Method for producing a film comprising three-dimensional magnetic microstructures

Patent metadata

Field	Value
Publication number	US-10210995-B2
Application number	US-201314403312-A
Country	US
Kind code	B2
Filing date	May 22, 2013
Priority date	May 22, 2012
Publication date	Feb 19, 2019
Grant date	Feb 19, 2019

Abstract

A method for producing a film including a non-magnetic matrix and a plurality of three-dimensional magnetic microstructures arranged within the matrix according to a predetermined pattern. The method includes providing a master substrate with a magnetically structured face formed from a plurality of magnetic field micro-sources, having a magnetic field gradient of between 10 2 and 10 6 T/m. The method also includes adding magnetic microparticles or nanoparticles to the magnetically structured face of the master substrate, the particles agglomerating into three-dimensional microstructures arranged under an effect of an attractive magnetophoretic force exerted by the magnetic field gradient on the surface of the master substrate. The method further includes depositing, on the magnetically structured face of the master substrate, a matrix made from a non-magnetic material, in such a way as to enclose the arranged microstructures and to form the film and peeling the film from the master substrate.

First claim

The invention claimed is:

1. A method comprising producing a film, wherein said film comprises a non-magnetic matrix and three-dimensional magnetic microstructures arranged within said matrix according to a predetermined pattern, wherein producing said film comprises providing a master substrate, applying particles to a magnetically-structured face of said master substrate, and, after having applied said particles, providing said non-magnetic matrix on said magnetically-structured face and on said magnetic microstructures, and peeling said film from said master substrate, wherein providing said non-magnetic matrix comprises at least one of casting and depositing on said magnetically-structured face and on said magnetic microstructures, wherein said magnetically-structured face is formed from magnetic-field micro-sources having a magnetic-field gradient of between 10 2 and 10 6 teslas per meter, wherein, as a result of having at least one of casted and deposited said non-magnetic matrix, said film forms on said master substrate, wherein said matrix is made from a non-magnetic material, wherein said particles are selected from said group consisting of magnetic microparticles and magnetic nanoparticles, wherein said particles agglomerate into said microstructures, and wherein said microstructures are arranged in response to an attractive magnetophoretic force exerted by a magnetic-field gradient on a surface of said master substrate.

2. The method of claim 1 , further comprising depositing a layer on said magnetically-structured face, wherein depositing said layer occurs before applying said particles, and wherein depositing said layer facilitates subsequent peeling of film from said master substrate.

3. The method of claim 1 , further comprising agitating said master substrate after having applied said particles.

4. The method of claim 1 , further comprising applying a gas jet to said master substrate, wherein applying said gas jet occurs before providing said non-magnetic matrix, and wherein applying said gas jet comprises applying said gas jet in a manner that results in at least one of optimizing a distribution of said particles in relation to said micro-sources and eliminating particles not trapped by a magnetic field of said master substrate.

5. The method of claim 1 , further comprising depositing a liquid-phase ligand on said micro-structures in such a way as to reinforce mechanical cohesion of said particles that form said microstructures, wherein depositing said liquid-phase ligand is carried out prior to providing said non-magnetic matrix on said magnetically-structured face and on said magnetic microstructures.

6. The method of claim 1 , further comprising, after having peeled said film, depositing an electrically conducting material on at least a part of a surface of said film.

7. The method of claim 1 , further comprising winding said film to form a tube.

8. The method of claim 1 , wherein said matrix comprises thermoplastic material, wherein said method further comprises shaping said matrix against a mold by thermoforming, and wherein shaping said matrix occurs after having peeled said film.

9. The method of claim 1 , further comprising, after having provided said matrix on said magnetically-structured face of said master substrate and on said microstructures, allowing said matrix to at least one of harden and reticulate.

10. The method of claim 1 , wherein providing said matrix comprises pouring said matrix on said magnetically-structured face and on said microstructures.

11. The method of claim 1 , further comprising providing said matrix in fluid form, wherein providing said matrix comprises pouring said matrix on said magnetically-structured face and on said microstructures and spreading said matrix, which is in fluid form, over said magnetically-structured face.

12. The method of claim 1 , wherein providing said matrix comprises spin-coating said matrix, which is in fluid form, over said magnetically-structured face.

13. An article of manufacture comprising a use for the film recited in claim 1 , said article of manufacture comprising first and second films assembled together, wherein said first film comprises a cavity, wherein said second film is assembled with said first film to close said cavity and to form a microfluidic channel, and wherein at least one of said first and second films comprises said film.

14. The article of manufacture of claim 13 , wherein said microfluidic channel comprises magnetically-structured walls as a result of said first and second films each having a magnetically-structured surface.

15. The method of claim 1 , further comprising selecting a material from which said matrix is to be made, wherein said material is selected from the group consisting of an elastomer, a thermosetting material, a metal, carbon, an oxide, polydimethylsiloxane, rubber, methyl polymethacrylate, parylene, polystyrene, polyester, epoxy resin, thermosetting phenol formaldehyde resin, a photosensitive resin, SiO 2 , Al 2 O 3 , HfO 2 , a metal, a carbon material, copper, silver, graphite, and diamond-like carbon.

16. The method of claim 1 , wherein said magnetically-structured face of said master substrate has at least one cavity and/or at least one projection, in such a way that, after the peeling, the film has a projection and/or a cavity respectively complementary to the cavity and/or projection of the master substrate.

17. The method of claim 1 , further comprising applying an external magnetic-field to said film in such a way as to magnetize said three-dimensional magnetic microstructures enclosed in said matrix, thereby forming a magnetic device comprising a plurality of micro-magnets.

18. An apparatus for using the film recited in claim 1 , said apparatus comprising a conveyor belt for passage of powder from which magnetic particles are to be recovered, said conveyor belt having a surface that is in contact with said powder, wherein at least a part of said surface comprises said film, wherein said film comprises a non-magnetic matrix and a plurality of three-dimensional magnetic microstructures arranged within said matrix according to a predetermined pattern, said microstructures being formed from an agglomerate of magnetic microparticles or nanoparticles.

Assignees

• Centre Nat Rech Scient
• Univ Grenoble 1

Inventors

• Dempsey Nora
• Dumas-Bouchiat Frédéric
• Zanini Luiz Fernando
• Givord Dominique

Classifications

• H01F41/005

  Impregnating or encapsulating (insulating of windings H01F41/12) · CPC title

• B29D23/00

  Producing tubular articles (B29D24/00 takes precedence) · CPC title

• B01L2300/0816

  Cards, e.g. flat sample carriers usually with flow in two horizontal directions · CPC title

• B29C39/003

  characterised by the choice of material · CPC title

• B01L2200/0668

  Trapping microscopic beads · CPC title