Scanned source oriented nanofiber formation
Nanofibers are formed using electrospray deposition from microfluidic source. The source is brought close to a surface, and scanned in one embodiment to form oriented or patterned fibers. In one embodiment, the surface has features, such as trenches on a silicon wafer. In further embodiments, the surface is rotated to form patterned nanofibers, such as polymer nanofibers. The nanofibers may be used as a mask to create features, and as a sacrificial layer to create nanochannels.
1. A method of forming nanofibers, the method comprising:
positioning a target substrate and counter electrode a desired distance from a microfluidic emitter having an emitter tip;
providing a polymer to the microfluidic emitter tip;
applying a potential between the microfluidic emitter tip and the target substrate to create nanofibers on the target substrate and;
creating lateral movement between the target substrate and the microfluidic emitter.
2. The method of claim 1 and further comprising using an x-y motion stage to provide lateral movement.
3. The method of claim 1 wherein the lateral movement is provided by rotating the target substrate to obtain a surface velocity of up to approximately 168 cm/s with respect to the microfluidic emitter tip.
4. The method of claim 1 wherein the lateral movement is provided by rotating the target substrate between 40 and 800 RPM.
5. The method of claim 1 wherein the desired distance is between approximately 0.5 cm to 2.0 cm flow of the polymer.
6. The method of claim 1 wherein the applied potential is between 2000 V and 8500 V.
7. The method of claim 1 wherein the polymer is provided to the tip by dipping the tip in the polymer.
8. The method of claim 1 wherein the polymer is provided to the tip by an applicator.
9. The method of claim 1 wherein the polymer comprises a colloidal suspension.
10. The method of claim 1 wherein the nanofibers are less than 100 nm in diameter.
11. A method of forming nanofibers, the method comprising:
positioning a target substrate and counter electrode a desired distance from a microfluidic emitter having an emitter tip;
providing a polymer to the microfluidic emitter tip; and
applying a potential between the microfluidic emitter tip and the target substrate to create nanofibers on the target substrate, wherein the polymer comprises a colloidal suspension including nanospheres.
12. A method of forming nanofibers, the method comprising:
forming features on a target substrate;
positioning the target substrate and metal counter electrode a desired distance from a microfluidic emitter;
providing a polymer to the microfluidic emitter; and
applying a potential between the microfluidic emitter and the target substrate to create nanofibers spanning the features on the target substrate.
13. The method of claim 12 wherein the feature comprises a trench.
14. The method of claim 13 wherein the trench is between approximately 3 um to 5 um in width, and approximately 2 um in depth.
15. The method of claim 12 and further comprising providing lateral movement of the target substrate relative to the microfluidic emitter.
16. A method of forming nanofibers, the method comprising:
positioning a target substrate and aluminum counter electrode a desired distance of between 0.5 and 2.0 cm from a microfluidic emitter tip;
rotating the target substrate with respect to the microfluidic emitter tip;
pumping a polymer through the microfluidic emitter; and
applying a potential of between 2000 V and 8500 V between the microfluidic emitter tip and the target substrate to create nanofibers that are approximately 100 nm in diameter on the target substrate.
17. The method of claim 16 wherein the target substrate is rotated to obtain a surface velocity with respect to the microfluidic emitter that results in substantially straight nanofibers being formed on the target substrate.
18. A method of forming nanofibers, the method comprising:
positioning a target substrate a desired distance from a source;
pumping a polymer through the source; and
moving the source to create nanofibers having a desired orientation on the target substrate.