Networked thermal interface materials and methods

Abstract

Composite materials that may include a matrix material, a first plurality of particles, a second plurality of particles, and a third plurality of particles. The third plurality of particles may include gel particles. The first plurality of particles and the second plurality of particles may include particles having different shapes, such as shapes that may facilitate the formation of an interconnected network of the particles. Methods for forming composite materials, and methods of using composite materials, such as using the composite materials to improve heat transfer.

Description

NETWORKED THERMAL INTERFACE MATERIALS AND METHODSCross Reference to Related Applications

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 676,518, filed July 29, 2024, which is incorporated by reference herein.Field of the Disclosure

[0002] This disclosure relates to thermal interface materials, such as pastes, that may include gel particles and conductive particles of different shapes, and methods for forming and using thermal interface materials.Background

[0003] Thermal interface materials (TIM) are substances that can be configured to bridge gaps between two surfaces having different temperatures, thereby providing one or more improvements, such as an improved heat transfer rate, effective adhesion, etc. Therefore, TIMs can play an important role in reducing or minimizing energy loss, and, in some instances, enhancing the overall performance of systems.

[0004] TIMs can have various forms, including, but not limited to, thermal pads, thermal greases, gap fillers, thermal pastes, thermal gels, etc. Generally, TIMs may include a matrix phase, a filler material, and other additives. The matrix phases ty pically include viscoelastic polymers, and the filler materials can include a wide range of materials, such as metals, ceramics, and hybrid materials.

[0005] There remains a need for improved composite materials, such as TIMs, that have or provide one or more improved properties, such as an improved thermal conductivity and / or an enhanced heat transfer rate.Brief Summary

[0006] Provided herein are methods of forming or using composite materials, and composite materials, embodiments of which have one or more of the foregoing properties, such as improved thermal conductivities. For example, embodiments of the composite materials described herein may include gel particles and filler particles, and at least a portion of the filler particles, such as flake-shaped particles, may be arranged on all or some of the gel particles, thereby contributing to the formation of an interconnectednetwork of differently-shaped filler particles, which can improve — to a surprising and unexpected extent — the thermal conductivities of embodiments of the composite materials relative to comparative composite materials that are similar, if not identical, to the composite materials described herein, but for the inclusion of the gel particles.

[0007] In one aspect, composite materials are provided. In some embodiments, the composite materials include a matrix material, a first plurality of particles, a second plurality7of particles, and a third plurality' of particles. The third plurality' of particles, which may include gel particles, may interact with the first plurality of particles in a manner that provides one or more advantages. For example, one or more particles of the first plurality of particles may be arranged on a surface of a particle of the third plurality of particles. In some embodiments, a shape of the first plurality' of particles differs from a shape of the second plurality of particles. The shape of the second plurality of particles may be effective to form an interconnected network in the composite material, due, for example, to points of physical contact between (i) at least a portion of the first plurality of particles, which may be advantageously arranged on the third plurality' of particles, and (ii) at least a portion of the second plurality' of particles.

[0008] In another aspect, methods of forming composite materials are provided. In some embodiments, the methods include providing a first plurality of particles, wherein the first plurality of particles includes flake-shaped particles; providing a second plurality' of particles, wherein the second plurality' of particles includes rod-shaped particles; providing a third plurality of particles that include a gel; contacting the first plurality of particles and the third plurality of particles to form a first intermediate material; contacting the second plurality of particles and the first intermediate material to form a second intermediate material; and contacting a matrix material and the second intermediate material to form the composite material. The providing of the third plurality' of particles may include contacting a liquid and a plurality of particles of a solid, e.g., a polymer, and mixing the plurality of particles of the solid and the liquid for a time effective to form the third plurality' of particles.

[0009] In yet another aspect, methods of using composite materials are provided, such as using composite materials to improve heat transfer. In some embodiments, the methods include providing a composite matenal described herein, and arranging the composite material between and in contact with a surface of a first object and a surface ofa second object. The surface of the first object and the surface of the second object may be at different temperatures prior to the arranging of the composite material.

[0010] Additional aspects will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the aspects described herein. The advantages described herein may be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive.Brief Description of the Drawings

[0011] FIG. 1 is a schematic of an embodiment of a composite material.

[0012] FIG. 2A depicts the thermal conductivity of a reference composite material.

[0013] FIG. 2B depicts the thermal conductivity of an embodiment of a composite material.Detailed Description

[0014] Provided herein are composite materials, such as pastes, methods of forming composite materials, and methods of using composite materials, such as using composite materials to improve heat transfer among two or more objects.Composite Materials

[0015] Composite materials are provided herein, which may include a matrix material, a first plurality of particles, a second plurality of particles, and a third plurality of particles. A shape of the first plurality of particles may differ from a shape of the second plurality of particles. The first plurality of particles, the second plurality of particles, and the third plurality of particles, independently, may be dispersed evenly or unevenly in the matrix materials.

[0016] The first plurality of particles, the second plurality of particles, and the third plurality of particles may form an interconnected network in the composite materials due to points of physical contact between (i) at least a portion of the first plurality of particles and at least a portion of the third plurality of particles, (ii) at least a portion of the first plurality of particles and at least a portion of the second plurality of particles, or (iii) a combination thereof.

[0017] An embodiment of a composite material 100 that features an interconnected network 110 of the first 120, second 130, and third 140 pluralities of particles is depicted at FIG. 1. In the embodiment depicted at FIG. 1, the first plurality' of particles are flake particles 120, the second plurality of particles are rod-shaped particles 130 (also referred to as fiber materials), and the third plurality' of particles are gel particles 140. The first 120, second 130, and third 140 pluralities of particles are dispersed in a matrix material 150 and physically contact each other at multiple points. For example, the third plurality7of particles 140 contacts the first plurality7of particles 120. because, in the embodiment depicted at FIG. 1, several flake particles 120 contact the surface of each gel particle 140. As a further example, the first plurality of particles 120 and the second plurality' of particles 130 contact each other, because the rod-shaped particles 130 contact the flake particles 120 that, in turn, contact the gel particles 140. Although each end of the rodshaped particles 130 contacts a flake-shaped particle 120 in FIG. 1, it should be noted that FIG. 1 is merely a schematic, and it is envisioned that, in some instances, not every particle will be in physical contact with another particle (a) at all and / or (b) in the manner depicted at FIG. 1. For example, one or more of the first plurality of particles 120 may be in direct contact with one or more other particles of the first plurality7of particles (e.g., two flake particles in contact with the surface of the same gel particle may contact each other, and / or a flake particle that contacts a first gel particle may contact a flake particle that contacts a second gel particle). Likewise, one or more of the second plurality7of particles 130 may be in direct contact with one or more other particles of the second plurality of particles (e.g.. a first rod particle may contact a second rod particle) and / or the third plurality7of particles 140 (e.g., a rod particle may contact a gel particle). Also, one or more of the first plurality of particles and / or one or more of the second plurality7of particles and / or one or more of the third plurality of particles may be physically isolated and not in contact with other particles of any kind.

[0018] Due to their shapes and / or other features described herein, the first plurality of particles, the second plurality of particles, the third plurality7of particles, or a combination thereof may provide conductive pathways in a composite material, due at least in part to points of physical contact between the particles, such as depicted at FIG. 1. The conductive pathways may be thermally conductive pathways. It should be noted that the third plurality of particles may include non-conductive particles, and, in such instances, the third plurality of particles may contribute to the formation of conductivepathways because other particles, especially conductive particles, which may include the first plurality of particles, may be arranged on the third plurality of particles, as explained herein.

[0019] The composite materials may be in any physical form and / or any phase of matter, for example, a solid, semi-solid, or fluid. In some embodiments, the composite material is a paste.

[0020] In some embodiments, the composite materials have thermal conductivities that exceed, to a surprising extent, the thermal conductivities of comparative composite materials. For example, embodiments of the composite materials described herein may have a thermal conductivity' (W / m-1K"1) that is at least 5 %, at least 10 %, at least 15 %, at least 20 %, at least 25 %, at least 30 %, at least 40 %, at least 50 %, or at least 60 % greater than a thermal conductivity (W / m’1K1) of a comparative composite material. For example, if a comparative composite material has a thermal conductivity of 10 units, and a composite material has a thermal conductivity of 16 units, then the composite material has a thermal conductivity that is 60 % greater than the thermal conductivity' of the comparative composite material.

[0021] The phrase ‘"comparative composite material"’, as used herein, refers to a material that includes a first plurality of particles and a second plurality of particles, but not a third plurality of particles (see, e.g., the reference composite material of Example 1), wherein the first plurality' of particles and the second plurality of particles are present in a comparative composite material at concentrations that are within about 10 wt%, about 5 wt%, or about 1 wt% of the concentration of the first plurality of particles and the second plurality' of particles, respectively, in the composite material. For example, if a comparative composite material includes about 35 wt% to about 45 wt% of the first plurality of particles and about 0. 1 wt% to about 10 wt% of the second plurality of particles, and a composite material includes about 30 wt% of the first plurality’ of particles and about 5 wt% of the second plurality of particles, then the comparative composite material includes the first plurality of particles and the second plurality of particles at concentrations that are within about 5 wt% of the respective concentrations of the first plurality of particles and the second plurality of particles in the composite material.

[0022] When an embodiment of a composite material described herein and a comparative composite material are compared, then the embodiment of the compositematerial and the comparative composite material may include the same matrix material or similar matrix materials.

[0023] In some embodiments, the composite materials described herein unexpectedly have a thermal impedance (K m2W-1) that is at least 5 %, at least 10 %, at least 15 %, at least 20 %, at least 25 %, at least 30 %, at least 40 %, at least 50 %, or at least 60 % less than athermal impedance (K m2W-1) of a comparative composite material. For example, if a comparative composite material has a thermal impedance of 10 units, and a composite material has a thermal impedance of 6 units, then the composite material has a thermal conductivity that is 40 % less than the thermal impedance of the comparative composite material.Methods of Forming Composite Materials

[0024] Also provided herein are methods of forming composite materials. In some embodiments, the methods include providing a first plurality of particles; providing a second plurality of particles: providing a third plurality of particles; and contacting the first plurality of particles and the third plurality of particles, which may form a first intermediate material. The contacting of the first plurality of particles and the third plurality of particles may be achieved using any known technique, and may be effective to achieve an advantageous relationship between the first and third pluralities of particles. For example, at least a portion of the first plurality of particles may be arranged on the third plurality7of particles, as described herein. One or more particles of the first plurality of particles may adhere to a particle of the third plurality of particles.

