Claims
- 1. A drying apparatus for drying a layer of polymer-solvent solution on a substrate comprising:
- at least one manifold for conducting a gas across the length of the drying apparatus;
- a plurality of heating elements positioned in the at least one manifold to adjust the temperature of the gas; and
- a plurality of nozzles attached to the at least one manifold to direct the gas onto the substrate, each nozzle forming a temperature zone within the drying apparatus having a higher temperature than a preceding zone in a travel direction of the substrate.
- 2. The drying apparatus of claim 1, wherein a plurality of temperature sensing elements are located within the at least one manifold and spaced between the heating elements to monitor temperature of the gas flowing through the at least one manifold.
- 3. The drying apparatus of claim 2, wherein a computer monitors the plurality of temperature sensing elements in order to adjust the plurality of heating elements.
- 4. The drying apparatus of claim 1, wherein the at least one manifold comprises a single manifold connected to a center section of each nozzle of the plurality of nozzles and supplies the gas to the center of each nozzle.
- 5. The drying apparatus of claim 1, wherein the at least one manifold comprises two manifolds and each manifold is attached to an end of each nozzle of the plurality of nozzles in order to supply gas to each end of each nozzle.
- 6. The drying apparatus of claim 1, wherein a first manifold, a first plurality of heating elements and a first plurality of nozzles supply gas to a top portion of the substrate and a second manifold, a second plurality of heating elements and a second plurality of nozzles supply gas to a bottom portion of the substrate.
- 7. The drying apparatus of claim 1, wherein gas is supplied at a first end of the at least one manifold and the plurality of heating elements are distributed between the first end of the manifold and a second end of the manifold.
- 8. The drying apparatus of claim 1, wherein gas is supplied to a central portion of the at least one manifold, the plurality of heating elements are distributed between the central portion and a first end of the manifold, and cooling elements are distributed between the central portion and a second end of the manifold.
- 9. The drying apparatus of claim 1, wherein cooling gas is controllably supplied to each of the plurality of nozzles, the cooling gas and gas heated by the plurality of heating elements is mixed in order to further control the temperature of the gas applied to the substrate.
- 10. The drying apparatus of claim 1, wherein the substrate remains in each of the temperature zones for a maximum of 10 seconds and a maximum substrate heating rate of 10.degree. F./second is applied to the substrate.
- 11. The drying apparatus of claim 1, wherein the substrate remains in each of the temperature zones for a maximum of 5 seconds and a maximum substrate heating rate of 5.degree. F./second is applied to the substrate.
- 12. The drying apparatus of claim 1, wherein the gas is at least one of air, nitrogen and solvent-free gas.
- 13. A method for drying a layer of polymer-solvent solution on a substrate comprising the steps of:
- supplying a gas to a plurality of different portions of the substrate moving in a travel direction, the gas forming a temperature zone;
- selectively heating the gas so that the temperature of each temperature zone increases substantially continuously along the travel direction of the substrate; and
- controlling the temperature of the gas within each temperature zone to avoid defect formation in the drying of the layer of polymer-solvent solution.
- 14. The method of claim 13, wherein the plurality of zones form a gradual and continuous temperature gradient which changes from a lower temperature to a temperature close to the boiling point of the polymer-solvent solution.
- 15. The method of claim 13, wherein the gas is at least one of air, nitrogen and solvent-free gas.
- 16. The method of claim 13, wherein the substrate remains in each temperature zone for a maximum of 10 seconds and a maximum substrate heating rate of 10.degree. F./second is applied to the substrate.
- 17. The method of claim 13, wherein the substrate remains in each temperature zone for a maximum of 5 seconds and a maximum substrate heating rate of 5.degree. F./second is applied to the substrate.
- 18. A method using a drying apparatus for drying a layer of polymer-solvent solution on a substrate comprising the steps of:
- conducting, with at least one manifold, a gas across the length of the drying apparatus;
- positioning a plurality of heating elements in the at least one manifold to adjust the temperature of the gas;
- directing, with a plurality of nozzles attached to the at least one manifold, the gas onto the substrate;
- supplying radiant heat to a plurality of different portions of the substrate moving in a travel direction, the radiant heat forming a temperature zone, each temperature zone having a higher temperature than a preceding temperature zone along the travel direction of the substrate; and
- controlling the temperature within each temperature zone to avoid defect formation in the drying of the thick layer of polymer-solvent solution.
- 19. The method of claim 18, wherein the plurality of zones form a gradual and continuous temperature gradient which changes from a lower temperature to a temperature close to the boiling point of the polymer-solvent solution.
- 20. The method of claim 18, wherein the substrate remains in each temperature zone for a maximum of 10 seconds and a maximum substrate heating rate of 10.degree. F./second is applied to the substrate.
- 21. The method of claim 18, wherein the substrate remains in each temperature zone for a maximum of 5 seconds and a maximum substrate heating rate of 5.degree. F./second is applied to the substrate.
ORIGIN OF THE INVENTION
This invention was made with government support under grant number ECD-8721551 awarded by the National Science Foundation. The government has certain rights in the invention.
US Referenced Citations (6)