Magnetic composites exhibiting distinct flux properties due to gradient interfaces

• US 6,322,676 B1
• Filed: 03/25/1998
• Issued: 11/27/2001
• Est. Priority Date: 03/25/1998
• Status: Expired due to Fees

• Current Assignee: University of Iowa Research Foundation
• Original Assignee: University of Iowa Research Foundation
• Inventors: Leddy, Johna, Amarasinghe, Sudath
• Primary Examiner(s): Tung, T.
• Application Number:
  US09/047,494
• Time in Patent Office: 1,343 Days
• Field of Search: 204/295, 204/296, 204/280, 204/290 R, 204/291-293, 204/400, 204/416-419, 204/DIG. 5, 428/692, 428/693, 428/694 MM, 428/900, 428/928, 429/12, 429/212, 365/158
• US Class Current: 204/296
• CPC Class Codes: B01D 39/04 Organic material, e.g. cellulose, cotton
• CPC Class Codes: B01D 39/06 Inorganic material, e.g. asbestos fibres, glass beads or fibres
• CPC Class Codes: B03C 1/01 by addition of magnetic adjuvants
• CPC Class Codes: B03C 1/02 acting directly on the substance being separated
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: C23C 30/00 Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process C23C26/00, C23C28/00 take precedence
• CPC Class Codes: C25B 11/00 Electrodes; Manufacture thereof not otherwise provided for
• CPC Class Codes: H01M 4/86 Inert electrodes with catalytic activity, e.g. for fuel cells
• CPC Class Codes: H01M 4/8605 Porous electrodes
• CPC Class Codes: H01M 8/00 Fuel cells; Manufacture thereof
• CPC Class Codes: H01M 8/1004 characterised by membrane-electrode assemblies [MEA] H01M8/12 takes precedence
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y10S 204/05 Magnetic plus electrolytic
• CPC Class Codes: Y10S 428/90 Magnetic feature
• CPC Class Codes: Y10T 428/32 Composite [nonstructural laminate] of inorganic material having metal-compound-containing layer and having defined magnetic layer

Abstract

Magnetic composites exhibit distinct flux properties due to gradient interfaces. The composites can be used to improve fuel cells and effect transport and separation of different species of materials. A variety of devices can be made utilizing the composites including a separator, a cell, an electrode for channeling flux of magnetic species, an electrode for effecting electrolysis of magnetic species, a system for channeling electrolyte species, a system for separating particles with different magnetic susceptibilities. Some composites can be used to make a dual sensor for distinguishing between two species of materials and a flux switch to regulate the flow of a redox species and a flux switch to regulate the flow of a chemical species. Some composites can control chemical species transport and distribution.

Claims

1. A separator for separating a first type of particle having a first magnetic susceptibility from a second type of particle having a second magnetic susceptibility, comprising:

a first material having a first magnetism, said first material comprising magnetic microbeads;

a second material having a second magnetism, said second material comprising an ion exchange polymer, said second material forming a microstructured composite with said first material; and

a plurality of boundaries between said first material and said second material, said plurality of boundaries providing a plurality of paths between a first region and a second region, each of said plurality of boundaries having a magnetic gradient within said plurality of paths;

said magnetic gradient causing said first type of particle to pass through said second material at a greater rate than said second type of particle.

2. The separator as claimed in claim 1, further comprising an electrode, said electrode located within said second region.

3. The separator as claimed in claim 1, wherein said first material having a first magnetism comprises paramagnetic microbeads.

4. The separator as claimed in claim 3, wherein said super-paramagnetic microbeads have magnetic spins reversibly changeable between aligned when an externally applied magnetic field is turned on and disordered when said externally applied magnetic field is turned off.

5. The separator as claimed in claim 1, wherein said first material having a first magnetism comprises microbeads comprising at least one of Fe and Fe oxide.

6. The separator as claimed in claim 1, wherein said first material having a first magnetism comprises diamagnetic material reversibly changeable to paramagnetic material.

7. The separator as claimed in claim 1, wherein said first material having a first magnetism comprises diamagnetic material reversibly changeable to paramagnetic material in the presence of an externally applied magnetic field.

8. The separator as claimed in claim 1, wherein said first material having a first magnetism comprises polymer coated microbeads comprising organo-Fe.

