MULTILAYER FILMS

• US 20100062232A1
• Filed: 12/14/2007
• Published: 03/11/2010
• Est. Priority Date: 12/15/2006
• Status: Abandoned Application

• Current Assignee: Drexel University
• Original Assignee: Drexel University
• Inventors: Cathell, Matthew D., Schauer, Caroline L., McIlwee, Holly A.
• Application Number:
  US12/296,197
• Publication Number:
  US 20100062232A1
• Time in Patent Office: Days
• US Class Current: 428/212
• CPC Class Codes: C08B 37/0072 Hyaluronic acid, i.e. HA or hyaluronan; Derivatives thereof, e.g. crosslinked hyaluronic acid (hylan) or hyaluronates
• CPC Class Codes: C08J 2305/00 Characterised by the use of polysaccharides or of their derivatives not provided for in groups C08J2301/00 or C08J2303/00
• CPC Class Codes: C08J 5/18 Manufacture of films or sheets
• CPC Class Codes: C09D 105/04 Alginic acid; Derivatives thereof
• CPC Class Codes: C09D 105/08 Chitin; Chondroitin sulfate; Hyaluronic acid; Derivatives thereof
• CPC Class Codes: G01N 21/78 producing a change of colour
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/31511 Of epoxy ether
• CPC Class Codes: Y10T 428/31678 Of metal
• CPC Class Codes: Y10T 428/31971 Of carbohydrate

Abstract

The present invention concerns multilayer films comprising a plurality of layers, at least some of the layers comprise (i) cross-linked chitosan, alginate, chondroitin sulfate, or hyaluronic acid and (ii) particles or void spaces; wherein the layers are 20-260 nm in thickness. Also disclosed are multilayer films comprising at least two of: a layer comprising a first polymer; a layer comprising a second polymer; a layer comprising particles, wherein said particles comprise ceramic material, metallic species, or both; and, a layer comprising a combination of said first polymer and said particles; wherein said multilayer film is capable of displaying structural color. Also provided are methods for making and using the inventive multilayer films and compositions comprising the multilayer films.

Claims

1. A multilayer film comprising a plurality of layers, wherein at least some of the layers comprise (i) cross-linked chitosan, alginate, chondroitin sulfate, or hyaluronic acid and (ii) particles or void spaces;

wherein the layers are 20-260 nm in thickness.

2. The film of claim 1, wherein at least some of the layers comprise chitosan.

3. The film of claim 1, wherein at least some of the layers comprise alginate.

4. The film of claim 1 comprising void spaces.

5. The film of claim 4, wherein the void spaces have a largest dimension less than the thickness of the layer in which the void resides.

6. The film of claim 5, wherein the void spaces have a largest dimension less than 50 nm.

7. The film of claim 1 comprising a plurality of particles.

8. The film of claim 7, wherein the particles have a largest dimension less than the thickness of the layer in which the particle resides.

9. The film of claim 8, wherein the particles have a largest dimension less than 50 nm.

10. The film of claim 7, wherein the particles comprise transition metals.

11. The film of claim 7, wherein the particles comprise gold, platinum, silver, or any

combination thereof.

12. The film of claim 7, wherein the particles are substantially spherical.

13. The film of claim 7, wherein the particles comprise one or more wires, each having a diameter less than the thickness of the layer.

14. The film of claim 1, wherein the film comprises at least one layer with a refractive index of 1.70 to 1.30.

15. The film of claim 14, wherein the film comprises at least two layers and where at least two layers differ in refractive index by at least 0.05.

16. A sensor for heavy metal ions comprising a film of claim 1.

17. The sensor of claim 16, wherein the film is adhered to an external surface of a substrate.

18. The sensor of claim 16 comprising chitosan, covalently modified chitosan, or alginate.

19. A method of producing a biopolymer film comprising:

providing a plurality of layers, at least some of the layers comprising cross-linked chitosan or alginate, said layers comprising a plurality of dispersed particles, the particles having a largest dimension less than the thickness of the layer; and

removing said particles from the layer, producing void spaces within said layer.

20. The method of claim 19 comprising chitosan.

21. The method of claim 19 comprising alginate.

22. The method of claim 19, wherein said dispersed particles are removed by dissolving the particles in a solvent and separating the solvent from the film.

23. The method of claim 19, wherein the particles comprise latex.

24. The method of claim 23, wherein the latex is carboxylic acid modified latex.

25. A method of producing a composition comprising:

forming a multilayer film comprising a plurality of layers, at least some of the layers comprise cross-linked chitosan or alginate and particles or void spaces;

wherein the layers are 20-260 nm in thickness,

converting the film to a series of pieces,

dissolving or dispersing the platelets into a liquid.

26. The method of claim 25, wherein the film comprises cross-linked chitosan.

27. The method of claim 26, wherein the film comprises cross-linked alginate.

28. The method of claim 26, wherein the film comprises void spaces.

29. The method of claim 28, wherein the void spaces are formed by providing a film comprising a plurality of layers having dispersed particles, the particles having a largest dimension less than the thickness of the layer;

and removing said particles from the layer, producing void spaces within said layer.

30. The method of claim 28, wherein the particles are latex.

31. The method of claim 28, wherein the void spaces are formed either before or after the film is converted to platelets.

32. A multilayer film comprising at least two of:

a layer comprising a first polymer;

a layer comprising a second polymer;

a layer comprising particles, wherein said particles comprise ceramic material, metallic species, or both; and

,

a layer comprising a combination of said first polymer and said particles;

wherein said multilayer film is capable of displaying structural color.

33. The multilayer film according to claim 32, wherein said first polymer is a biopolymer.

34. The multilayer film according to claim 33 wherein said first polymer is alginate, chitosan, chondroitin sulfate, hyaluronic acid, or any combination thereof.

35. The multilayer film according to claim 32 wherein said second polymer is poly(2,2,3,3,4,4,4-heptafluoromethacrylate-co-glycidyl methacrylate), poly(pentabromo-phenylmethacrylite-co-glycidyl-methacrylate), or polymerized titanium methacrylate triisopropoxide.

36. The multilayer film according to claim 32 comprising a layer comprising a first polymer and a layer comprising a second polymer, wherein said layer comprising a first polymer is adjacent to said layer comprising a second polymer without intervening layers, and wherein the refractive index of said second polymer is higher than the refractive index of said first polymer.

37. The multilayer film according to claim 32 wherein said metallic species comprises gold, silver, platinum, lead, palladium, lead acetate, zinc chloride, copper (II) sulfide pentahydrate, chromium (III) chloride, alumina, or any combination thereof.

38. The multilayer film according to claim 32 wherein said ceramic material comprises an oxide, a non-oxide, a composite, or any combination thererof.

39. The multilayer film according to claim 32 comprising a layer comprising a first polymer, a layer comprising a metallic species or a ceramic material, and a second layer comprising a first polymer, wherein said layer comprising a metallic species or a ceramic material or both is interposed between said layer comprising a first polymer and said second layer comprising a first polymer.

40. The multilayer film according to claim 32 comprising a layer comprising a first polymer, wherein said layer further comprises void spaces, and wherein said void spaces have a largest dimension less than the thickness of said layer.

41. The multilayer film according to claim 32 wherein said layers are about 20 nm to about 1.2 μ

m in thickness.