[0025] The methods also may include contacting the second plurality of particles and the first intermediate material (which includes the first plurality of particles and the third plurality of particles) to form a second intermediate material. The third plurality7of particles, as explained herein, may have surfaces that are in contact with the first plurality of particles, and the first, second, and third plurality of particles may be contacted to form an interconnected network of the first, second, and third plurality of particles.

[0026] The methods also may include contacting a matrix material and the second intermediate material to form the composite material. The contacting of the matrix material and the first, second, and third plurality of particles may include mixing the matrix material and the first, second, and third pluralities of particles, and the mixing, as described herein, may impart a force to the first, second, and third pluralities of particlesthat does not undesirably impact the interconnected network that may be formed by the first, second, and third pluralities of particles.

[0027] The providing of the third plurality of particles may be achieved using any known technique. In some embodiments, the providing of the third plurality of particles includes contacting a liquid and a plurality of particles of a solid, e.g., a polymer, and mixing the plurality of particles of the solid and the liquid for a time effective to form the third plurality of particles. For example, the plurality of particles of a polymer may be mixed with the liquid to form gel particles, which may include mixing the polymer particles and the liquid for a time effective to achieve a desired level of swelling of the polymer particles. The initial size and / or character of the polymer particles, the liquid, the mixing time and / or temperature, or a combination thereof may be selected to achieve gel particles of a desirable size and / or shape. The size and / or shape of the gel particles may be selected based on the dimensions of the first plurality of particles in order to facilitate an advantageous relationship between the first and third pluralities of particles.

[0028] Upon formation of the third plurality of particles, at least a portion of the liquid, such as an excess portion, may be separated, using any technique, from the third plurality of particles. In some embodiments, the methods include separating a portion of the liquid from the third plurality of particles (such as via filtration, evaporation, or otherwise) before (i) the contacting of the first and third pluralities of particles, (ii) the contacting of the first, second, and third pluralities of particles, (iii) the contacting of the matrix material and the first, second, and third pluralities of particles, or (iv) a combination thereof. Additionally or alternatively, any one or more of the elements of the methods described herein may occur in the presence of the liquid. Therefore, additional amounts of liquid may be added to facilitate desirable mixing of any one or more components.

[0029] Any one or more of the contacting procedures of the methods described herein may include mixing the one or more components, such as the first plurality of particles and the third plurality of particles. The mixing may include the application of any agitating force(s), such as stirring, which may be achieved with any equipment, such as a dynamic mixer (e.g., a rotary mixer) and / or a static mixer.

[0030] The mixing of the first plurality of particles, the second plurality of particles, and the third plurality of particles (in the presence or absence of a matrix material), may impart a force to the first plurality’ of particles, the second plurality ofparticles, and the third plurality of particles that does not undesirably reduce and / or alter (A) the points of contact between (i) at least a portion of the first plurality of particles and at least a portion of the third plurality of particles, and / or (ii) at least a portion of the first plurality of particles and at least a portion of the second plurality of particles, or (B) the interconnected network formed by at least a portion of the first plurality of particles, at least a portion of the second plurality of particles, and / or at least a portion of the third plurality of particles.

[0031] In some embodiments, the third plurality of particles is formed by mixing a plurality of particles of a solid (e.g., polymer) and a liquid, and the mixing of the plurality of particles of the solid and the liquid occurs for a time of about 1 minute to about 30 minutes, about 1 minute to about 20 minutes, or about 5 minutes to about 10 minutes. In some embodiments, the mixing of the first plurality of particles, the second plurality of particles, the third plurality of particles, or a combination thereof (in the absence or presence of a matrix material) includes stirring with a rotary mixer at about 5 rpm to about 50 rpm, about 10 rpm to about 50 rpm, about 20 rpm to about 50 rpm, about 30 rpm to about 50 rpm, about 40 rpm to about 50 rpm, about 5 rpm to about 40 rpm, about 5 rpm to about 30 rpm. about 5 rpm to about 20 rpm, or about 5 rpm to about 10 rpm. In some embodiments, the mixing of the first plurality of particles, the second plurality of particles, the third plurality of particles, or a combination thereof (in the absence or presence of a matrix material) occurs for about 30 seconds to about 5 minutes, about 1 minute to about 5 minutes, about 2 minutes to about 5 minutes, about 3 minutes to about 5 minutes, about 4 minutes to about 5 minutes, about 30 seconds to about 4 minutes, about 30 seconds to about 3 minutes, about 30 seconds to about 2 minutes, or about 30 seconds to about 1 minute. In some embodiments, the mixing of the matrix material, the first plurality of particles, the second plurality of particles, and the third plurality of particles includes stirring with a rotary mixer at about 5 rpm to about 60 rpm, about 10 rpm to about 60 rpm, about 20 rpm to about 60 rpm, about 30 rpm to about 60 rpm, about 40 rpm to about 60 rpm, about 50 rpm to about 60 rpm, about 5 rpm to about 60 rpm, about 5 rpm to about 50 rpm, about 5 rpm to about 40 rpm, about 5 rpm to about 30 rpm, about 5 rpm to about 20 rpm, or about 5 rpm to about 10 rpm. In some embodiments, the mixing of the matrix material, the first plurality of particles, the second plurality of particles, and the third plurality of particles occurs for about 10 minutes to about 30 minutes, about 10 minutes to about 25 minutes, about 10 minutes to about 20 minutes, about 10 minutes to about 15minutes, about 15 minutes to about 30 minutes, about 20 minutes to about 30 minutes, or about 25 minutes to about 30 minutes.

[0032] In some embodiments, the methods include contacting the first, second, and / or third pluralities of particles and an adhesive. In some embodiments, the adhesive is soluble in the liquid that may be used to prepare the third plurality of particles, and the adhesive and the liquid may be optionally mixed for a time effective to dissolve, completely or partially, the adhesive in the liquid, such as a time of about 5 to about 20 minutes, or about 10 minutes to about 15 minutes.Methods of Using Composite Materials

[0033] Also provided herein are methods of using composite materials, such as any of those described herein. In some embodiments, the methods include providing a composite material, such as any of those described herein; and arranging the composite material between and in contact with a surface of a first object and a surface of a second object. The surface of the first object and the surface of the second object may be at different temperatures prior to the arranging of the composite material. The temperature difference between the different temperatures of the surface of the first object and the surface of the second object may be at least 5 °C, at least 10 °C, at least 20 °C, at least 30 °C, at least 40 °C, or at least 50 °C.

[0034] The first object and the second object generally may be formed of any material (e.g., metal, ceramic, plastic, glass, etc.) and have any shape. The first object and / or the second object may be part of an appliance, such as an appliance configured for heating and / or cooling a space (e.g., a furnace, boiler, air conditioner, heat pump, etc.), a tanked or tankless water heater, etc. The first object, for example, may be a pipe, channel, or other heat exchanger component. In some implementations, the first object is a condenser in a refrigeration circuit, such as for a heat pump water heater. For example, the first object may be a microchannel condenser in the refrigeration circuit. The second object may be a tank. For example, the tank may be a hot water tank arranged for heat exchange with the first object (e.g., microchannel condenser of a heat pump water heater).First Plurality of Particles

[0035] In some embodiments, the first plurality of particles includes flake-shaped particles, which may be referred to as “flake particles”. Each particle of the first plurality of particles may have a first surface, a second surface opposite the first surface, and a thickness.

[0036] The first plurality of particles may include particles having different dimensions or one or more substantially uniform dimensions (i.e., thicknesses (and / or other dimension) within ± 5 % of each other) (see, for example, FIG. 1). Dimensions are "‘substantially uniform” herein when the dimensions are within ± 5 % or ± 1 % of each other. When the first plurality of particles have a first surface, a second surface opposite the first surface, and a thickness, the first plurality of particles may have an average thickness of about 1 pm to about 200 pm, about 10 pm to about 200 pm, about 10 pm to about 150 pm, about 10 pm to about 100 pm, about 10 pm to about 50 pm, about 50 pm to about 200 pm, about 100 pm to about 200 pm, or about 150 pm to about 200 pm, and / or an average largest dimension of the first surface of about 1 pm to about 200 pm, about 10 pm to about 200 pm, about 10 pm to about 150 pm, about 10 pm to about 100 pm, about 10 pm to about 50 pm, about 50 pm to about 200 pm, about 100 pm to about 200 pm. or about 150 pm to about 200 pm. The first plurality of particles may feature any ratio of the average largest dimension of the first surface to the average thickness. In some embodiments, a ratio of the average largest dimension of the first surface to the average thickness is about 100: 1 to about 1:1, about 50: 1 to about 1 : 1, about 40: 1 to about 1: 1, about 30: 1 to about 1: 1. about 20: 1 to about 1: 1, about 10: 1 to about 1: 1, about 100: 1 to about 2: 1, about 50: 1 to about 2: 1, about 40: 1 to about 2: 1, about 30: 1 to about 2: 1, about 20: 1 to about 2: 1, or about 10: 1 to about 2: 1 (average largest dimension of the first surface : average thickness).

[0037] One or more dimensions of the first plurality of particles may be selected based on the sizes and / or shapes of the third plurality of particles. For example, the dimensions of the first plurality of particles may be selected to facilitate contacting each particle of the third plurality of particles with a desired number of particles of the first plurality of particles.

[0038] The first plurality of particles generally may be formed of any one or more materials that imparts one or more desired properties to a composite material. In some embodiments, the first plurality of particles is formed at least in part of a first metal, a first ceramic, or a combination thereof. The first metal may include aluminum, silver, or a combination thereof. The first ceramic may include alumina, aluminum nitride, zinc oxide, silicon carbide, silicon nitride, beryllium oxide, or a combination thereof. In some embodiments, the first plurality7of particles is formed at least in part of graphene, carbon nanotubes (e.g., a buck paper, a nanoribbon, etc.), or a combination thereof.

