Centrifugal electrospinning process
The present disclosure provides a fiber-forming process that includes: providing a centrifugal electrospinning apparatus that includes: an emitter that includes a rotating element having a rotational speed of 10,000 rpm or less; and a collector; and providing a spinning solution including at least one polymer dissolved in at least one solvent; supplying the spinning solution to the emitter; and directing the spinning solution from the emitter toward the collector under conditions effective to form separate fibrous streams from the spinning solution, vaporize the solvent, and produce polymeric fibers on the collector.
1. A fiber-forming process comprising:
providing a centrifugal electrospinning apparatus comprising:
an emitter comprising:
(a) a free-surface edge rotating at a rotational speed of between 1,000 and 4,000 rpm
(b) a discharge portion having a forward surface defining a concave shape including a perpendicular ring region; and
(c) a diffuser portion configured to mate with the discharge portion;
providing a collector;
providing a spinning solution comprising at least one polymer dissolved in at least one solvent;
supplying the spinning solution to the emitter; and
directing the spinning solution from the emitter toward the collector under conditions effective to form separate fibrous streams from the spinning solution, vaporize the solvent, and produce polymeric fibers on the collector.
2. The process of claim 1 further comprising providing a voltage potential of 40-80 kV between the emitter and the collector.
3. The process of claim 1 wherein the rotating element of the emitter has a rotational speed of 3500 rpm or less.
4. The process of claim 3 wherein the rotating element of the emitter has a rotational speed of 3000 rpm or less.
5. The process of claim 1 wherein the rotating element of the emitter has a rotational speed of at least 1000 rpm.
6. The process of claim 1 wherein the rotating element defines a forward surface facing the collector configured to discharge the spinning solution centrally therefrom.
7. The process of claim 6 wherein:
the forward surface is a concave forward surface and defines a forward surface discharge edge; and
the step of issuing the spinning solution from the emitter comprises issuing the spinning solution centrally and along the concave forward surface so as to distribute said spinning solution toward the forward surface discharge edge.
8. The process of claim 1 wherein the directing step comprises directing the spinning solution from the emitter toward the collector in a direction against gravity.
9. The process of claim 1 wherein the spinning solution has a viscosity of up to 1000 centipoise.
10. The process of claim 9 wherein the spinning solution has a viscosity of up to 100 centipoise.
11. The process of claim 1 wherein supplying the spinning solution to the emitter occurs at a throughput rate of 10-100 ml/min.
12. The process of claim 1 wherein the emitter and the collector are positioned to have a distance between them of 12-30 cm.
13. The process of claim 1 wherein air is supplied to the emitter at a rate of 3-12 scfm.
14. The process of claim 1 wherein the polymer is selected from the group of polyalkylene oxides, poly(meth)acrylates, polystyrene based polymers and copolymers, vinyl polymers and copolymers, fluoropolymers, polyesters and copolyesters, polyurethanes, polyalkylenes, polyamides, polyaramids, thermoplastic polymers, liquid crystal polymers, engineering polymers, biodegradable polymers, bio-based polymers, natural polymers, and protein polymers.
15. The process of claim 1 wherein the fibers have an average fiber diameter of up to 1,000 nm.
16. A fiber forming process comprising:
providing a centrifugal electrospinning apparatus comprising:
a rotating free surface edge emitter comprising:
a rotating element having a rotational speed of 10,000 rpm or less;
a discharge portion having a forward surface defining a concave shape including a perpendicular ring region;
a diffuser portion configured to mate with the discharge portion;
a controller; and
a voltage potential of 40-80 kV between the emitter and the collector;
providing a spinning solution having a viscosity of up to 1000 centipoise, the solution comprising at least one polymer dissolved in at least one solvent;
supplying the spinning solution to the emitter; and
directing the spinning solution from the emitter toward the collector under conditions effective to form separate fibrous streams from the spinning solution, vaporize the solvent, and product polymeric fibers on the collector.
17. The process of claim 16 wherein the rotating element of the emitter has a rotational speed of 3500 rpm or less.
18. The process of claim 16 wherein the spinning solution has a viscosity of up to 1000 centipoise.