9. The separator as claimed in claim 1, wherein said first material having a first magnetism comprises polymer coated microbeads comprising at least one of Fe and Fe oxide.

10. The separator as claimed in claim 1, wherein said first material having a first magnetism comprises diamagnetic microbeads reversibly changeable to paramagnetic microbeads.

11. The separator as claimed in claim 1, wherein said first material having a first magnetism comprises diamagnetic microbeads reversibly changeable to paramagnetic microbeads in the presence of an externally applied magnetic field.

12. The separator as claimed in claim 1, wherein said first material having a first magnetism comprises polymer coated diamagnetic microbeads reversibly changeable to polymer coated paramagnetic microbeads.

13. The separator as claimed in claim 1, wherein said first material having a first magnetism comprises polymer coated diamagnetic microbeads reversibly changeable to polymer coated paramagnetic microbeads in the presence of an externally applied magnetic field.

14. The separator as claimed in claim 1, wherein said second material having a second magnetism comprises perfluorinated sulfonic acid, and said first material having a first magnetism comprises polymer coated magnetic microbeads.

15. The separator as claimed in claim 1, wherein said first material having a first magnetism comprises uncoated magnetic microbeads.

16. The separator as claimed in claim 1, further comprising an external magnetic field turned on or off, and wherein said second material having a second magnetism comprises perfluorinated sulfonic acid, and said first material having a first magnetism comprises polystyrene coated Fe/Fe oxide microbeads.

17. The separator as claimed in claim 1, wherein said second material having a second magnetism comprises perfluorinated sulfonic acid, and said first material having a first magnetism comprises polystyrene coated organo-Fe microbeads.

18. The separator as claimed in claim 1, wherein said first material comprises a paramagnetic species and wherein said second material comprises a diamagnetic species.

19. The separator as claimed in claim 1, wherein said first material comprises a paramagnetic species having a first magnetic susceptibility and said second material comprises a different paramagnetic species having a second magnetic susceptibility.

20. The separator as claimed in claim 1, wherein said first material comprises a diamagnetic species having a first magnetic susceptibility and said second material comprises a different diamagnetic species having a second magnetic susceptibility, and said first magnetic susceptibility is different from said second susceptibility.

21. The separator as claimed in claim 1, wherein said first material comprises a paramagnetic species having a first magnetic susceptibility and said second material comprises a nonmagnetic species.

22. The separator as claimed in claim 1, wherein said first material comprises a diamagnetic species having a first magnetic susceptibility and said second material comprises a nonmagnetic species.

23. The separator as claimed in claim 1, wherein the first and second materials each further comprise a solid and a gas.

24. The separator as claimed in claim 1, wherein said plurality of paths have an average width in the range of from about 1 nanometer to about 10 micrometers.

25. The separator as claimed in claim 1, wherein said plurality of paths have an average width in the range of from about 1 nanometer to about 2 micrometers.

26. The separator as claimed in claim 1, wherein said plurality of paths have an average width in the range of from about 1 nanometer to about 0.5 micrometer.

27. The separator as claimed in claim 1, wherein said microstructured composite comprises said plurality of paths.

28. The separator as claimed in claim 27, wherein said microstructured composite comprises a coating on a subtrate.

29. The separator as claimed in claim 28, wherein said substrate comprises an electrode.

30. The separator as claimed in claim 1, wherein said microstructured composite comprises a coating on a substrate.

31. A cell, comprising:

an electrolyte including a first type of particles;

said first type of particles having a first magnetic susceptibility;

a first electrode arranged in said electrolyte; and

a second electrode arranged in said electrolyte, wherein said first type of particles transform into a second type of particles once said first type of particles reach said second electrode, said second type of particles having a second magnetic susceptibility, wherein said first and said second magnetic susceptibilities are different, said second electrode having a surface with a coating which includes;

a first material having a first magnetism, said first material comprising magnetic microbeads;

a second material having a second magnetism, said second material comprising magnetic an ion exchange polymer; and

a plurality of boundaries providing a plurality of paths between said electrolyte and said surface of said second electrode, each of said plurality of boundaries providing a magnetic gradient within each of said plurality of paths.

32. The cell as claimed in claim 31, wherein said first material comprises a paramagnetic species and wherein said second material comprises a diamagnetic species.

