HIGH THERMAL CONDUCTANCE THERMAL INTERFACE MATERIALS BASED ON NANOSTRUCTURED METALLIC NETWORK-POLYMER COMPOSITES

• US 20120187332A1
• Filed: 01/24/2012
• Published: 07/26/2012
• Est. Priority Date: 01/25/2011
• Status: Active Grant

• Current Assignee: International Business Machines Corporation, Rensselaer Polytechnic Institute
• Original Assignee: International Business Machines Corporation, Rensselaer Polytechnic Institute
• Inventors: Iruvanti, Sushumna, Borca-Tasciuc, Theodorian, Plawsky, Joel, Raeisi-Fard, Hafez, Lai, Fengyuan, Pashayi, Kamyar
• Granted Patent: US 9,045,674 B2
• Time in Patent Office: Days
• US Class Current: 252/73
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C08K 2003/0806 Silver
• CPC Class Codes: C08K 3/08 Metals
• CPC Class Codes: C08L 63/00 Compositions of epoxy resins; Compositions of derivatives of epoxy resins
• CPC Class Codes: C09D 139/06 Homopolymers or copolymers of N-vinyl-pyrrolidones
• CPC Class Codes: C09K 5/063 Materials absorbing or liberating heat during crystallisation; Heat storage materials
• CPC Class Codes: C09K 5/14 Solid materials, e.g. powdery or granular

Abstract

A composite structure provides high thermal conductivity as a thermal interface structure with a relatively low filler loading. The composite structure is formed by dispersing nanoparticles in a matrix at a low filler loading, and controlled sintering of the composite structure to induce agglomeration of the nanoparticles into a connected percolating thermally conducting network structure within the matrix.

Claims

1. A composite structure comprising a matrix and a connected percolating thermally conducting network structure embedded within said matrix, said connected percolating network comprising interconnected thermally conducting pathways.

2. The composite structure of claim 1, wherein said connected percolating thermally conducting network structure is a metallic network having a volume fraction from 0.1% to 50% within said composite structure.

3. The composite structure of claim 1, wherein a volume fraction of said metallic network within said composite structure is from 0.1% and 20%, and said composite structure has a thermal conductivity greater than 1.0 W/mK.

4. The composite structure of claim 1, wherein said interconnected thermally conducting pathways comprise nanoparticles that form interconnected structures, said nanoparticles having a dimension in a range from 5 nm to 500 nm.

5. The composite structure of claim 1, wherein said matrix comprises a polymer material.

6. The composite structure of claim 5, wherein said polymer material is selected from an epoxy, modified epoxy, silicone, and rubber.

7. The composite structure of claim 1, further comprising phase change material particles dispersed within said matrix.

8. The composite structure of claim 7, wherein said phase change material particles comprise at least one of phase change salts, lamellar metallo-alkylphosphonates, indium nanoparticles, and low melt element or alloy.

9. The composite structure of claim 1, wherein said matrix comprises a phase change material.

10. The composite structure of claim 9, wherein said phase change material comprises at least one of an organic phase change material, an inorganic phase change material, and a eutectic of at least two phase change materials.

11. A method of forming a compound, said method comprising:

dispersing metallic nanoparticles in a matrix; and

forming a connected percolating thermally conducting network structure embedded within said matrix by inducing agglomeration of said metallic nanoparticles into interconnected thermally conducting pathways.

12. The method of claim 11, wherein said agglomeration of said metallic nanoparticles into said interconnected thermally conducting pathways is performed by an anneal.

13. The method of claim 12, wherein said matrix comprises a polymer and a curing agent before said anneal.

14. The method of claim 12, wherein said anneal is performed at a temperature between 50°

C. and 200°

C.

15. The method of claim 11, wherein said interconnected thermally conducting pathways comprise agglomerated nanoparticles, said nanoparticles having a dimension in a range from 5 nm to 500 nm.

16. The method of claim 11, wherein said metallic nanoparticles have a maximum dimension less than 1 micron.

17. The method of claim 11, wherein said matrix comprises a phase change material.

18. The method of claim 11, wherein phase change material fillers are dispersed in said matrix prior to said agglomeration of said metallic nanoparticles, and are present as embedded structures after said agglomeration of said metallic nanoparticles.

19. The method of claim 11, further comprising functionalizing said metallic nanoparticles before being dispersed in said matrix with a hydrophobic coating that promotes wetting of said metallic nanoparticles within said matrix.

20. The method of claim 11, wherein said agglomeration of said metallic nanoparticles into said interconnected thermally conducting pathways is effected by sintering.