[0039] A first plurality of particles generally may be present in a composite material at any concentration, such as a concentration that provides an interconnected network of particles, as described herein. In some embodiments, the first plurality of particles is present in a composite material at an amount of about 0. 1 wt% to about 50 wt%, about 5 wt% to about 45 wt%, about 10 wt% to about 40 wt%, about 20 wt% to about 40 wt%, about 20 wt% to about 30 wt%, about 20 wt% to about 25 wt%, about 23 wt% to about 25 wt%, about 25 wt% to about 35 wt%, or about 25 wt% to about 30 wt%, based on the weight of the composite material.Second Plurality of Particles

[0040] In some embodiments, the second plurality of particles includes rod-shaped particles. The second plurality of particles may include particles having different dimensions or substantially uniform dimensions (e g., lengths within ± 5 % of each other). When the second plurality of particles includes rod-shaped particles, each particle of the second plurality of particles may have a length (or height) and a width (or diameter when the rod-shaped particles are cylindrical).

[0041] In some embodiments, the second plurality of particles has an average width (or diameter) of about 1 pm to about 400 pm, about 40 pm to about 400 pm, about 1 pm to about 300 pm, about 40 pm to about 300 pm, about 1 pm to about 200 pm, about 40 pm to about 200 pm, about 1 pm to about 100 pm, about 40 pm to about 100 pm, about 100 pm to about 400 pm, about 200 pm to about 400 pm, or about 300 pm to about 400 pm. and / or an average length (or height) of about 1 pm to about 2,000 pm. about 1 pm to about 1,500 pm, about 1 pm to about 1,000 pm. about 1 pm to about 500 pm, about 1 pm to about 500 pm, about 1 pm to about 400 pm, about 1 pm to about 300 pm, about 10 pm to about 200 pm, about 10 pm to about 100 pm, about 10 pm to about 50 pm, about 50 pm to about 500 pm, about 100 pm to about 500 pm, about 200 pm to about 500 pm. about 300 pm to about 500 pm, or about 400 pm to about 500 pm.

[0042] When the second plurality of particles includes rod-shaped particles, the rod-shaped particles generally may feature any ratio of length to width, including a ratio that achieves an effective reduction of the Gibbs energy barrier, as described herein. In some embodiments, a ratio of the average length (or height) to the average width (or diameter) is about 50: 1 to about 1: 1, about 40: 1 to about 1: 1. about 30: 1 to about 1: 1. about 20: 1 to about 1 :1, about 10: 1 to about 1: 1, about 5: 1 to about 1: 1, about 50: 1 to about 2:1, about 40:1 to about 2: 1, about 30: 1 to about 2: 1, about 20: 1 to about 2: 1, about10: 1 to about 2: 1, about 5: 1 to about 2: 1 , about 50: 1 to about 5: 1 , about 40: 1 to about 5:1 , about 30: 1 to about 5:1, about 20: 1 to about 5: 1, about 12: 1 to about 5: 1, about 10: 1 to about 5: 1, or about 5: 1 to about 5: 1 (average length (or height) : average width (or diameter)).

[0043] The second plurality of particles generally may be formed of any one or more materials that imparts one or more desired properties to a composite material. In some embodiments, the second plurality of particles is formed at least in part of a second metal, a second ceramic, or a combination thereof. The first metal of the first plurality of particles and the second metal of the second plurality’ of particles may be the same or different. The first ceramic of the first plurality of particles and the second ceramic of the second plurality of particles may be the same or different.

[0044] The second metal may include aluminum, silver, or a combination thereof. The second plurality of particles may be formed at least in part from a wool, such as a metal wool (e.g., aluminum wool), that has been processed to reduce the dimensions of the wool, particularly the lengths of each strand of the wool. The second ceramic may include alumina, aluminum nitride, zinc oxide, silicon carbide, silicon nitride, bery llium oxide, or a combination thereof. In some embodiments, the second plurality of particles is formed at least in part of graphene, carbon nanotubes (e.g., a buckypaper, a nanoribbon, etc.), or a combination thereof.

[0045] A second plurality of particles generally may be present in a composite material at any concentration, such as a concentration that provides an interconnected network of particles, as described herein. In some embodiments, the second plurality of particles is present in the composite material at an amount of about 0.001 wt% to about 30 wt%, about 0.1 wt% to about 25 wt %, about 0. 1 wt% to about 20 wt%, about 0. 1 wt% to about 15 wt%, about 0. 1 wt% to about 10 wt%, about 1 wt% to about 10 wt%, about 2 wt% to about 8 wt%, about 4 wt% to about 6 wt%. or about 5 wt%, based on the weight of the composite material.

[0046] The first plurality of particles and the second plurality of particles generally may be present in a composite material at any ratio, including a ratio that provides an interconnected network of particles, as described herein. In some embodiments, a ratio of the concentrations (wt%) of the first plurality of particles to the second plurality of particles in the composite material is about 2: 1 to about 10: 1, about 2: 1 to about 8: 1, about4: 1 to about 8: 1 , about 4: 1 to about 7:1 , about 4: 1 to about 6: 1 , or about 5: 1 to about 6: 1 (first plurality of particles (wt%) : second plurality7of particles (wt%)).

[0047] The second plurality of particles may be at least partially coated with an adhesive, as described herein. The selected shape of the second plurality of particles may be effective to reduce the Gibbs energy barrier for nucleation (e.g., heterogeneous nucleation) of the adhesive from a liquid (e.g., a solution of the adhesive) to surfaces of the second plurality of particles, which may result in a substantially uniform deposition of the adhesive on the surfaces.Third Plurality of Particles

[0048] In some embodiments, the third plurality of particles includes a gel. In other words, the third plurality of particles may include particles formed entirely or partially of a gel. The term ' gel" is used herein in a manner that is consistent with its common definition, and includes colloidal suspensions in which a liquid is dispersed in a solid, or vice versa.

[0049] In some embodiments, the third plurality of particles are derived from a solid, such as a polymer, and a liquid. The term “polymer”, as used herein, includes any component formed of two or more repeat units, wherein the repeat units are identical or different; therefore, the term “polymer”, as used herein, includes homopolymers, copolymers (e.g., a terpolymer, block copolymer, etc.), oligomers, or any combination thereof, of any configuration, such as linear, crosslinked, star, comb, or any combination thereof. In some embodiments, the polymer includes repeat units derived from an alkene monomer (e.g., a C2-C6 alkene monomer), a styrene monomer, or a combination thereof. In some embodiments, the polymer includes a styrene-ethylene / butylene-styrene (SEBS) copolymer. As used herein, the phrase “styrene monomer” refers styrene or a styrene derivative, such as a substituted styrene (e.g., an alkoxy substituted styrene).

[0050] The solid, e.g., polymer, generally may be combined with any liquid that is capable of forming a gel. The liquid may be an organic liquid, such as an alkane (e.g., a C3-C10 alkane). In some embodiments, the liquid is hexane.

[0051] The third plurality of particles generally may have any dimensions and / or shape. The third plurality of particles, for example, may be spherical, non-spherical, or a combination thereof. In some embodiments, the dimensions and / or shape of the third plurality' of particles is selected to achieve a desired relationship between the first and third pluralities of particles, such as by facilitating the arrangement of a desired number offlake-shaped particles of the first plurality of particles on each particle of the third plurality of particles. When the third plurality of particles includes a gel, the first plurality of particles may adhere to the third plurality' of particles, due, for example, to capillary action of a liquid of the gel. The advantageous relationship between the first and third pluralities of particles may, in some instances, provide one or more isotropic material properties.

[0052] In some embodiments, the third plurality' of particles has an average largest dimension of about 1 pm to about 1,000 pm, about 1 pm to about 800 pm, about 1 pm to about 600 pm, about 1 pm to about 500 pm, about 10 pm to about 500 pm, about 20 pm to about 500 pm, about 30 pm to about 500 pm, about 40 pm to about 500 pm, about 50 pm to about 500 pm, about 100 pm to about 500 pm, about 200 pm to about 500 pm, about 300 pm to about 500 pm, about 400 pm to about 500 pm, about 50 pm to about 400 pm, about 50 pm to about 300 pm. about 50 pm to about 200 pm. about 50 pm to about 100 pm, about 1 pm to about 200 pm, about 1 pm to about 100 pm, about 1 pm to about 90 pm, about 1 pm to about 80 pm, about 1 pm to about 70 pm, about 1 pm to about 60 pm, about 1 pm to about 50 pm, about 1 pm to about 40 pm, about 1 pm to about 30 pm, about 1 pm to about 20 pm, about 1 pm to about 10 pm, about 10 pm to about 100 pm. about 20 pm to about 100 pm, about 30 pm to about 100 pm, about 40 pm to about 100 pm, about 50 pm to about 100 pm, about 60 pm to about 100 pm, about 70 pm to about 100 pm, about 80 pm to about 100 pm, or about 90 pm to about 100 pm.

[0053] In some embodiments, the polymer of the third plurality of particles — prior to swelling upon contacting the liquid — is in the form of particles, and has an average largest dimension of about 1 pm to about 1 ,000 pm, about 1 pm to about 800 pm, about 1 pm to about 600 pm, about 1 pm to about 400 pm, about 1 pm to about 200 pm, about 1 pm to about 100 pm, about 1 pm to about 90 pm, about 1 pm to about 80 pm, about 1 pm to about 70 pm. about 1 pm to about 60 pm, about 1 pm to about 50 pm, about 1 pm to about 40 pm, about 1 pm to about 30 pm, about 1 pm to about 20 pm, about 1 pm to about 10 pm, about 10 pm to about 100 pm, about 20 pm to about 100 pm, about 30 pm to about 100 pm, about 40 pm to about 100 pm, about 50 pm to about 100 pm, about 60 pm to about 100 pm, about 70 pm to about 100 pm, about 80 pm to about 100 pm, or about 90 pm to about 100 pm.

[0054] The third plurality of particles generally may be present in a composite material at any amount. The amount may be selected based on the concentration of thefirst plurality of particles in the composite material. For example, in some embodiments, the first plurality7of particles and the third plurality of particles are present in the composite material at a weight ratio of about 0.5: 1 to about 2: 1, about 0.5:1 to about 1.6: 1, about 0.5: 1 to about 1.5: 1, about 0.8: 1 to about 1.5: 1, about 1: 1 to about 1.5: 1, about 1.1 : 1 to about 1.5: 1, or about 1.2: 1 to about 1.5: 1 (first plurality of particles : third plurality of particles).

