comprising an electrically conductive material;
a second wedge-shaped vessel having a second slit, wherein the first wedge-shaped vessel is disposed inside of the second wedge-shaped vessel;
first and second fluid reservoirs containing the first and second materials, respectively, wherein the first and second fluid reservoirs are in fluid communication with the first and second wedge-shaped vessels, respectively; and
a voltage source configured to apply a voltage to at least one of the first and second materials;
activating the voltage source to apply a voltage of between 1 and 250 kV;
moving the first material from the first fluid reservoir to the first wedge-shaped vessel; and
moving the second material from the second fluid reservoir to the second wedge-shaped vessel.
2. The method of claim 1 , wherein the structure is an elongate fiber.
3. The method of claim 1 , wherein the apparatus includes a collecting area having at least one electrically grounded point thereon, the method further comprising the step of collecting the structure within the collecting area.
4. The method of claim 1 , wherein the step of moving the first fluid from the first fluid reservoir to the first wedge-shaped vessel includes supplying a gas to the first fluid reservoir at a substantially constant pressure.
5. The method of claim 1 , wherein the step of moving the first fluid from the first fluid reservoir to the first wedge-shaped vessel includes moving a piston within the first fluid reservoir at a constant rate.
6. The method of claim 1 , wherein the step of moving the second fluid from the second fluid reservoir to the second wedge-shaped vessel includes moving a gas into the second fluid reservoir at a substantially constant pressure.
7. The method of claim 1 , wherein the step of moving the second fluid from the second fluid reservoir to the second wedge-shaped vessel includes moving a piston within the second fluid reservoir at a substantially constant rate.
8. The method of claim 1 , wherein the voltage applied in the step of activating the voltage source is between 1 and 100 kV.
9. The method of claim 1 , wherein the first slit is positioned at an apex of the first wedge-shaped vessel.
10. The method of claim 9 , wherein the second slit is positioned at an apex of the second wedge-shaped vessel.
11. The method of claim 10 , wherein the first and second slits are aligned.
12. A method of forming an elongate fiber, the elongate fiber comprising a core including a first material and a sheath including a second material around said core, the method comprising the steps of:
providing an apparatus, comprising:
a first wedge-shaped vessel having a first slit and comprising an electrically conductive material;
a second wedge-shaped vessel having a second slit, wherein the first wedge-shaped vessel is disposed inside of the second wedge-shaped vessel;
first and second fluid reservoirs containing the first and second materials, respectively, wherein the first and second fluid reservoirs are in fluid communication with the first and second wedge-shaped vessels, respectively;
a voltage source configured to apply a voltage to at least one of the first and second materials; and
a collecting area having at least one electrically grounded point thereon;
activating the voltage source to apply a voltage of between 1 and 250 kV;
moving the first material from the first fluid reservoir to the first wedge-shaped vessel;
moving the second material from the second fluid reservoir to the second wedge-shaped vessel; and
collecting the elongate fiber within the collecting area.
13. The method of claim 12 , wherein the step of moving the first fluid from the first fluid reservoir to the first wedge-shaped vessel includes supplying a gas to the first fluid reservoir at a substantially constant pressure.
14. The method of claim 12 , wherein the step of moving the first fluid from the first fluid reservoir to the first wedge-shaped vessel includes moving a piston within the first fluid reservoir at a constant rate.
15. The method of claim 12 , wherein the step of moving the second fluid from the second fluid reservoir to the second wedge-shaped vessel includes moving a gas into the second fluid reservoir at a substantially constant pressure.
16. The method of claim 12 , wherein the step of moving the second fluid from the second fluid reservoir to the second wedge-shaped vessel includes moving a piston within the second fluid reservoir at a substantially constant rate.
17. The method of claim 12 , wherein the voltage applied in the step of activating the voltage source is between 1 and 100 kV.
18. The method of claim 12 , wherein the first slit is positioned at an apex of the first wedge-shaped vessel.
19. The method of claim 18 , wherein the second slit is positioned at an apex of the second wedge-shaped vessel.
20. The method of claim 19 , wherein the first and second slits are aligned.