# US 2017/0257974 A1 · Phase change material-carbon nanotube-metal substrate composites for thermal storage and control of heat generating devices

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- Number: US 2017/0257974 A1
- Document ID: US20170257974A1
- Status: Published application
- Kind: A1
- Application number: 15/452,205
- Filed: 2017-03-07
- Published: 2017-09-07
- Earliest claimed: 2016-03-07
- Assignees: Carbice Corporation
- Applicants: Carbice Corporation
- Inventors: Baratunde Cola; Craig Green
- Web page: https://patentgrep.com/patent/US20170257974A1

## CPC

- H05K 7/20: Modifications to facilitate cooling, ventilating, or heating
- B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites
- C09K 5/063: {Materials absorbing or liberating heat during crystallisation; Heat storage materials}
- F28F 21/02: of carbon, e.g. graphite
- F28F 2225/04: for conduits
- F28F 2255/20: with nanostructures
- H05K 7/20336: {Heat pipes, e.g. wicks or capillary pumps}
- H05K 7/2039: {characterised by the heat transfer by conduction from the heat generating element to a dissipating body (arrangements for increasing/decreasing heat-transfer, e.g. fins details, F28F13/00)}
- H05K 7/20509: {Multiple-component heat spreaders; Multi-component heat-conducting support plates; Multi-component non-closed heat-conducting structures}
- H10K 85/221: {Carbon nanotubes}
- Y10S 977/742: Carbon nanotubes, CNTs
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16)
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

Phase change material-carbon nanotube-metal substrate composites and methods of making and using thereof are described herein. Such composites allow for thermal storage and passive or combined active/passive thermal control of heat generating sources, such as in electronic devices.

## Claims

### Claim 1

A composite material comprising:
a phase change material;
vertically aligned carbon nanotube array supported on a substrate; and
wherein all or substantially all void space present within the vertically aligned carbon nanotubes (CNTs) is filled by the phase change material.

### Claim 2 (depends on 1)

The composite material of claim 1, wherein the substrate is comprises a metal.

### Claim 3 (depends on 1)

The composite material of claim 1, wherein the composite material is in thermal communication with a heat generating source.

### Claim 4 (depends on 3)

The composite material of claim 3, wherein the heat generating source is an electronic device selected from the group consisting of a microchip, power conversion device, radio frequency communications module, and optoelectronics device.

### Claim 5 (depends on 1)

The composite material of claim 1, wherein the composite comprises a stack of two or more tiers of the vertically aligned CNT arrays supported on the substrates.

### Claim 6 (depends on 5)

The composite material of claim 5, wherein the interfacing tiers between the two or more of the vertically aligned CNTs are interdigitated within one another.

### Claim 7 (depends on 1)

The composite material of claim 1, wherein the phase change material is infiltrated into the vertically aligned CNT array via application of the phase change material and a solvent solution mixture to the carbon nanotube array and subsequently the solvent is evaporated following infiltration.

### Claim 8 (depends on 1)

The composite material of claim 1, wherein the phase change material is infiltrated into the vertically aligned CNT array through capillary action or wicking of the phase change material.

### Claim 9 (depends on 1)

The composite material of claim 1, wherein the surface energy of the vertically aligned CNT array is modified through deposition of metals or ceramics.

### Claim 10 (depends on 1)

The composite material of claim 1, wherein the phase change material is infiltrated into the array as a solid particulate form.

### Claim 11 (depends on 10)

The composite material of claim 10, wherein the solid particulates are sized such that their average diameter is smaller than the nanotube-to-nanotube spacing within the CNT array.

### Claim 12 (depends on 1)

The composite material of claim 1, wherein the phase change material is infiltrated into the vertically aligned CNT array via electro-deposition of the phase change material onto the surface of the vertically aligned CNTs.

### Claim 13 (depends on 4)

The composite material of claim 4, wherein the phase change material melts or solidifies at a temperature at or near the operating temperature of the electronic device.

### Claim 14 (depends on 4)

The composite material of claim 4, wherein the phase change material melts or solidifies at a temperature above the operating temperature of the electronic device.

### Claim 15 (depends on 1)

The composite material of claim 1, wherein the phase change material further provides structural integrity to the vertically aligned CNT array.

### Claim 16 (depends on 1)

The composite material of claim 1, wherein the phase change material imparts adhesive properties to the metal substrate.

### Claim 17 (depends on 1)

The composite material of claim 1, wherein the vertically aligned CNT array provides stress relief for the phase change material by providing structural reinforcement and load bearing when the composite material is subjected to compression, tension, or both.

### Claim 18 (depends on 1)

The composite material of claim 1, wherein the composite material is flexible allowing it to be contoured to fit internal geometry of an electronic package and to have thermal communication with more than one heat generating surface at a time.