[0055] In some embodiments, the third plurality7of particles is present in the composite material at an amount of about 5 wt% to about 50 wt%. about 5 wt% to about 40 wt%. about 5 wt% to about 30 wt%. about 10 wt% to about 30 wt%, about 15 wt% to about 25 wt%, about 18 wt% to about 22 wt%, or about 20 wt%, based on the weight of the composite material.

[0056] In some embodiments, the solid, e.g., polymer, used to form the third plurality of particles is present in the composite material at an amount of about 5 wt% to about 50 wt%, about 5 wt% to about 40 wt%, about 5 wt% to about 30 wt%, about 10 wt% to about 30 wt%, about 15 wt% to about 25 wt%, about 18 wt% to about 22 wt%, about 18 wt% to about 20 wt%, about 18 wt%, or about 20 wt%, based on the weight of the composite material. In some embodiments, the first plurality of particles and the solid, e.g., polymer, used to form the third plurality of particles are present in the composite material at a weight ratio of about 0.5: 1 to about 2: 1, about 0.5: 1 to about 1.6: 1, about 0.5: 1 to about 1.5: 1, about 0.8: 1 to about 1.5:1, about 1: 1 to about 1.5:1, about 1.1: 1 to about 1.5: 1, or about 1.2: 1 to about 1.5: 1 (first plurality of particles : solid, e.g., polymer, used to form third plurality of particles).Adhesive

[0057] The adhesive generally may include any known adhesive, including adhesives that are capable of effectively adhering to surfaces of any of the particles of the composite materials, especially the second plurality of particles. In some embodiments, the adhesive includes a surfactant. The adhesive may include a fatty acid, such as a saturated fatty acid. In some embodiments, the adhesive includes a compound of the following formula:H3C(CH2)nCOOH; wherein n is 10 to 30. 10 to 20, or 12 to 18.

[0058] In some embodiments, the adhesive includes stearic acid, myristic acid, lauric acid, or a combination thereof. In some embodiments, adhesive includesenanthic acid, caprylic acid, pelargonic acid, capric acid, undecylic acid, tridecyl acid, pentadecyl acid, nonadecanoic acid, arachidic acid, or behenic acid, acr lic acid, methacrylic acid, crotonic acid, isocrotonic acid, undecylenic acid, oleic acid, elaidic acid, cetoleic acid, brassidic acid, erucic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid, or a combination thereof.

[0059] In some embodiments, the adhesive includes a silicone oil. The silicone oil may have a viscosity that ensures or encourages wetting of particles, such as flake-shaped particles, and / or facilitates at least some adhesion of the silicone oil to particles, such as flake-shaped particles, through capillary force. The silicone oil may be a low-viscosity silicone oil. As used herein, the phrase “low-viscosity silicone oil” refers to a silicone oil having a viscosity at 25 °C that does not exceed 100 centistokes (cSt), 75 cSt, 50 cSt, 25 cSt, 10 cSt, or 5 cSt.

[0060] A composite material generally may include any amount of adhesive. The amount of adhesive that is present in a composite material may be determined, at least in part, by the surface area of the first plurality of particles and / or the second plurality of particles, which may be at least partially coated by the adhesive. In some embodiments, the adhesive is present in the composite material at a concentration of about 0. 1 wt% to about 20 wt%, about 0.5 wt% to about 15 wt%, about 5 wt% to about 15 wt%, or about 8 wt% to about 12 wt%, based on the weight of the composite material.

[0061] The composite materials provided herein also may include a liquid, such as the liquid used in the methods to prepare the third plurality of particles. The liquid may include a liquid in which the adhesive is at least partially soluble (i.e., a solubility of at least 0.1 g of adhesive per 100 mL of the liquid) or soluble (i.e., a solubility of at least 1 g of adhesive per 100 mL of the liquid). The liquid may include an organic liquid, such as a C5-C12 organic liquid. The liquid may include hexane.

[0062] The liquid may be present in a composite material at any amount. An amount of liquid in a composite material may decrease over time for one or more reasons, such as the volatility of the liquid, the temperature at which the composite material is stored and / or used, etc.

[0063] In some embodiments, the liquid is present in the composite material at an initial amount of about 0. 1 wt% to about 15 wt%, about 1 wt% to about 15 wt%, about 1 wt% to about 10 wt%, about 1 wt% to about 5 wt%, or about 1 wt% to about 3 wt%, based on the weight of the composite material. The “initial amount” of liquid that is present inthe composite material is the amount that is present in a newly-produced composite material (i.e., within one hour of production and before the composite material is exposed to a temperature of at least 100 °C).

[0064] The amount of liquid in a composite material may decrease after production for one or more reasons, such as the volatility of the liquid, the conditions in which a composite material is used and / or stored, etc. For example, when a composite material is exposed to a temperature of 125 °C for 48 hours, an amount of liquid in the composite material, such as the initial amount, may decrease by at least 1, at least 3, or at least 5 weight percentage points.Matrix Material

[0065] The matrix material generally may include any matrix material, such as any matrix material that is capable of withstanding the conditions at which a composite material may be used, and / or preserving, to a desired extent, an interconnected network of particles, as described herein.

[0066] The matrix material may be a thixotropic matrix material. The thixotropic matrix material may resist flow, or not flow, under one or more operating conditions of objects with which the compositions herein are used, and / or to which the compositions herein are applied. The thixotropic matrix material, however, may flow, to a desired extent, under manufacturing or other processing conditions, thereby facilitating application of the compositions herein to an object, a gap between objects, etc. In some embodiments, the matrix material is stable (e.g.. chemically stable) at temperatures less than 100 °C. less than 90 °C, less than 80 °C. less than 70 °C, or less than 60 °C.

[0067] In some embodiments, the matrix material includes a hydrocarbon, such as a polymeric hydrocarbon. In some embodiments, the matrix material is a lithium-based hydrocarbon. In some embodiments, the matrix material includes a paraffinic material. In some embodiments, the matrix material includes a silicon-based polymer, such as a polysiloxane (e.g., poly dimethylsiloxane (PDMS), polymethylhydrogensiloxane (PMHS), polydiethylsiloxane (PDES), polyphenylmethylsiloxane (PMPS), poly diphenylsiloxane (PDPS) etc.), which may be a component of a silicone grease. Therefore, the matrix material may include a silicone grease.

[0068] In some embodiments, the matrix material is present in the composite material at an amount of about 10 wt% to about 98 wt%, about 10 wt% to about 90 wt%, about 20 wt% to about 80 wt%, about 30 wt% to about 70 wt%, about 40 wt% to about 60wt%, about 45 wt% to about 55 wt%, about 50 wt% to about 60 wt%, or about 50 \\t% to about 55 wt%, based on the weight of the composite material.

[0069] All referenced publications are incorporated herein by reference in their entirety. Furthermore, where a definition or use of a term in a reference, which is incorporated by reference herein, is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.

[0070] While certain aspects of conventional technologies have been discussed to facilitate disclosure of various embodiments, applicants in no way disclaim these technical aspects, and it is contemplated that the present disclosure may encompass one or more of the conventional technical aspects discussed herein.

[0071] The present disclosure may address one or more of the problems and deficiencies of known methods and processes. However, it is contemplated that various embodiments may prove useful in addressing other problems and deficiencies in a number of technical areas. Therefore, the present disclosure should not necessarily be construed as limited to addressing any of the particular problems or deficiencies discussed herein.

[0072] In this specification, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date, publicly available, know n to the public, part of common general knowledge, or otherwise constitutes prior art under the applicable statutory' provisions; or is known to be relevant to an attempt to solve any problem with which this specification is concerned.

[0073] In the descriptions provided herein, the terms “includes,” “is,” “containing,” “having,” and “comprises” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to.” When composite materials or methods are claimed or described in terms of “comprising” various components or steps, the composite materials or methods can also “consist essentially of” or “consist of’ the various components or steps, unless stated otherwise.

[0074] The terms “a,” “an,” and “the” are intended to include plural alternatives, e.g. , at least one. For instance, the disclosure of “a gel”, “a liquid”, “a polymer”, and the like, is meant to encompass one, or mixtures or combinations of more than one gel, liquid, polymer, and the like, unless otherwise specified.

[0075] Various numerical ranges may be disclosed herein. When Applicant discloses or claims a range of any type. Applicant’s intent is to disclose or claim individually each possible number that such a range could reasonably encompass, including end points of the range as well as any sub-ranges and combinations of subranges encompassed therein, unless otherwise specified. Moreover, all numerical end points of ranges disclosed herein are approximate. As a representative example, Applicant discloses, in some embodiments, that the matrix material is present in the composite material at an amount of about 50 wt% to about 60 wt%. This range should be interpreted as encompassing about 50 wt% and about 60 wt%, and further encompasses "about ’ each of 51 wt%, 52 wt%, 53 wt%, 54 wt%, 55 wt%, 56 wt% 57 wt%, 58 wt%, and 59 wt%, including any ranges and sub-ranges between any of these values.

[0076] As used herein, the term “about” means plus or minus 10 % of the numerical value of the number with which it is being used.EXAMPLES

[0077] The present invention is further illustrated by the following examples, which are not to be construed in any way as imposing limitations upon the scope thereof. On the contrary, it is to be clearly understood that resort may be had to various other aspects, embodiments, modifications, and equivalents thereof which, after reading the description herein, may suggest themselves to one of ordinary skill in the art without departing from the spirit of the present invention or the scope of the appended claims. Thus, other aspects of this invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein.Example 1 - Preparation and Testing of Composite Material

[0078] In this example, an embodiment of a composite material was prepared.

[0079] Particles of a gel were first prepared by mixing styrene-ethylene / butylene- styrene particles and hexane. The mixing was allowed to continue for a time effective to form the gel particles, and after the gel particles were formed, a portion of the liquid was removed from the gel particles in some tests. The amount of liquid, in some instances, was selected to improve the results of subsequent processing.

[0080] The gel particles then were contacted with aluminum flakes, which, upon contact, adhered to surfaces of the gel particles (see, e.g., FIG. 1). Various weight ratios of gel particles to aluminum flakes were tested, including those shown in the following tables. Not wishing to be bound by any particular theory’, it was believed that the gelparticles, after the application of the aluminum flakes, acted as heat transfer units within the matrix phase of the composite materials produced according to this example. The gel particles and the aluminum flakes were mixed with a rotary mixer at relatively low speeds and short times, such as a speed not exceeding 50 rpm for a time not exceeding 5 minutes.

