Nanocylinder arrays
Pathways to rapid and reliable fabrication of nanocylinder arrays are provided. Simple methods are described for the production of well-ordered arrays of nanopores, nanowires, and other materials. This is accomplished by orienting copolymer films and removing a component from the film to produce nanopores, that in turn, can be filled with materials to produce the arrays. The resulting arrays can be used to produce nanoscale media, devices, and systems.
1. A method of preparing an array of nanopores, the method comprising:
at least partially coating a conducting or semiconducting substrate with a copolymer comprising a first component and a second component;
mobilizing molecules in the copolymer for a time sufficient to allow the first component of the copolymer to form nanoscopic cylinders within the second component of the copolymer;
orienting the nanoscopic cylinders of the first component within the second component to form an oriented copolymer;
immobilizing molecules in the oriented copolymer; and
removing at least a portion of the first component from the oriented copolymer to form an array of nanopores in the copolymer.
2. The method of claim 1 , wherein the copolymer is a diblock copolymer.
3. The method of claim 1 , wherein the copolymer forms a film.
4. The method of claim 1 , wherein the nanoscopic cylinders are arranged in parallel and are vertically oriented with respect to the substrate.
5. The method of claim 1 , wherein mobilizing the molecules in the copolymer comprises heating the copolymer to a temperature above glass transition temperatures of both the first and second components, and immobilizing the molecules in the oriented copolymer comprises cooling the copolymer to below said glass transition temperatures.
6. The method of claim 5 , wherein the composite structure is heated for at least one hour.
7. The method of claim 1 , wherein mobilizing the molecules in the copolymer comprises adding a solvent, plasticizer, or a supercritical fluid to the copolymer, and immobilizing the molecules in the oriented copolymer comprises removing said solvent, plasticizer, or supercritical fluid.
8. The method of claim 1 , wherein orienting the nanoscopic cylinders comprises exposing the copolymer to an orienting force.
9. The method of claim 8 , wherein the copolymer is first exposed to an orienting force, has molecules mobilized, and then has molecules immobilized.
10. The method of claim 1 , wherein orienting the nanoscopic cylinders comprises
arranging a conducting layer on a surface of the copolymer to form a composite structure;
establishing an electric field through the copolymer;
heating the composite structure above the glass transition temperatures of both the first and second components for a time sufficient to allow the formation of nanoscopic cylinders; and
cooling the composite structure to a temperature below the glass transition temperature of both the first and second components.
11. The method of claim 8 , further comprising removing the electric field after cooling the composite structure.
12. The method of claim 8 , wherein the conducting layer comprises a conducting material and a further polymeric material.
13. The method of claim 10 , wherein the conducting material comprises metal, and the further polymeric material comprises a polyimide.
14. The method of claim 10 , wherein the heating is carried out before or during establishing the electric field.
15. The method of claim 10 , wherein the electric field has a value of from about 5 to about 10 V/μm.
16. The method of claim 1 , wherein an elastomeric material is applied to a surface of the copolymer to produce a smooth, oriented copolymer film surface.
17. The method of claim 1 , wherein mobilizing and orienting are conducted simultaneously.
18. The method of claim 1 , wherein removing of at least a portion of the first component from the oriented copolymer comprises selectively degrading the first component and not the second component.
19. The method of claim 1 , wherein removal of at least a portion of the first component comprises exposing the oriented copolymer to a degradation agent that selectively degrades the first component.
20. The method of claim 19 , wherein the degradation agent is radiation, a solvent, or a reactive oxygen compound.
21. The method of claim 20 , wherein the radiation is ultraviolet radiation or an electron beam.
22. The method of claim 20 , wherein the solvent is acetic acid.
23. The method of claim 1 , wherein the substrate comprises a metal.
24. The method of claim 1 , wherein the substrate comprises gold.
25. The method of claim 1 , wherein the copolymer is a block copolymer of methylmethacrylate as the first component and styrene as the second component.
26. The method of claim 1 , wherein at least a majority of the first component is removed.
27. The method of claim 1 , wherein the method further comprises at least partially filling the nanoscopic pores with a material.
28. The method of claim 27 , wherein the nanoscopic pores are at least partially filled by electrochemical deposition.
29. The method of claim 27 , wherein the nanoscopic pores are at least partially filled with a magnetic material.
30. The method of claim 29 , wherein the magnetic material comprises alternating layers of a magnetic metal and a non-magnetic material.
31. The method of claim 27 , wherein the nanoscopic pores and surface of the matrix are wetted with a surfactant prior to at least partially filling the nanopores with a material.
32. The method of claim 27 , wherein an electrical current is used to control the amount of material deposited in the pores.
33. An array of nanopores manufactured by the method of claim 1 .