33. The cell as claimed in claim 31, wherein said first material comprises a paramagnetic species having a first magnetic susceptibility and said second material comprises a paramagnetic species having a second magnetic susceptibility, and said first magnetic susceptibility is different from said second susceptibility.

34. The cell as claimed in claim 31, wherein said first material comprises a diamagnetic species having a first magnetic susceptibility and said second material comprises a diamagnetic species having a second magnetic susceptibility, and said first magnetic susceptibility is different from said second susceptibility.

35. The cell as claimed in claim 31, wherein said first material comprises a paramagnetic species having a first magnetic susceptibility and said second material comprises a nonmagnetic species.

36. The cell as claimed in claim 31, wherein said first material comprises a diamagnetic species having a first magnetic susceptibility and said second material comprises a nonmagnetic species.

37. The cell as claimed in claim 31, wherein said electrolyte comprises an electrolyzable gas.

38. The cell as claimed in claim 31, wherein said electrolyte comprises O₂.

39. The cell as claimed in claim 31, wherein said electrolyte comprises a chlor-alkali.

40. The cell as claimed in claim 31, wherein the coating on the surface of said second electrode comprises a magnetic composite.

41. The cell according to claim 31, wherein said plurality of paths have an average width in the range of from approximately one nanometer to approximately three micrometers.

42. An electrode for channeling flux of magnetic species, comprising:

a conductor; and

a composite in surface contact with said conductor, said composite including a first material having a first magnetism and a second material having a second magnetism, wherein said first material comprises magnetic microbeads and said second material comprises an ion exchange polymer, said composite having a plurality of boundaries providing pathways between said first material and said second material, wherein said pathways channel the flux of said magnetic species through said pathways to said conductor.

43. The electrode as claimed in claim 42, wherein said first material comprises a paramagnetic material having a first magnetic susceptibility and said second material comprises a paramagnetic material having a second magnetic susceptibility.

44. An electrode for effecting electrolysis of magnetic species, comprising:

a conductor; and

magnetic means in surface contact with said conductor for enhancing the flux of said magnetic species in an electrolyte solution to said conductor and effecting electrolysis of said magnetic species, wherein said magnetic means comprises a magnetic composite, said magnetic composite comprising magnetic microbeads and an ion exchange polymer.

45. An electrode for effecting electrolysis of magnetic species, comprising:

a conductor; and

means in surface contact with said conductor for enhancing the flux of said magnetic species to said conductor and effecting electrolysis of said magnetic species, wherein said means in surface contact with said conductor is a composite material, said composite material comprising magnetic microbeads and an ion exchange polymer.

46. An electrode for electrolysis of magnetic species, comprising:

a conductor; and

a composite magnetic material in surface contact with said conductor, said composite magnetic material comprising magnetic microbeads and an ion exchange polymer, said composite having a plurality of transport pathways through said composite magnetic material, said plurality of transport pathways enhancing the passage of said magnetic species to said conductor and effecting electrolysis of said magnetic species.

47. The electrode as claimed in claim 46, wherein said plurality of transport pathways have magnetic gradients which enhance the passage of said magnetic species to said conductor.

48. An improved fuel cell having two electrodes and a flux of O₂ between said two electrodes, wherein one of said two electrodes is the electrode claimed in claim 46, said composite magnetic material thereby enhancing flux of O₂ to said one electrode.

49. A system, comprising:

a first electrolyte species having a first magnetic susceptibility;

a second electrolyte species having a second magnetic susceptibility; and

means for preferentially channeling, from a first region to a second region, said first electrolyte species having a first magnetic susceptibility, as compared with said second electrolyte species having a second magnetic susceptibility, wherein said means for preferentially channeling comprises a first material having a first magnetism forming a microstructured composite with a second material having a second magnetism, said second material comprising an ion exchange polymer;

wherein said microstructured composite contains magnetic gradients that cause said first electrolyte species to pass through said second material at a greater rate than said second electrolyte species.

50. The system as claimed in claim 49, wherein said first material comprises a paramagnetic species and wherein said second material comprises a diamagnetic species.

51. The system as claimed in claim 49, wherein said first material comprises a diamagnetic species having a first magnetic susceptibility and said second material comprises a different diamagnetic species having a second magnetism.