[0081] The gel particles to which the aluminum flakes were adhered, or a portion thereof, were then connected by contacting the gel particles / aluminum flakes and rod particles. The mixing of the gel particles / aluminum flakes and rod particles was achieved with a rotary’ mixer at relatively low speeds and short times. The rod particles used in this example were prepared by chopping an aluminum wool to produce the rod particles. Prior to contacting the gel particles / aluminum flakes, the rod particles optionally were placed in a super-saturated solution of stearic acid in hexane in order to coat the rod particles with an adhesive.

[0082] The resulting interconnected network of the gel particles / aluminum flakes and rod particles were then contacted with a matrix material, which, in this example, was a lithium paraffinic material. The gel particles / aluminum flakes, rod particles, and matrix material were mixed with a rotary mixer, typically at speeds not exceeding 60 rpm and a time not exceeding 30 minutes.

[0083] The components were added in amounts that resulted in an embodiment of a composite material having the following characteristics:Table 1. Characteristics of Tested Embodiment of a Composite Material

[0084] For comparison purposes, a reference composite material was prepared that included aluminum flakes and aluminum rods, but not the SEBS / hexane gel particles. The reference composite material had the following characteristics:Table 2. Characteristics of Comparative Example of a Composite Material

[0085] The aluminum flakes and aluminum rods were present in the reference composite material and the composite material of Table 2 at identical concentrations, but the aluminum flakes of the reference composite material were not adhered to — or in contact with — gel particles. The reference composite material was prepared in the same manner as the composite material of this example, except aluminum flakes were added to a gel-free liquid as the initial step.

[0086] The thermal conductivities of the reference composite material (Table 2, FIG. 2A) and the embodiment of the composite material (Table 1, FIG. 2B) were measured in compliance with ASTM D5470-17. FIG. 2A and FIG. 2B depicts the temperature responses of the materials, and the following table provides tabulated results of the measured thermal impedance and the thermal conductivity derived from the steadystate temperature response:Table 3. Thermal Conductivity of Tested Embodiment of Composite Material

[0087] The reference composite material had a thermal conductivity of 2.0 ± 0. 1 W / mk, and the embodiment of the composite material had a thermal conductivity of 2.3 ± 0. 1 W / mk. Therefore, the thermal conductivity of the tested embodiment of the composite material was about 15 % greater than the thermal conductivity of the reference composite material.EMBODIMENTS

[0088] The following is anon-limiting listing of embodiments of the disclosure.Composite Materials

[0089] Embodiment 1. A composite material comprising, consisting essentially of, or consisting of a matrix material, a first plurality of particles, a second plurality of particles, and a third plurality of particles.

[0090] Embodiment 2. The composite material of any of the preceding Embodiments, wherein a shape of the first plurality of particles differs from a shape of the second plurality of particles.

[0091] Embodiment 3. The composite material of any of the preceding Embodiments, wherein the first plurality of particles, the second plurality of particles, and the third plurality of particles are dispersed, evenly or unevenly, in the matrix material.

[0092] Embodiment 4. The composite material of any of the preceding Embodiments, wherein the first plurality of particles, the second plurality of particles, the third plurality of particles, or a combination thereof provide pathways (e.g., conductive pathways, such as thermally conductive pathways) in the composite material, due, for example, at least in part to points of physical contact between (i) at least a portion of the first plurality7of particles and at least a portion of the third plurality7of particles, (ii) at least a portion of the first plurality of particles and at least a portion of the second plurality of particles, or (iii) a combination thereof. (The third plurality of particles may not include a thermally conductive material, and, in such instances, the contribution of the third plurality of particles includes facilitating a beneficial relationship between the first plurality7of particles and the third plurality of particles, as described herein.)

[0093] Embodiment 5. The composite material of any of the preceding Embodiments, wherein at least a portion of the first plurality of particles, at least a portion of the second plurality of particles, at least a portion of the third plurality of particles, or a combination thereof form an interconnected network in the composite material due to points of physical contact between (i) at least a portion of the first plurality of particles and at least a portion of the third plurality of particles, (ii) at least a portion of the first plurality of particles and at least a portion of the second plurality of particles, or (iii) a combination thereof.

[0094] Embodiment 6. The composite material of any of the preceding Embodiments, further comprising, further consisting essentially of, or further consisting of an adhesive; wherein, optionally, (i) the first plurality of particles is at least partially coated with the adhesive, (ii) the second plurality of particles is at least partially coatedwith the adhesive, or (iii) the first plurality of particles and the second plurality of particles are at least partially coated with the adhesive.

[0095] Embodiment 7. The composite material of any of the preceding Embodiments, wherein the shape of the second plurality of particles is effective to reduce the Gibbs energy barrier for nucleation (e.g., heterogeneous nucleation) of the adhesive from a liquid (e.g., a solution of the adhesive) (e.g., a liquid used to form the third plurality of particles, as described herein) to surfaces of the second plurality of particles, which may result in a substantially uniform deposition of the adhesive on the surfaces.

[0096] Embodiment 8. The composite material of any of the preceding Embodiments, wherein the composite material is a paste.Methods of Forming Composite Materials

[0097] Embodiment 9. A method of forming a composite material, the method comprising, consisting essentially of. or consisting of -

[0098] (A) (i) providing a first plurality’ of particles; (ii) providing a second plurality’ of particles; (iii) providing a third plurality of particles; (iv) contacting the first plurality of particles and the third plurality of particles; (v) contacting the second plurality of particles, the first plurality of particles, and the third plurality of particles; and (vi) contacting a matrix material, the first plurality of particles, the second plurality of particles, and the third plurality of particles to form the composite material; or

[0099] (B) (i) providing a first plurality of particles; (ii) providing a second plurality of particles; (iii) providing a third plurality of particles; (iv) contacting the first plurality of particles and the third plurality of particles to form a first intermediate material; (v) contacting the second plurality of particles and the first intermediate material to form a second intermediate material; and (vi) contacting a matrix material and the second intermediate material to form the composite material.

[0100] Embodiment 10. The method of any of the preceding Embodiments, wherein the providing of the third plurality of particles comprises, consists essentially of, or consists of - (i) contacting a liquid and a plurality of particles of a solid (e.g., a polymer), and (ii) mixing the plurality of particles of the solid and the liquid for a time effective to form the third plurality of particles; wherein, optionally, any one or more of elements (iv). (v). or (vi) of Embodiment 9 occurs in the presence of the liquid; and wherein, optionally, the method further comprises, further consists essentially of, orconsists of separating at least a portion of the liquid from the third plurality of particles, or reducing and / or increasing a volume of the liquid.

[0101] Embodiment 11. The method of any of the preceding Embodiments, wherein the mixing of the plurality of particles of the solid (e.g.. polymer) and the liquid occurs for a time of about 1 minutes to about 30 minutes, about 1 minutes to about 20 minutes, or about 5 minutes to about 10 minutes.

[0102] Embodiment 12. The method of any of the preceding Embodiments, further comprising, further consisting essentially of, or further consisting of disposing an adhesive in the liquid, and optionally mixing the liquid and the adhesive.

[0103] Embodiment 13. The method of any of the preceding Embodiments, wherein when the adhesive is soluble in the liquid, and the adhesive and the liquid are optionally mixed for a time effective to dissolve, completely or partially, the adhesive in the liquid, such as a time of about 5 to about 20 minutes, or about 10 minutes to about 15 minutes.

[0104] Embodiment 14. The method of any of the preceding Embodiments, further comprising, consisting essentially of, or consisting of separating a portion of the liquid from the third plurality of particles (such as via filtration, evaporation, or otherwise) before (i) the contacting of the first and third pluralities of particles, (ii) the contacting of the first, second, and third pluralities of particles (or the contacting of the second plurality of particles and the first intermediate material), (iii) the contacting of the matrix material and the first, second, and third pluralities of particles (or contacting of the matrix material and the second intermediate material), or (iv) a combination thereof.

[0105] Embodiment 15. The method of any of the preceding Embodiments, wherein (i) the contacting of the first plurality of particles and the third plurality of particles (and, optionally, the adhesive), (ii) the contacting of the first plurality of particles, the second plurality of particles, and the third plurality of particles (and. optionally, the adhesive) (or the contacting of the second plurality of particles and the first intermediate material), (iii) the contacting of the of the first plurality of particles, the second plurality’ of particles, the third plurality’ of particles, and the matrix material (and, optionally, the adhesive) (or the contacting of the matrix material and the second intermediate material), or (iv) a combination thereof comprises, consists essentially of, or consists of mixing, e.g., stirring, such as with a dynamic mixer, for example, a rotary mixer.

[0106] Embodiment 16. The method of any of the preceding Embodiments, wherein the mixing of the first plurality of particles, the second plurality of particles, and / or the third plurality of particles imparts a force to the first plurality of particles, the second plurality of particles, and / or the third plurality of particles that does not undesirably reduce and / or alter (A) the points of contact between (i) at least a portion of the first plurality of particles and at least a portion of the third plurality of particles, and / or (ii) at least a portion of the first plurality of particles and at least a portion of the second plurality of particles, or (B) the interconnected network formed by the at least a portion of the first plurality of particles, at least a portion of the second plurality of particles, and / or at least a portion of the third plurality’ of particles.

[0107] Embodiment 17. The method of any of the preceding Embodiments, wherein the mixing of the first plurality of particles, the second plurality of particles, the third plurality of particles, or a combination thereof comprises, consists essentially of or consists of stirring with a rotary mixer at about 5 rpm to about 50 rpm, about 10 rpm to about 50 rpm, about 20 rpm to about 50 rpm, about 30 rpm to about 50 rpm, about 40 rpm to about 50 rpm, about 5 rpm to about 40 rpm, about 5 rpm to about 30 rpm. about 5 rpm to about 20 rpm, or about 5 rpm to about 10 rpm.

[0108] Embodiment 18. The method of any of the preceding Embodiments, wherein the mixing of the first plurality’ of particles, the second plurality’ of particles, the third plurality’ of particles, or a combination thereof occurs for about 30 seconds to about 5 minutes, about 1 minute to about 5 minutes, about 2 minutes to about 5 minutes, about 3 minutes to about 5 minutes, about 4 minutes to about 5 minutes, about 30 seconds to about 4 minutes, about 30 seconds to about 3 minutes, about 30 seconds to about 2 minutes, or about 30 seconds to about 1 minute.

