Scanned source oriented nanofiber formation

• US 7,537,807 B2
• Filed: 09/27/2004
• Issued: 05/26/2009
• Est. Priority Date: 09/26/2003
• Status: Expired due to Fees

• Current Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Original Assignee: Cornell University
• Inventors: Kameoka, Jun, Craighead, Harold G.
• Primary Examiner(s): Parker; Frederick J
• Application Number:
  US10/951,254
• Publication Number:
  US 20050123688A1
• Time in Patent Office: 1,702 Days
• Field of Search: None
• US Class Current: 427/458
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C23F 17/00 Multi-step processes for surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by subclass C21D or C22F or class C25 coating for obtaining at least two superposed coatings either by methods not provided for in a single one of main groups C23C2/00 - C23C26/00, or by combinations of methods providedfor in subclasses C23C and C25D, C23C28/00
• CPC Class Codes: D01D 5/0069 characterised by the spinning section, e.g. capillary tube, protrusion or pin
• CPC Class Codes: D01F 6/64 from polycarbonates
• CPC Class Codes: D01F 6/66 from polyethers
• CPC Class Codes: Y10S 977/856 including etching/cutting
• CPC Class Codes: Y10S 977/888 Shaping or removal of materials, e.g. etching
• CPC Class Codes: Y10T 428/24562 Interlaminar spaces

Abstract

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.

Claims

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.