Reversible actuation in arrays of nanostructures

1. An apparatus, comprising:

a substrate with a surface;

a polymer layer attached to a region of the surface;

a plurality of nanostructures, a first end of each nanostructure being in the polymer layer and a second end of each nanostructure protruding from the polymer layer;

wherein the nanostructures are configured to move in a predetermined direction from a first position to a second position in response to a change in thickness of the polymer layer from a first thickness thereof to a second thickness.

2. The apparatus as recited in claim 1 wherein the nanostructures are configured to tilt with respect to a normal of the surface in response to the change in thickness.

3. The apparatus as recited in claim 1 wherein the plurality of nanostructures are an array of nanoposts.

4. The apparatus as recited in claim 1 wherein the plurality of nanostructures are a plurality of nanoplates.

5. The apparatus as recited in claim 1 wherein the polymer layer is a hydrogel layer.

6. The apparatus as recited in claim 1 wherein the first end of each nanostructure is in direct contact with the surface.

7. The apparatus as recited in claim 1 wherein the first end of each nanostructure is separated from the surface.

8. The apparatus as recited in claim 1 wherein the nanostructures are configured to substantially return to the first position as the polymer layer returns toward the first thickness.

9. The apparatus as recited in claim 1 wherein the substrate has surface topological therein configured to cause the plurality of nanostructures to move in the predetermined direction.

10. The apparatus as recited in claim 1 wherein the thickness of the polymer layer is controlled using a stimulus selected from the group of:

moisture change;

temperature change;

magnetic field change;

electrical field change;

pH change; and

ion concentration change.

11. A method for using an apparatus, comprising:

providing an apparatus, the apparatus including;

a substrate with a surface;

a polymer layer attached to a region of the surface; and

a plurality of nanostructures, a first end of each nanostructure being in the polymer layer and a second end of each nano structure protruding through the polymer layer; and

exposing the polymer layer to a stimulus, the stimulus changing a thickness of the polymer layer from a first thickness to a second thickness and thereby moving the nano structures in a predetermined direction from a first position to a second position.

12. The method as recited in claim 11 wherein exposing the polymer layer to a stimulus thereby tilts the nanostructures with respect to a normal of the surface.

13. The method as recited in claim 11 , further including causing the thickness of the polymer layer to return to the first thickness, thereby substantially returning the nanostructures to the first position.

14. The method as recited in claim 11 wherein exposing the polymer layer to a stimulus includes exposing the polymer layer to a stimulus selected from the group consisting of:

moisture change;

temperature change;

magnetic field change;

electrical filed change pH change; and

ion concentration change.

15. The method as recited in claim 11 wherein exposing the polymer layer closes one or more micro fluidic channels, tunable photonic structures or micromanipulators.

16. A method for manufacturing an apparatus, comprising:

providing a substrate with a surface;

forming a plurality of nanostructures, a first end of each nanostructure being in a polymer layer attached to a region of the surface and a second end of each nanostructure protruding through the polymer layer;

wherein the nanostructures are configured to move in a predetermined direction from a first position to a second position in response to a change in the thickness of the polymer layer from a first thickness to a second thickness.

17. The method as recited in claim 16 wherein the polymer layer is a hydrogel layer.

18. The method as recited in claim 16 wherein the first end of each nanostructure is in direct contact with the surface.

19. The method as recited in claim 16 wherein the first end of each nanostructure is separated from the surface.

20. The method as recited in claim 16 wherein providing a substrate with a surface includes providing a substrate with a surface having topography therein, the topography configured to cause the plurality of nanostructures to move in the predetermined direction.