[0109] Embodiment 19. The method of any of the preceding Embodiments, wherein the mixing of the matrix material, the first plurality of particles, the second plurality of particles, the third plurality of particles, or a combination thereof comprises, consists essentially of, or consists of stirring, such as with a dynamic mixer, for example, a rotary mixer.

[0110] Embodiment 20. The method of any of the preceding Embodiments, wherein the mixing of the matrix material, the first plurality of particles, the second plurality’ of particles, and the third plurality' of particles, imparts a force to the first plurality of particles, the second plurality of particles, and the third plurality’ of particlesthat does not undesirably reduce and / or alter (A) the points of contact between (i) at least a portion of the first plurality of particles and at least a portion of the third plurality of particles, and / or (ii) at least a portion of the first plurality of particles and at least a portion of the second plurality of particles, or (B) the interconnected network formed by the at least a portion of the first plurality of particles, at least a portion of the second plurality of particles, and / or at least a portion of the third plurality of particles.[OHl] Embodiment 21. The method of any of the preceding Embodiments, wherein the mixing of the matrix material, the first plurality of particles, the second plurality of particles, and the third plurality of particles comprises, consists essentially of. or consists of stirring with a rotary mixer at about 5 rpm to about 60 rprn, about 10 rpm to about 60 rpm, about 20 rpm to about 60 rpm, about 30 rpm to about 60 rpm, about 40 rpm to about 60 rpm, about 50 rpm to about 60 rpm, about 5 rpm to about 60 rpm, about 5 rpm to about 50 rpm, about 5 rpm to about 40 rpm, about 5 rpm to about 30 rpm, about 5 rpm to about 20 rpm, or about 5 rpm to about 10 rpm.

[0112] Embodiment 22. The method of any of the preceding Embodiments, wherein the mixing of the matrix material, the first plurality of particles, the second plurality of particles, and the third plurality of particles, occurs for about 10 minutes to about 30 minutes, about 10 minutes to about 25 minutes, about 10 minutes to about 20 minutes, about 10 minutes to about 15 minutes, about 15 minutes to about 30 minutes, about 20 minutes to about 30 minutes, or about 25 minutes to about 30 minutes.Methods of Using Composite Materials

[0113] Embodiment 23. A method of improving heat transfer, the method comprising, consisting essentially of, or consisting of - (i) providing a composite material of any of the preceding Embodiments; (ii) arranging the composite material between and in contact with a surface of a first object and a surface of a second object.

[0114] Embodiment 24. The method of Embodiment 23, wherein the surface of the first object and the surface of the second object are at different temperatures prior to the arranging of the composite material.

[0115] Embodiment 25. The method of Embodiment 24, wherein a temperature difference between the different temperatures of the surface of the first object and the surface of the second object is at least 5 °C, at least 10 °C. at least 20 °C, at least 30 °C. at least 40 °C, or at least 50 °C.

[0116] Embodiment 26. The method of any of the preceding Embodiments, wherein the first object is a pipe, channel, other heat exchanger component, or a condenser in a refrigeration circuit, such as for a heat pump water heater; for example, the first object may be a microchannel condenser in the refrigeration circuit.

[0117] Embodiment 27. The method of any of the preceding Embodiments, wherein the second object is a tank; for example, the tank may be a hot water tank arranged for heat exchange with the first object (e.g., a microchannel condenser of a heat pump water heater). irst Plurality) of Particles

[0118] Embodiment 28. The composite material or method of any of the preceding Embodiments, wherein the first plurality of particles comprises, consists essentially of, or consists of flake-shaped particles.

[0119] Embodiment 29. The composite material or method of any of the preceding Embodiments, wherein the first plurality’ of particles comprises, consists essentially of, or consists of particles having different dimensions or one or more substantially uniform dimensions (e.g., thicknesses (or other dimensions) within ± 5 % of each other).

[0120] Embodiment 30. The composite material or method of any of the preceding Embodiments, wherein each particle of the first plurality of particles has a first surface, a second surface opposite the first surface, and a thickness.

[0121] Embodiment 31. The composite material or method of Embodiment 30, wherein the first plurality of particles has an average thickness of about 1 pm to about 200 pm, about 10 pm to about 200 pm, about 10 pm to about 150 pm, about 10 pm to about 100 pm, about 10 pm to about 50 pm, about 50 pm to about 200 pm, about 100 pm to about 200 pm, or about 150 pm to about 200 pm.

[0122] Embodiment 32. The composite material or method of Embodiment 30 or 31, wherein the first plurality of particles has an average largest dimension of the first surface of about 1 pm to about 200 pm, about 10 pm to about 200 pm, about 10 pm to about 150 pm, about 10 pm to about 100 pm, about 10 pm to about 50 pm, about 50 pm to about 200 pm, about 100 pm to about 200 pm, or about 150 pm to about 200 pm.

[0123] Embodiment 33. The composite material or method of any one of Embodiments 30 to 32, wherein a ratio of the average largest dimension of the first surface to the thickness is about 100: 1 to about 1: 1, about 50: 1 to about 1:1, about 40: 1 to about1 : 1 , about 30: 1 to about 1 : 1 , about 20: 1 to about 1 : 1, about 10:1 to about 1 : 1 , about 100: 1 to about 2: 1, about 50: 1 to about 2: 1, about 40:1 to about 2: 1, about 30: 1 to about 2:1, about 20: 1 to about 2:1, or about 10: 1 to about 2:1 (largest dimension of the first surface : thickness).

[0124] Embodiment 34. The composite material or method of any of the preceding Embodiments, wherein the first pl urality of particles is formed at least in part of a first metal.

[0125] Embodiment 35. The composite material or method of any of the preceding Embodiments, wherein the first metal is aluminum, silver, or a combination thereof.

[0126] Embodiment 36. The composite material or method of any of the preceding Embodiments, wherein the first plurality of particles is formed at least in part of a first ceramic.

[0127] Embodiment 37. The composite material or method of any of the preceding Embodiments, wherein the first ceramic comprises alumina, aluminum nitride, zinc oxide, silicon carbide, silicon nitrides, and beryllium oxides.

[0128] Embodiment 38. The composite material or method of any of the preceding Embodiments, wherein the first plurality of particles is formed at least in part of graphene, carbon nanotubes (e.g., a buckypaper, a nanoribbon, etc.), or a combination thereof.

[0129] Embodiment 39. The composite material or method of any of the preceding Embodiments, wherein the first plurality of particles is present in the composite material at an amount of about 0. 1 wt% to about 50 wt%, about 5 wt% to about 45 wt%, about 10 \vt% to about 40 wt%, about 20 wt% to about 40 wt%, about 20 wt% to about 30 wt%, about 20 wt% to about 25 wt%, about 23 v % to about 25 wt%, about 25 wt% to about 35 wt%, or about 25 wt% to about 30 wt%, based on the weight of the composite material.Second Plurality of Particles

[0130] Embodiment 40. The composite material or method of any of the preceding Embodiments, wherein the shape of the second plurality of particles comprises, consists essentially of, or consists of rod-shaped particles.

[0131] Embodiment 41 . The composite material or method of any of the preceding Embodiments, wherein the second plurality of particles comprises, consistsessentially of, or consists of particles having different dimensions or one or more substantially uniform dimensions (e.g., lengths within ± 5 % of each other).

[0132] Embodiment 42. The composite material or method of any of the preceding Embodiments, wherein each particle of the second plurality of particles has a length (or height) and a width (or diameter when the rod-shaped particles are cylindrical).

[0133] Embodiment 43. The composite material or method of Embodiment 42, wherein the second plurality7of particles has an average width (or diameter) of about 1 pm to about 400 pm, about 40 pm to about 400 pm, about 1 pm to about 300 pm, about 40 pm to about 300 pm, about 1 pm to about 200 pm. about 40 pm to about 200 pm. about 1 pm to about 100 pm, about 40 pm to about 100 pm, about 100 pm to about 400 pm, about 200 pm to about 400 pm, or about 300 pm to about 400 pm.

[0134] Embodiment 44. The composite material or method of Embodiment 42 or 43, wherein the second plurality of particles has an average length (or height) of about 1 pm to about 2,000 pm, about 1 pm to about 1,500 pm, about 1 pm to about 1,000 pm, about 1 pm to about 500 pm, about 10 pm to about 500 pm, about 10 pm to about 400 pm, about 10 pm to about 300 pm, about 10 pm to about 200 pm, about 10 pm to about 100 pm. about 10 pm to about 50 pm, about 50 pm to about 500 pm, about 100 pm to about 500 pm, about 200 pm to about 500 pm, about 300 pm to about 500 pm, or about 400 pm to about 500 pm.

[0135] Embodiment 45. The composite material or method of any one of Embodiments 42 to 44, wherein a ratio of the average length (or height) to the average width (or diameter) is about 50: 1 to about 1 : 1, about 40: 1 to about 1 : 1, about 30: 1 to about 1 : 1 , about 20: 1 to about 1 : 1, about 10: 1 to about 1 : 1, about 5: 1 to about 1 : 1, about 50: 1 to about 2:1, about 40:1 to about 2: 1, about 30: 1 to about 2: 1, about 20: 1 to about 2: 1, about 10: 1 to about 2: 1, about 5: 1 to about 2: 1, about 50:1 to about 5: 1, about 40: 1 to about 5:1, about 30: 1 to about 5: 1. about 20: 1 to about 5: 1, about 12: 1 to about 5: 1, or about 10: 1 to about 5: 1 (average length (or height) : average width (or diameter)).

[0136] Embodiment 46. The composite material or method of any of the preceding Embodiments, wherein the second plurality of particles is formed at least in part of a second metal.

[0137] Embodiment 47. The composite material or method of any of the preceding Embodiments, w h erein the first metal and the second metal are the same or different.

[0138] Embodiment 48. The composite material or method of any of the preceding Embodiments, wherein the second metal is aluminum, silver, or a combination thereof.

[0139] Embodiment 49. The composite material or method of any of the preceding Embodiments, wherein the second plurality of particles comprises, consists essentially of, or consists of a wool, such as a metal wool (e.g., aluminum wool), that has been processed to reduce the dimensions of the wool, particularly the lengths of each strand of the wool.

