System and method for formation of thin films with self-assembled monolayers embedded on their surfaces
The present invention relates to a method for the formation of virtually defect-free monolayers of particles with long-range order. The technique involves assembling the monolayer of particles on the interface between a solidifiable liquid and a fluid, which can be air or another liquid, ordering the particles using an electric field and then solidifying the former, e.g., by applying UV light. The monolayer becomes embedded on the surface of the solidified film. The monolayers can be coated onto the surface of materials to optimize their mechanical, thermal, electrical and optical properties.
1. A process for producing a film with a monolayer of particles, the particles being arranged in long range order and being embedded on a surface of the film, the process comprising the steps of:
placing the particles in a flat interface between a first fluid and a second fluid, the first fluid being a UV curable resin;
applying an ac or dc electric field in a direction normal to the flat interface to cause movement of the particles based on dipole-dipole electrostatic repulsion and an electrostatic force that is normal to the interface, thereby forming a monolayer of the particles on the flat interface with controlled lattice spacing;
switching off the applied electric field;
curing the UV curable resin with the electric field switched off so as to form a solidified resin film in the absence of an applied electric field, the monolayer of particles with lattice spacing embedded on a surface of the solidified resin film, and the lattice spacing of the particles not significantly changing as a result of said switching off before the resin film is solidified; and
removing the second fluid from the solidified resin film.
2. The process of claim 1 , wherein the second fluid is selected from air, silicone oil, or corn oil.
3. The process of claim 1 , wherein the particles are deagglomerated from one another before said applying of the electric field.
4. The process of claim 1 , wherein said curing of the UV curable resin is conducted by applying UV light.
5. The process of claim 1 , wherein the lattice spacing of the particles corresponds to a defect-free lattice structure of the particles.
6. The process of claim 1 , wherein said curing takes place in less than one second.
7. The process of claim 1 , wherein said particles are in a size range of from about 100 nm to about 100 μm.
8. The process of claim 1 , wherein the particles are formed of a material selected from the group consisting of glass, silica, polystyrene, steel, and salt crystals.
9. The process of claim 1 , wherein the applied electric field is approximately uniform.
10. The process of claim 1 , wherein the lattice spacing of the particles is controllable by adjusting intensity of the applied electric field.
11. A process for producing a film, the process comprising the steps of:
placing particles in a flat interface between a first fluid and a second fluid, the first fluid being a UV curable resin;
applying an ac or dc electric field in a direction normal to the flat interface to cause movement of the particles based on dipole-dipole electrostatic repulsion and an electrostatic force that is normal to the interface, thereby forming a monolayer of the particles on the flat interface with lattice spacing;
switching off the applied electric field;
curing the UV curable resin with the electric field switched off so as to form a solidified resin film in the absence an applied electric field, the monolayer of particles with lattice spacing embedded on a surface of the solidified resin film, and the lattice spacing of the particles not significantly changing as a result of said switching off before the resin film is solidified;
removing the second fluid from the solidified resin film; and
dissolving or removing the particles from the solidified resin film, whereby regular pores are created in the solidified resin film as a result of said dissolving or removing the particles from the solidified resin film.
12. The process of claim 11 , wherein the second fluid is selected from air, silicone oil, or corn oil.
13. The process of claim 11 , wherein the particles are deagglomerated from one another before said applying of the electric field.
14. The process of claim 11 , wherein said curing of the UV curable resin is conducted by applying UV light.
15. The process of claim 11 , wherein the lattice spacing of the particles corresponds to a defect-free lattice structure of the particles with long-range order.
16. The process of claim 11 , wherein said curing takes place in less than one second.
17. The process of claim 11 , wherein the particles are in a size range of from about 100 nm to about 100 μm.
18. The process of claim 11 , wherein said particles are formed of a material selected from the group consisting of glass, silica, polystyrene, steel, and salt crystals.
19. The process of claim 11 , wherein the applied electric field is approximately uniform.
20. The process of claim 11 , wherein the lattice spacing of the particles is controllable by adjusting intensity of the applied electric field.