Self-assembly of block copolymers on topographically patterned polymeric substrates

1. A method of forming a nanopatterned surface, comprising:

forming a polymeric replica of a topographically patterned crystalline surface; wherein the polymeric replica comprises a topographically patterned surface opposing the topographically patterned crystalline surface;

forming a block copolymer film on the topographically patterned surface of the polymeric replica; and

annealing the block copolymer film to form an annealed block copolymer film comprising a nanopatterned surface.

2. The method of claim 1 , wherein the annealed block copolymer film comprises a hexagonal array of cylindrical microdomains.

3. The method of claim 2 , wherein the hexagonal array of cylindrical microdomains exhibits an orientation order of at least 0.9 over an area of at least 1 centimeter 2 .

4. The method of claim 2 , wherein the hexagonal array of cylindrical microdomains exhibits an orientation order greater than that of the polymeric replica.

5. The method of claim 2 , wherein the cylindrical microdomains are separated by a nearest-neighbor distance of about 10 to about 100 nanometers.

6. The method of claim 2 , wherein the forming a polymeric replica comprises contacting a polymer film comprising a polymer having a glass transition temperature, T g , with the topographically patterned crystalline surface at a temperature greater than T g .

7. The method of claim 6 , wherein the polymer has a melting temperature, T m , and wherein the contacting the polymer film with the topographically patterned crystalline surface is conducted at a temperature less than T m .

8. The method of claim 1 , wherein the patterned surface of the polymeric replica comprises a sawtooth pattern characterized by a peak-to-peak separation, L R ; wherein the block copolymer film comprises a hexagonal array of cylindrical microdomains characterized by a nearest-neighbor micro domain separation, L BCP ; and wherein L R /L BCP has a value of about 1 to about 10.

9. The method of claim 1 , wherein the forming a polymeric replica comprises polymerizing a monomer composition in contact with the topographically patterned crystalline surface.

10. The method of claim 1 , wherein the forming a polymeric replica comprises reacting a first polymer in contact with the topographically patterned crystalline surface to form a second polymer in contact with the topographically patterned crystalline surface.

11. The method of claim 1 , wherein the polymeric replica comprises a polymer selected from the group consisting of polydimethylsiloxanes, poly(butylene terephthalate)s, random copolymers of tetrafluoroethylene and hexafluoropropylene, and polyimides derived from pyromellitic dianhydride and 4,4′-oxydianiline.

12. The method of claim 1 , wherein the polymeric replica comprises a polymer having a flexural modulus of about 100 to about 10,000 megapascals measured at 23° C. according to ASTM D790-03, Procedure A.

13. The method of claim 1 , wherein the topographically patterned surface comprises a sawtooth pattern characterized by a peak-to-peak separation of about 24 to about 200 nanometers and a peak-to-valley separation of about 3 to about 20 nanometers.

14. The method of claim 1 , wherein the topographically patterned surface comprises a grooved pattern characterized by a groove depth of about 3 to about 20 nanometers and a groove-to-groove separation of about 24 to about 200 nanometers.

15. The method of claim 1 , wherein the topographically patterned crystalline surface is an annealed surface of a single crystal aluminum oxide substrate.

16. The method of claim 1 , wherein the topographically patterned crystalline surface is a substantially planar surface of a single crystal substrate; wherein the substantially planar surface is at least one degree removed from any crystallographic plane of the single crystal substrate.

17. The method of claim 1 , wherein the block copolymer film comprises a block copolymer selected from the group consisting of polystyrene-b-poly(4-vinylpyridine)s, polystyrene-b-poly(2-vinylpyridine)s, and polystyrene-b-poly(ethylene oxide)s.

18. The method of claim 1 ,

wherein the block copolymer film comprises a polystyrene-b-poly(ethylene oxide);

wherein the polystyrene-b-poly(ethylene oxide) comprises a polystyrene block having a number average molecular weight of about 6,000 to about 30,000 atomic mass units and a poly(ethylene oxide) block having a number average molecular weight of about 2,000 to about 10,000 atomic mass units; and

wherein a ratio of the number average molecular weight of the polystyrene block to the number average molecular weight of the poly(ethylene oxide) block is about 2:1 to about 6:1.

19. The method of claim 1 , wherein the block copolymer film has a thickness of about 10 to about 100 nanometers.

20. The method of claim 1 , wherein the block copolymer film comprises a polystyrene-b-poly(ethylene oxide); and wherein the annealing the block copolymer film comprises exposing the block copolymer film to an annealing solvent vapor comprising o-xylene.

21. The method of claim 1 , further comprising surface reconstructing the annealed block copolymer film.

22. The method of claim 1 ,

wherein the forming a polymeric replica comprises contacting a surface of a poly(butylene terephthalate) film with an annealed surface of a single crystal aluminum oxide substrate, wherein the contacting is conducted at a temperature of about 180 to about 210° C.;

wherein the annealed surface of the single crystal aluminum oxide comprises a sawtooth pattern characterized by a peak-to-peak separation of about 70 to about 200 nanometers and a peak-to-valley separation of about 5 to about 20 nanometers;

wherein the forming a block copolymer film comprises forming a polystyrene-b-poly(ethylene oxide) film on the topographically patterned surface of the poly(butylene terephthalate) replica;

wherein the polystyrene-poly(ethylene oxide) diblock copolymer film has a thickness of about 10 to about 50 micrometers;

wherein the annealing the block copolymer film comprises annealing the polystyrene-b-poly(ethylene oxide) film in o-xylene vapor; and

wherein the annealed block copolymer film comprises a hexagonal array of cylindrical poly(ethylene oxide) microdomains.

23. A method of forming a nanopatterned surface, comprising:

forming a block copolymer film on a topographically patterned surface of a polymer layer; wherein the topographically patterned surface of the polymer layer is formed in contact with a topographically patterned crystalline surface; and

annealing the block copolymer film to form an annealed block copolymer film comprising a nanopatterned surface.