[0140] Embodiment 50. The composite material or method of any of the preceding Embodiments, wherein the second plurality of particles is formed at least in part of a second ceramic.

[0141] Embodiment 51. The composite material or method of any of the preceding Embodiments, wherein the first ceramic or the second ceramic are the same or different.

[0142] Embodiment 52. The composite material or method of any of the preceding Embodiments, wherein the second ceramic comprises alumina, aluminum nitride, zinc oxide, silicon carbide, silicon nitrides, beryllium oxides, or a combination thereof.

[0143] Embodiment 53. The composite material or method of any of the preceding Embodiments, wherein the second plurality of particles is formed at least in part of graphene, carbon nanotubes, or a combination thereof.

[0144] Embodiment 54. The composite material or method of any of the preceding Embodiments, wherein the second plurality of particles is present in the composite material at an amount of about 0.001 wt% to about 30 wt%, about 0. 1 wt% to about 25 wt %, about 0.1 wt% to about 20 wt%, about 0.1 wt% to about 15 vvt%, about 0.1 wt% to about 10 wt%, about 1 wt% to about 10 wt%, about 2 wt% to about 8 wt%, about 4 wt% to about 6 wt%, or about 5 wt%, based on the weight of the composite material.

[0145] Embodiment 55. The composite material or method of any of the preceding Embodiments, wherein a ratio of the concentrations (wt%) of the first plurality7of particles to the second plurality of particles in the composite material is about 2: 1 to about 10: 1, about 2: 1 to about 8: 1, about 4: 1 to about 8: 1, about 4: 1 to about 7: 1, about 4: 1 to about 6: 1 , or about 5: 1 to about 6: 1 (first plurality of particles (wt%) : second plurality of particles (wt%)).Third Plurality of Particles

[0146] Embodiment 56. The composite material or method of any of the preceding Embodiments, wherein the gel of the third plurality of particles is derived from a solid, e.g.. a polymer, and a liquid; therefore, the first plurality of particles, in some instances, may adhere to the third plurality of particles, due, for example, to capillary action of a liquid of the gel.

[0147] Embodiment 57. The composite material or method of any of the preceding Embodiments, wherein the polymer comprises, consists essentially of, or consists of a crosslinked polymer.

[0148] Embodiment 58. The composite material or method of any of the preceding Embodiments, wherein the polymer comprises, consists essentially of, or consists of a homopolymer, a copolymer (e.g., a terpolymer, block copolymer, etc.), or a combination thereof.

[0149] Embodiment 59. The composite material or method of any of the preceding Embodiments, wherein the polymer comprises, consists essentially of, or consists of repeat units derived from an alkene monomer (e.g., a C2-C6 alkene monomer), a styrene monomer, or a combination thereof.

[0150] Embodiment 60. The composite material or method of any of the preceding Embodiments, wherein the polymer comprises a styrene-ethylene / butylene- styrene (SEBS) copolymer.

[0151] Embodiment 61. The composite material or method of any of the preceding Embodiments, wherein the liquid comprises, consists essentially of, or consists of an organic liquid.

[0152] Embodiment 62. The composite material or method of Embodiment 61, wherein the organic liquid comprises, consists essentially of. or consists of an alkane (e.g., a C3-C10 alkane).

[0153] Embodiment 63. The composite material or method of Embodiment 62, wherein the organic liquid comprises, consists essentially of, or consists of hexane.

[0154] Embodiment 64. The composite material or method of any of the preceding Embodiments, wherein (A) the third plurality of particles is present in the composite matenal at an amount of about 5 wt% to about 50 wt%, about 5 wt% to about 40 wt%, about 5 wt% to about 30 wt%, about 10 wt% to about 30 wt%, about 15 wt% to about 25 wt%, about 18 wt% to about 22 wt%, or about 20 wt%, based on the weight ofthe composite material, and / or (B) the solid, e g., polymer, used to form the third plurality of particles is present in the composite material at an amount of about 5 wt% to about 50 wt%, about 5 wt% to about 40 wt%, about 5 wt% to about 30 wt%, about 10 wt% to about 30 wt%. about 15 wt% to about 25 wt%, about 18 wt% to about 22 wt%, about 18 wt% to about 20 wt%, about 18 wt%, or about 20 wt%, based on the weight of the composite material.

[0155] Embodiment 65. The composite material or method of any of the preceding Embodiments, wherein the third plurality of particles has an average largest dimension of about 1 pm to about 1,000 pm. about 1 pm to about 800 pm, about 1 pm to about 600 pm, about 1 pm to about 500 pm, about 10 pm to about 500 pm, about 20 pm to about 500 pm, about 30 pm to about 500 pm, about 40 pm to about 500 pm, about 50 pm to about 500 pm, about 100 pm to about 500 pm, about 200 pm to about 500 pm. about 300 pm to about 500 pm, about 400 pm to about 500 pm, about 50 pm to about 400 pm, about 50 pm to about 300 pm, about 50 pm to about 200 pm, about 50 pm to about 100 pm, about 1 pm to about 200 pm, about 1 pm to about 100 pm, about 1 pm to about 90 pm, about 1 pm to about 80 pm, about 1 pm to about 70 pm, about 1 pm to about 60 pm, about 1 pm to about 50 pm, about 1 pm to about 40 pm, about 1 pm to about 30 pm. about 1 pm to about 20 pm, about 1 pm to about 10 pm, about 10 pm to about 100 pm, about 20 pm to about 100 pm, about 30 pm to about 100 pm, about 40 pm to about 100 pm, about 50 pm to about 100 pm, about 60 pm to about 100 pm, about 70 pm to about 100 pm. about 80 pm to about 100 pm, or about 90 pm to about 100 pm.

[0156] Embodiment 66. The composite material or method of any of the preceding Embodiments, wherein the polymer of the third plurality of particles — prior to swelling upon contacting the liquid — is in the form of particles, and has an average largest dimension of about 1 pm to about 1,000 pm, about 1 pm to about 800 pm, about 1 pm to about 600 pm, about 1 pm to about 400 pm, about 1 pm to about 200 pm. about 1 pm to about 100 pm, about 1 pm to about 90 pm, about 1 pm to about 80 pm, about 1 pm to about 70 pm, about 1 pm to about 60 pm, about 1 pm to about 50 pm, about 1 pm to about 40 pm, about 1 pm to about 30 pm, about 1 pm to about 20 pm, about 1 pm to about 10 pm, about 10 pm to about 100 pm, about 20 pm to about 100 pm, about 30 pm to about 100 pm, about 40 pm to about 100 pm, about 50 pm to about 100 pm, about 60 pm to about 100 pm, about 70 pm to about 100 pm, about 80 pm to about 100 pm, or about 90 pm to about 100 pm.

[0157] Embodiment 67. The composite material or method of any of the preceding Embodiments, wherein the first plurality of particles and the third plurality of particles are present in the composite material at a weight ratio of about 0.5:1 to about 2: 1, about 0.5: 1 to about 1.6: 1, about 0.5: 1 to about 1.5: 1, about 0.8: 1 to about 1.5: 1, about 1: 1 to about 1.5: 1, about 1.1: 1 to about 1.5: 1, or about 1.2: 1 to about 1.5: 1 (first plurality of particles : third plurality of particles); or wherein the first plurality of particles and the solid (e.g., polymer) of the third plurality of particles is present in the composite material at a weight ratio of about 0.5: 1 to about 2: 1, about 0.5: 1 to about 1.6: 1, about 0.5: 1 to about 1.5: 1. about 0.8: 1 to about 1.5: 1. about 1: 1 to about 1.5: 1. about 1.1 : 1 to about 1.5: 1, or about 1.2: 1 to about 1.5: 1 (first plurality of particles : solid (e g., polymer) of the third plurality' of particles).Adhesive

[0158] Embodiment 68. The composite material or method of any of the preceding Embodiments, wherein the adhesive comprises, consists essentially of, or consists of a surfactant.

[0159] Embodiment 69. The composite material or method of any of the preceding Embodiments, wherein the adhesive comprises, consists essentially of, or consists of a fatty acid.

[0160] Embodiment 70. The composite material or method of any of the preceding Embodiments, wherein the adhesive comprises, consists essentially of, or consists of a saturated fatty acid.

[0161] Embodiment 71. The composite material or method of any of the preceding Embodiments, wherein the adhesive comprises, consists essentially of, or consists of a compound of the following formula:H3C(CH2)nCOOH; wherein n is 10 to 30, 10 to 20, or 12 to 18.

[0162] Embodiment 72. The composite material or method of any of the preceding Embodiments, wherein the adhesive comprises, consists essentially of, or consists of stearic acid, myristic acid, lauric acid, or a combination thereof.

[0163] Embodiment 73. The composite material or method of any of the preceding Embodiments, wherein the adhesive comprises, consists essentially of, or consists of enanthic acid, caprylic acid, pelargonic acid, capric acid, undecylic acid, tridecyl acid, pentadecyl acid, nonadecanoic acid, arachidic acid, or behenic acid,acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, undecylenic acid, oleic acid, elaidic acid, cetoleic acid, brassidic acid, erucic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid, or a combination thereorf.

[0164] Embodiment 74. The composite material or method of any of the preceding Embodiments, wherein the adhesive comprises, consists essentially of, or consists of a silicone oil, such as a low-viscosity silicone oil.

[0165] Embodiment 75. The composite material or method of any of the preceding Embodiments, wherein the adhesive is present in the composite material at a concentration of about 0. 1 wt% to about 20 wt%, about 0.5 wt% to about 15 wt%. about 5 wt% to about 15 wt%, or about 8 wt% to about 12 wt%, based on the weight of the composite material.Liquid

[0166] Embodiment 76. The composite material or method of any of the preceding Embodiments, wherein the composite material further comprises, consists essentially of, or consists of a liquid, such as the liquid from which the third plurality of particles may be derived by contacting the liquid and a solid (e.g., a polymer).

[0167] Embodiment 77. The composite material or method of any of the preceding Embodiments, wherein the liquid comprises, consists essentially of, or consists of an organic liquid.

[0168] Embodiment 78. The composite material or method of any of the preceding Embodiments, wherein the liquid comprises, consists essentially of, or consists of hexane.

[0169] Embodiment 79. The composite material or method of any of the preceding Embodiments, wherein the adhesive is soluble in the liquid.

[0170] Embodiment 80. The composite material or method of any of the preceding Embodiments, wherein the adhesive is completely or partially dissolved or soluble in the liquid.