### Claim 19 (depends on 1)

The composite material of claim 1, wherein the composite material is present within a container.

### Claim 20 (depends on 4)

The composite material of claim 4, wherein the composite material is in thermal communication with the electronic device and the surrounding atmosphere.

### Claim 21 (depends on 20)

The composite material of claim 20, wherein the composite material is in thermal communication with the electronic device and in thermal communication with a secondary thermal solution selected from a heat sink, cold plate, spreader, or heat pipe.

### Claim 22 (depends on 20)

The composite material of claim 20, wherein the composite material improves heat transfer between the electronic device and the secondary thermal solution.

### Claim 23 (depends on 1)

The composite material of claim 1, wherein the substrate acts as an extended surface area for heat transfer.

### Claim 24 (depends on 1)

The composite material of claim 1, wherein the carbon nanotubes of the array efficiently reject heat to surroundings via radiation.

### Claim 25 (depends on 1)

The composite material of claim 1, wherein the substrate provides the composite material a higher in plane thermal conductivity than cross plane thermal conductivity.

### Claim 26 (depends on 1)

The composite material of claim 1, wherein the composite material is flexible and conformable to a three dimensional surface.

### Claim 27 (depends on 4)

The composite material of claim 4, wherein the composite material is in thermal communication with the electronic device and the device operates in transient or limited duration fashion.

### Claim 28 (depends on 4)

The composite material of claim 4, wherein power consumption of the electronic device may be temporarily enhanced to improve performance during a high demand activity.

### Claim 29 (depends on 1)

The composite material of claim 1, wherein at least a portion of the phase change material is a thermoplastic adhesive which is applied conformal to the carbon nanotube array.

### Claim 30 (depends on 29)

The composite material of claim 29, wherein the thermoplastic adhesive is a coating having a thickness of less 5,000 nm and wherein the thermoplastic adhesive coating does not add thermal resistance to the composite material.

### Claim 31 (depends on 1)

The composite material of claim 1, wherein the composite material provides shielding against electromagnetic interference.

### Claim 32 (depends on 1)

The composite material of claim 1, wherein the composite simultaneously provides electromagnetic interference shielding and heat spreading, heat storage, heat transfer, or other heat dissipation properties.

### Claim 33

A method of making a composite material, the method comprising:
providing one or more vertically aligned carbon nanotube arrays supported on a substrate; and
infiltrating a phase change material to the vertically aligned carbon nanotube arrays supported on a substrate wherein all or substantially all void space present within the vertically aligned carbon nanotubes (CNTs) is filled by the phase change material.

### Claim 34 (depends on 33)

The method of claim 33, wherein the phase change material wets the CNTs and infiltrates the CNT array via capillary action or wicking action.

### Claim 35 (depends on 33)

The method of claim 33, wherein the phase change material is infiltrated via spray coating or powder coating.

### Claim 36 (depends on 33)

The method of claim 33, wherein the carbon nanotube arrays are coated with, dispersed within, infiltrated by, or filled in with the phase change material selected from polymeric, non-polymeric, low melting temperature metal or metal alloys, or combinations thereof.

### Claim 37 (depends on 33)

The method of claim 33, wherein the phase change material is an oligomeric or polymeric material.

### Claim 38 (depends on 38)

The method of claim 38, wherein the polymeric material is an adhesive.

### Claim 39 (depends on 38)

The method of claim 38, wherein the adhesive is selected from the group consisting of polyurethanes, nylons, styrenic block copolymers, olefins, poly(olefins), thermoplastic vulcanizates, polyesters, copolyesters, polyamides, and combinations thereof.

### Claim 40 (depends on 33)

The method of claim 33, wherein the phase change material conformally coats the carbon nanotubes.

### Claim 41 (depends on 33)

The method of claim 33, wherein the phase change material is infiltrated into the vertically aligned CNT array via application of a phase change material and solvent solution mixture to the array and subsequently the solvent is evaporated following infiltration.

### Claim 42 (depends on 33)

The method of claim 33, further comprising the step of:
stacking at least two infiltrated vertically aligned CNT arrays supported on the substrates.

### Claim 43 (depends on 43)

The method of claim 43, wherein the stacked arrays form interfacing tiers between the two or more of the vertically aligned CNTs which are interdigitated within one another.

### Claim 44 (depends on 44)

The method of claim 44, wherein the number of interfacing tiers in the stack is 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25.

### Claim 45 (depends on 44)

The method of claim 44, wherein degree of interdigitation between interfacing tiers is at least about 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 99.9%.

### Claim 46 (depends on 1)

A device comprising the composite material defined in claim 1.