52. The system as claimed in claim 49, wherein said first material comprises a paramagnetic species having a first magnetism and said second material comprises a nonmagnetic species.

53. The system as claimed in claim 49, wherein said first material comprises a diamagnetic species having a first magnetism and said second material comprises a nonmagnetic species.

54. A system for separating first particles and second particles having respective different first and second magnetic susceptibilities, comprising:

a first material having a first magnetism; and

a second material having a second magnetism, said second material comprising an ion exchange polymer and forming a microstructured composite with said first material, said second material working in conjunction with said first material to produce magnetic gradients, said magnetic gradients causing said first particles to pass through said second material at a greater rate than said second particles.

55. A composite material for controlling chemical species transport, comprising:

an ion exchanger; and

a graded density layer, wherein said ion exchanger is sorbed into said graded density layer.

56. The composite material as claimed in claim 55, wherein said composite material has a first side in closer proximity to the source of said chemical species and a second side more distal than said first side to said source of said chemical species, and wherein said graded density layer has a density gradient substantially pointing in the direction from said first side towards said second side.

57. The composite material as claimed in claim 55, wherein said composite material has a first side in closer proximity to the source of said chemical species and a second side more distal than said first side to said source of said chemical species, and wherein said graded density layer has a density gradient substantially pointing in the direction from said second side towards said first side.

58. A magnetic composite material for controlling transport of magnetic chemical species according to their magnetic susceptibility, comprising:

an ion exchanger;

a polymer coated magnetic microbead material; and

a graded density layer, wherein said ion exchanger and said polymer coated magnetic microbead material are sorbed into said graded density layer.

59. A composite material for controlling chemical species viscous transport, comprising:

an ion exchanger; and

a graded viscosity layer, wherein said ion exchanger is sorbed into said graded viscosity layer.

60. A magnetic composite material for controlling magnetic chemical species transport and distribution, comprising:

an ion exchanger;

a polymer coated magnetic microbead material; and

a graded density layer, wherein said ion exchanger and said polymer coated magnetic microbead material are sorbed into said graded density layer forming a gradient in the density of said polymer coated magnetic microbead material substantially perpendicular to a density gradient in said graded density layer.

61. A magnetic composite material for controlling magnetic chemical species transport and distribution, comprising:

an ion exchanger;

a polymer coated magnetic microbead material; and

a graded density layer, wherein said ion exchanger and said polymer coated magnetic microbead material are sorbed into said graded density layer forming a gradient in the density of said polymer coated magnetic microbead material substantially parallel to a density gradient in said graded density layer.

62. An ion exchange composite for controlling chemical species transport from a source of the chemical species, comprising:

an ion exchanger; and

a laminate graded density layer having a first side and a second side, wherein said ion exchanger is one of sorbed into said graded density layer and cocast on said graded density layer, and said graded density layer and said ion exchanger are contained within said first side and said second side, wherein said first side is in closer proximity to said source of said chemical species and said second side is more distal to said source of said chemical species, and wherein said laminate graded density layer has lower density toward said first side and higher density toward said second side, substantially increasing in density in a direction from said first side toward said second side.

63. The ion exchange composite as claimed in claim 62, further comprising a polymer coated magnetic microbead material sorbed into said laminate graded density layer.

64. The ion exchange composite as claimed in claim 63, wherein said laminate graded density layer comprises a gradient in the density of said polymer coated magnetic microbead material in a direction substantially perpendicular to the direction from said first side toward said second side.

65. The ion exchange composite as claimed in claim 63, wherein said laminate graded density layer comprises a gradient in the density of said polymer coated magnetic microbead material in a direction substantially parallel to the direction from said first side toward said second side.

66. An ion exchange composite for controlling chemical species transport from a source of the chemical species, comprising:

an ion exchanger; and

a laminate graded density layer having a first side and a second side, wherein said ion exchanger is one of sorbed into said graded density layer and cocast on said graded density layer, and said ion exchanger and said laminate graded density layer are contained within said first side and said second side, wherein said first side is in closer proximity to said source of said chemical species and said second side is more distal to said source of said chemical species, and wherein said laminate graded density layer has higher density toward said first side and lower density toward said second side, substantially decreasing in density in a direction from said first side toward said second side.

67. The ion exchange composite as claimed in claim 66, further comprising a polymer coated magnetic microbead material sorbed into said laminate graded density layer.

