Macroporous photonic crystal membrane, methods of making, and methods of use

1. A structure comprising:

a macroporous photonic crystal membrane including a three dimensional array of macropores, wherein a three dimensional polymer framework separates the macropores, wherein the polymer framework is made of a copolymer of two oligomers, wherein the two oligomers are ethoxylated (20) trimethylolpropane triacrylate (ETPTA 20) and polyethylene glycol (600) diacrylate (PEGDA 600), wherein when the macropores are in a collapsed state, the macroporous photonic crystal membrane is substantially transparent and wherein when the macropores are in an uncollapsed state, the macroporous photonic crystal membrane has an iridescent color.

2. The structure of claim 1 , wherein the three dimensional ordered array of macropores has a thickness of about 1 micron to 300 microns.

3. The structure of claim 1 , wherein macropores have a diameter of about 100 nm to 600 nm.

4. The structure of claim 1 , wherein the copolymer has a glass transition temperature of about −40° C. to −42° C.

5. The structure of claim 1 , wherein the macroporous photonic crystal membrane has the characteristic of when exposed to a liquid, the uncollapsed macropores transform to their collapsed state.

6. The structure of claim 1 , wherein the macroporous photonic crystal membrane has the characteristic of when the macropores are exposed to a vapor, the macropores transform into an uncollapsed state.

7. The structure of claim 6 , wherein the vapor is selected from the group consisting of: acetone, methanol, dichloromethane, benezene, toluene, and ethanol.

8. The structure of claim 6 , wherein the iridescent color is caused by Bragg diffraction of visible light and exposure to different gas vapors results in distinguishable and different Bragg diffraction of visible light.

9. The structure of claim 1 , wherein the macroporous photonic crystal membrane has the characteristic of when exposed to a liquid, the uncollapsed macropores transform to their collapsed state, wherein the macroporous photonic crystal membrane has the characteristic of when the macropores are exposed to a vapor, the macropores transform into an uncollapsed state.

10. A method of making a structure, comprising:

disposing nanoparticles onto a surface to form a three dimensional array of particles;

introducing a prepolymer mixture to the array of particles;

polymerizing the prepolymer mixture to form a polymer framework around the three dimensional array of particles; and

removing the particles to form a three dimensional array of macropores in a macroporous photonic crystal membrane, wherein the three dimensional polymer framework separates the macropores, wherein the polymer framework is made of a copolymer of two oligomers, wherein the two oligomers are ethoxylated (20) trimethylolpropane triacrylate (ETPTA 20) and polyethylene glycol (600) diacrylate (PEGDA 600), wherein when the macropores are in a collapsed state the macroporous photonic crystal membrane is substantially transparent, wherein when the macropores are in an uncollapsed state the macroporous photonic crystal membrane has an iridescent color.

11. The method of claim 10 , wherein the particles are silica particles.

12. The method of claim 10 , wherein removing includes dissolving the particles.

13. The method of claim 10 , further comprising: drying the macroporous photonic crystal membrane, wherein the macropores collapse so that the macroporous photonic crystal membrane is substantially transparent.

14. The method of claim 10 , wherein the copolymer has a glass transition temperature of about −40° C. to −42° C.