[0171] Embodiment 81. The composite material or method of any of the preceding Embodiments, wherein the liquid is a super-saturated solution of the adhesive (i.e.. the adhesive is present in the liquid at an amount that exceeds the maximum amount of the adhesive that is soluble in the liquid at a temperature at which the method is performed).

[0172] Embodiment 82. The composite material or method of any of the preceding Embodiments, wherein the liquid is present in the composite material at an amount of about 0. 1 wt% to about 15 wt%, about 1 wt% to about 15 wt%, about 1 wt% to about 10 wt%, about 1 wt% to about 5 wt%, or about 1 wt% to about 3 wt%.Matrix Material

[0173] Embodiment 83. The composite material or method of any of the preceding Embodiments, wherein the matrix material comprises, consists essentially of, or consists of a hydrocarbon, a silicone, or a combination thereof.

[0174] Embodiment 84. The composite material or method of any of the preceding Embodiments, wherein the hydrocarbon is a polymeric hydrocarbon.

[0175] Embodiment 85. The composite material or method of any of the preceding Embodiments, wherein the matrix material comprises, consists essentially of. or consists of a lithium-based hydrocarbon, a paraffinic material, and / or a silicon-based polymer, which may be a component of a silicone grease.

[0176] Embodiment 86. The composite material or method of any of the preceding Embodiments, wherein the matrix material is present in the composite material at an amount of about 10 wt% to about 98 wt%, about 10 wt% to about 90 wt%. about 20 wt% to about 80 wt%, about 30 wt% to about 70 wt%, about 40 wt% to about 60 wt%, about 45 wt% to about 55 wt%, about 50 wt% to about 60 wt%, or about 50 wt% to about 55 wt%, based on the weight of the composite material.Relative Properties

[0177] Embodiment 87. The composite material or method of any of the preceding Embodiments, wherein the composite material has a thermal conductivity (W / m'lK_|) that is at least 5 %, at least 10 %, at least 15 %, at least 20 %, at least 25 %, at least 30 %, at least 40 %, at least 50 %, or at least 60 % greater than a thermal conductivity (W / m^K1) of a comparative composite material that includes the first plurality of particles and the second plurality of particles but not the third plurality of particles (see, e.g., the reference composite material of Example 1), wherein the first plurality of particles and the second plurality of particles are present in the comparative composite material at concentrations that are within about 10 wt%, about 5 wt%. or about 1 wt% of the concentration of the first plurality of particles and the second plurality of particles, respectively, in the composite material. (For example, if a comparative composite material has a thermal conductivity of 10 units, and a composite material has a thermalconductivity of 16 units, then the composite material has athermal conductivity that is 60 % greater than the thermal conductivity of the comparative composite material.) (As a further example, if a comparative composite material includes about 25 wt% to about 35 wt% of the first plurality of particles, and about 0. 1 wt% to about 10 wt% of the second plurality of particles, and a composite material includes about 30 wt% of the first plurality of particles, about 5 wt% of the second plurality of particles, and about 20 wt% of the third plurality of particles, then the comparative composite material includes the first plurality of particles and the second plurality of particles at concentrations that are within about 5 wt% of the respective concentrations of the first plurality’ of particles and the second plurality' of particles in the composite material.)

[0178] Embodiment 88. The composite material or method of any of the preceding Embodiments, wherein the composite material has a thermal impedance (K nrW’1) that is at least 10 %, at least 15 %, at least 20 %, at least 25 %. at least 30 %, at least 40 %, at least 50 %, or at least 60 % less than a thermal impedance (K m2W-1) of a comparative composite material that includes the first plurality’ of particles and the second plurality of particles but not the third plurality of particles (see, e.g., the reference composite material of Example 1), wherein the first plurality of particles and the second plurality of particles are present in the comparative composite material at concentrations that are within about 10 wt%, about 5 wt%, or about 1 wt% of the concentration of the first plurality of particles and the second plurality of particles, respectively, in the composite material. (For example, if a comparative composite material has a thermal impedance of 10 units, and a composite material has a thermal impedance of 6 units, then the composite material has a thermal conductivity that is 40 % less than the thermal impedance of the comparative composite material.)Provisos

[0179] Embodiment 89. The composite material or method of any of the preceding Embodiments, wherein the composite material does not include graphene, or graphene is present at an amount not exceeding 10 wt%, 5 wt%, 1 wt%, or 0. 1 wt%, based on the weight of the composite material.

[0180] Embodiment 90. The composite material or method of any of the preceding Embodiments, wherein the composite material does not include carbon nanotubes (e g., single-walled, multi -walled, metal coated carbon nanotubes, or acombination thereof), or carbon nanotubes are present at an amount not exceeding 10 wt%, 5 wt%, 1 wt%, or 0.1 wt%, based on the weight of the composite material.

[0181] Embodiment 91. The composite material or method of any of the preceding Embodiments, wherein the composite material does not include carbon fibers, or carbon fibers are present at an amount not exceeding 10 wt%, 5 wt%, 1 wt%, or 0. 1 wt%, based on the weight of the composite material.

Claims

ClaimsThat which is claimed is:

1. A composite material comprising: a matrix material; a first plurality of particles, wherein the first plurality of particles comprises flake-shaped particles; a second plurality of particles, wherein the second plurality of particles comprises rod-shaped particles; and a third plurality of particles, wherein the third plurality of particles comprises a gel; wherein the first plurality of particles, the second plurality of particles, and the third plurality of particles are dispersed in the matrix material, and wherein the first plurality of particles, the second plurality of particles, and the third plurality of particles form an interconnected network in the composite material due to points of physical contact between (i) at least a portion of the first plurality of particles and at least a portion of the third plurality of particles, and (ii) the at least a portion of the first plurality of particles and at least a portion of the second plurality of particles.

2. The composite material of claim 1, wherein the composite material has a thermal conductivity' (W / m^K’1) that is at least 10 % greater than a thermal conductivity (W / nT1K"1) of a comparative composite material that includes the first plurality of particles and the second plurality of particles, but not the third plurality of particles; wherein the first plurality of particles is present in the comparative composite material at a concentration that is within about 10 wt% of the concentration of the first plurality of particles in the composite material; and wherein the second plurality of particles is present in the comparative composite material at a concentration that is within about 10 wt% of the concentration of the second plurality of particles in the composite material.

3. The composite material of claim 1, wherein each particle of the first plurality of particles has a first surface, a second surface opposite the first surface, and athickness, and wherein the first plurality of particles has an average thickness of about 1 pm to about 200 pm, and an average largest dimension of the first surface of about 1 pm to about 200 pm.

4. The composite material of claim 3, wherein a ratio of the average largest dimension of the first surface to the average thickness is about 20: 1 to about 2: 1 (average largest dimension of the first surface : average thickness).

5. The composite material of claim 1, wherein each particle of the second plurality of particles has a length and a width, and wherein the second plurality of particles has an average width about 1 pm to about 300 pm, and an average length of about 1 pm to about 2,000 pm.

6. The composite material of claim 5, wherein a ratio of the average length to the average width is about 12: 1 to about 5: 1 (average length : average width).

7. The composite material of claim 1, wherein the first plurality of particles is present in the composite material at an amount of about 10 wt% to about 40 wt %, and the second plurality of particles is present in the composite material is present in the composite material at an amount of about 1 wt% to about 15 wt%, based on the weight of the composite material.

8. The composite material of claim 1, wherein the gel is derived from a polymer and a liquid.

9. The composite material of claim 8, wherein the polymer comprises repeat units derived from an alkene monomer, a styrene monomer, or a combination thereof.

10. The composite material of claim 8, wherein the polymer comprises a styrene- ethylene / butylene-styrene (SEBS) copolymer.

11. The composite material of claim 8, wherein the liquid comprises an organic liquid.

12. The composite material of claim 1, wherein the gel of the third plurality of particles is derived from a polymer and a liquid, and the polymer is present in the composite material at a concentration of about 10 wt% to about 30 wt%, based on the weight of the composite material.

13. The composite material of claim 12, wherein at least a portion of the first plurality of particles adheres to at least a portion of the third plurality of particles due to capillary action of the liquid of the gel14. The composite material of claim 1, wherein the third plurality of particles has an average largest dimension of about 1 pm to about 1 ,000 pm.

15. The composite material of claim 1, further comprising an adhesive, wherein the first plurality of particles or the second plurality of particles is at least partially coated with the adhesive.

16. A method of forming a composite material, the method comprising: providing a first plurality of particles, wherein the first plurality of particles comprises flake-shaped particles; providing a second plurality of particles, wherein the second plurality of particles comprises rod-shaped particles; providing a third plurality of particles comprising a gel; contacting the first plurality of particles and the third plurality of particles to form a first intermediate material; contacting the second plurality of particles and the first intermediate material to form a second intermediate material; and contacting a matrix material and the second intermediate material to form the composite material.

17. The method of claim 16, wherein the providing of the third plurality of particles comprises:contacting a liquid and a plurality of particles of a polymer, and mixing the plurality of particles of the polymer and the liquid for a time effective to form the third plurality of particles.

18. The method of claim 16, wherein the contacting of the second plurality of particles and the first intermediate material comprises mixing the first plurality of particles, the second plurality7of particles, and the third plurality7of particles with a rotary7mixer at about 5 rpm to about 50 rpm for about 30 seconds to about 5 minutes.

19. The method of claim 16, wherein the contacting of the matrix material and the second intermediate material comprises mixing the matrix material, the first plurality of particles, the second plurality of particles, and the third plurality of particles with a rotary mixer at about 5 rpm to about 60 rpm for about 10 minutes to about 30 minutes.

20. The method of claim 16, wherein, in the first intermediate material, one or more particles of the first plurality of particles is adhered to a particle of the third plurality of particles.

21. A method of improving heat transfer, the method comprising: providing the composite material of claim 1; arranging the composite material between and in contact with a surface of a first object and a surface of a second object; wherein the surface of the first object and the surface of the second object are at different temperatures prior to the arranging of the composite material.

22. The method of claim 21, wherein a temperature difference between the different temperatures of the surface of the first object and the surface of the second object is at least 20 °C.

23. The method of claim 21, wherein the first object is a pipe, a heat exchanger component, or a condenser.

24. The method of claim 21, wherein the second object is a tank.

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