68. The ion exchange composite as claimed in claim 67, wherein said laminate graded density layer comprises a gradient in the density of said polymer coated magnetic microbead material in a direction substantially perpendicular to the direction from said first side toward said second side.

69. The ion exchange composite as claimed in claim 67, wherein said laminate graded density layer comprises a gradient in the density of said polymer coated magnetic microbead material in a direction substantially parallel to the direction from said first side toward said second side.

70. A flux switch to regulate the flow of a redox species, comprising:

an electrode;

a coating on said electrode, wherein said coating is formed from a composite comprising;

a magnetic microbead material having an aligned surface magnetic field;

an ion exchange polymer; and

an electro-active polymer in which a first redox form is paramagnetic and a second redox form is diamagnetic, wherein said flux switch is actuated by electrolyzing said electro-active polymer from said first redox form ordered in said magnetic field to said second redox form disordered in said magnetic field.

71. The flux switch as claimed in claim 70, wherein said magnetic microbead material further comprises organo-Fe material.

72. The flux switch as claimed in claim 70, wherein said redox species is more readily electrolyzed than said electro-active polymer.

73. The flux switch as claimed in claim 70, wherein said electro-active polymer comprises an electro-active liquid crystal with chemical properties susceptible to said magnetic field.

74. The flux switch as claimed in claim 70, wherein said electro-active polymer comprises an electro-active liquid crystal with viscosity susceptible to said magnetic field.

75. The flux switch as claimed in claim 70, wherein said electro-active polymer comprises an electro-active liquid crystal with phase susceptible to said magnetic field.

76. The flux switch as claimed in claim 70, wherein said electro-active polymer comprises poly(vinyl ferrocenium).

77. The flux switch as claimed in claim 70, further comprising an externally applied magnetic field, and wherein said magnetic microbead material comprises organo-Fe material.

78. A flux switch to regulate the flow of a chemical species, comprising:

an electrode; and

a coating on said electrode, wherein said coating is formed from a composite comprising;

a non-permanent magnetic microbead material;

an ion exchange polymer; and

a polymer with magnetic material that is convertible between a paramagnetic form and a diamagnetic form, and wherein said flux switch is actuated by reversibly converting said magnetic material from said paramagnetic form to said diamagnetic form by turning an externally applied magnetic field on or off.

79. The flux switch as claimed in claim 78, wherein said polymer with magnetic material contained therein has chemical properties susceptible to an externally applied magnetic field.

80. The flux switch as claimed in claim 78, wherein said polymer with magnetic material contained therein has a viscosity susceptible to an externally applied magnetic field.

81. The flux switch as claimed in claim 78, wherein said polymer with magnetic material contained therein is substantially in a phase susceptible to an externally applied magnetic field.

82. The flux switch as claimed in claim 78, wherein said polymer with magnetic material contained therein comprises an electro-active liquid crystal with chemical properties susceptible to an externally applied magnetic field.

83. The flux switch as claimed in claim 78, wherein said externally applied magnetic field is an oscillating magnetic field, said oscillating magnetic field generating surface stirring on said electrode.

84. The flux switch as claimed in claim 78, wherein said polymer with magnetic material contained therein comprises a paramagnetic liquid crystal with a viscosity susceptible to an externally applied magnetic field.

85. The flux switch as claimed in claim 78, wherein said polymer with magnetic material contained therein is a paramagnetic liquid crystal having a phase susceptible to an externally applied magnetic field.

86. The flux switch as claimed in claim 78, wherein said non-permanent magnetic microbead material comprises at least one of Fe and Fe oxide containing material having magnetic properties susceptible to an externally applied magnetic field.

87. The flux switch as claimed in claim 78, wherein said non-permanent magnetic microbead material comprises a magnetic material selected from the group consisting of a rare earth metal and a metal oxide with magnetic properties susceptible to an externally applied magnetic field.

88. A device comprising two electrodes, at least one of said two electrodes having a composite coating thereon, said composite coating comprising:

a first material having a first magnetism; and

a second material having a second magnetism, said second material comprising an ion exchange polymer and working in conjunction with said first material to produce magnetic gradients within said composite coating.

89. The device of claim 88, wherein said device comprises one of a flux switch and a fuel cell.