Low voltage near-field electrospinning method and device
An electrospinning method includes providing a nozzle fluidically coupled to a source of polymer ink and providing a substrate adjacent to the nozzle. A first voltage is applied to the nozzle to initiate electrospinning of the polymer ink onto the substrate, wherein the first voltage is within the range of about 400V to about 1000V. The voltage is then reduced to a second, lower voltage wherein the voltage is within the range of about 600V to about 150V.
1. An electrospinning method comprising:
providing a nozzle fluidically coupled to a source of polymer ink;
providing a substrate adjacent to the nozzle;
applying a first voltage to the nozzle to initiate electrospinning of the polymer ink onto the substrate, wherein the first voltage is within the range of about 400V to about 1000V;
reducing the voltage to a second, lower voltage wherein the voltage is within the range of about 600V to about 150V;
moving the substrate in at least one of the x, y, and z directions relative to the nozzle at different speeds so as to alter the diameter of polymer ink reaching the substrate; and
wherein the polymer ink comprises less than 3.0 (wt %) PEO having a molecular weight of about 4,000,000.
2. The method of claim 1 , further comprising moving the nozzle in at least one of the x, y, and z directions relative to the substrate.
3. The method of claim 1 , further comprising controlling at least one of the acceleration, deceleration, or speed of the substrate to cause a gradual change in the thickness of the electrospun ink.
4. The method of claim 2 , further comprising controlling at least one of the acceleration, deceleration, or speed of the nozzle to cause a gradual change in the thickness of the electrospun ink.
5. The method of claim 1 , wherein the distance between the nozzle and the substrate is within the range of about 1 mm and about 3 mm.
6. The method of claim 1 , wherein substrate moves relative to the nozzle such that the electrospun polymer can be further stretched mechanically.
7. The method of claim 1 , further comprising pyrolysing the polymer ink.
8. The method of claim 1 , wherein the polymer ink comprises high molecular weight PEO with an aqueous dispersion of PEDOT:PSS.
9. The method of claim 8 , wherein the polymer ink comprises between about 20% to about 30% (wt %) PEDOT:PSS dispersion concentration in 1.6-2.0 (wt %) PEO base solution.
10. The method of claim 1 , wherein the polymer ink comprises a photoresist.
11. The method of claim 10 , wherein the photoresist comprises a carbonizable negative photoresist.
12. The method of claim 11 , wherein the polymer ink further comprises gamma-Butyrolactone (GBL).