Thermally conductive alignment material, its manufacturing method and its use

Abstract

The present disclosure generally relates to thermally conductive alignment materials for various purposes, including thermal interface materials for semiconductor devices or other applications. Some aspects relate to compositions that include discontinuous fibers that may be substantially aligned, for example, defining a substrate. The compositions may also include a polymer or phase change material in contact with at least a portion of the discontinuous fibers. The discontinuous fibers may optionally include carbon fibers. In some cases, the discontinuous fibers are aligned, for example, along the direction in which the fibers are aligned, to promote heat transfer. Other aspects generally relate to devices that use such compositions, methods of making such compositions, kits that include such compositions, and the like.

Description

[Technical field]

[0001] (Related Applications) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 314,808, filed Feb. 28, 2022, entitled "Thermal Conductive Alignment Material, Method for Manufacturing Same, and Method for Using Same," which is incorporated by reference in its entirety.

[0002] The present disclosure relates generally to thermally conductive alignment materials for a variety of purposes, including thermal interface materials for semiconductor devices or other applications. [Background technology]

[0003] A thermal interface material is a material with a relatively low thermal impedance that is used to conduct heat between a first location (e.g., a heat source) and a second location (e.g., a heat sink). As such, a thermal interface material can be used to aid in the transfer of heat between a first location and a second location.

[0004] Thermal interface materials are often used to dissipate heat in electronic devices. For example, semiconductor devices in computers often generate large amounts of heat, which can damage the chips and other components. Therefore, thermal interface materials are sometimes used to connect the semiconductor devices to a suitable heat sink, such as cooling fins.

[0005] However, many thermal interface materials are inefficient and do not have suitably high thermal conductivity, and therefore improvements are needed. Summary of the Invention

[0006] The present disclosure generally relates to thermally conductive alignment materials for a variety of purposes, including thermal interface materials for semiconductor devices or other applications. The subject matter of the present disclosure may in some cases include interrelated products, alternative solutions to a particular problem, and / or multiple different applications of one or more systems and / or articles.

[0007] In one aspect, the disclosure relates to a composition. In one set of embodiments, the composition includes a plurality of discontinuous fibers defining a substrate, and a phase change material in contact with at least a portion of the discontinuous fibers. In some cases, at least 30% by volume of the fibers in the substrate are substantially aligned. In some embodiments, the phase change material exhibits a phase change between 0°C and 80°C.

[0008] In another set of embodiments, the composition includes a plurality of discontinuous fibers defining a substrate and a polymer in contact with at least a portion of the discontinuous fibers. In some embodiments, at least 30% by volume of the fibers in the substrate are substantially aligned. In some embodiments, the polymer has a viscosity of less than 500 cP at a temperature of 60° C.

[0009] In yet another set of embodiments, the composition includes a substrate comprising 30 volume percent or less of a metal and a phase change material in contact with at least a portion of the discontinuous fibers, the substrate having a density of 2.7 g / cm 3 The phase change material has a density of less than 0.2 and a thermal conductivity of at least 5 W / m·K, and exhibits a phase change between 0°C and 300°C.

[0010] In yet another set of embodiments, the composition has a density of 2.7 g / cm 3 The substrate has a density of less than 100 nm and exhibits a through-thickness anisotropic thermal conductivity of at least 5 W / m·K.

[0011] In another aspect, the disclosure relates to a device. In one set of embodiments, the device includes a heat source, a cooling device, and a composition in physical contact with the heat source and the cooling device. In some embodiments, the composition comprises: (a) a plurality of discontinuous fibers defining a substrate; and (b) a phase change material in contact with at least a portion of the discontinuous fibers; At least 30% by volume of the fibers within the substrate are substantially aligned; The phase change material exhibits a phase change between 0°C and 80°C.

[0012] In another set of embodiments, the device includes a heat source, a cooling device, and a composition in physical contact with the heat source and the cooling device. In some embodiments, the composition includes: (a) a plurality of discontinuous fibers defining a substrate; and (b) a polymer in contact with at least a portion of the discontinuous fibers; At least 30% by volume of the fibers within the substrate are substantially aligned; The polymer has a viscosity of less than 500 cP at a temperature of 60°C.

[0013] In yet another set of embodiments, a device includes a heat source, a cooling apparatus, and a composition in physical contact with the heat source and the cooling apparatus. In some embodiments, the composition includes a plurality of discontinuous fibers defining a substrate, the composition having a through-thickness thermal conductivity of at least 30 W / m·K. In some cases, at least 30% by volume of the fibers within the substrate are substantially aligned.

[0014] In yet another series of embodiments, the device includes a heat source, a cooling device, and a composition in physical contact with the heat source and the cooling device. In some embodiments, the composition exhibits anisotropic thermal conductivity and has a through-thickness thermal conductivity of at least 30 W / m·K.

[0015] In another set of embodiments, the device comprises a heat source, a cooling device, and a composition in physical contact with the heat source and the cooling device. In some embodiments, the composition comprises: (a) a substrate comprising no more than 30% by volume of metal, the substrate having a mass of less than 2.7 g / cm 3 and a thermal conductivity of at least 5 W / m·K; and / or (b) a phase change material in contact with at least a portion of the discontinuous fibers, the phase change material exhibiting a phase change between 0°C and 300°C.

[0016] In yet another set of embodiments, the device comprises a heat source, a cooling device, and a composition in physical contact with the heat source and the cooling device. In some embodiments, the composition comprises: (a) a substrate comprising 30% or less by volume of particles, the substrate having a mass of 2.7 g / cm3 and (b) a substrate having a density of less than 100 nm and a thermal conductivity of at least 5 W / m·K; and / or (b) a phase change material in contact with at least a portion of the discontinuous fibers, the phase change material exhibiting a phase change between 0°C and 300°C.

[0017] Yet another aspect generally relates to a method. In one set of embodiments, the method includes providing a plurality of discontinuous fibers defining a substrate and exposing at least a portion of the discontinuous fibers to a phase change material. In some embodiments, at least 30% by volume of the fibers in the substrate are substantially aligned. In some embodiments, the phase change material exhibits a phase change between 0° C. and 80° C. and forms a discrete layer on at least one side of the substrate.

[0018] In another set of embodiments, the method includes providing a plurality of discontinuous fibers defining a substrate and exposing at least a portion of the discontinuous fibers to a polymer. In some embodiments, the polymer has a viscosity of less than 500 cP at a temperature of 60° C. In certain aspects, at least 30% by volume of the fibers within the substrate are substantially aligned.

[0019] In yet another set of embodiments, the composition includes a plurality of discontinuous fibers defining a substrate, and a matrix disposed in physical contact with a first side of the substrate but not in physical contact with a second side of the substrate. In some embodiments, at least 30% by volume of the fibers within the substrate are substantially aligned. In some aspects, the matrix secures first ends of the discontinuous fibers but not second ends.

[0020] In another aspect, the present disclosure includes a method of making one or more of the embodiments described herein, such as a thermally conductive alignment material. In yet another aspect, the present disclosure includes a method of using one or more of the embodiments described herein, such as a thermally conductive alignment material.

[0021] Other advantages and novel features of the present disclosure will become apparent from the following detailed description of various non-limiting embodiments of the present disclosure when considered in conjunction with the accompanying drawings. [Brief description of the drawings]

[0022] Non-limiting embodiments of the present disclosure are illustratively described with reference to the accompanying figures, which are schematic and are not intended to be drawn to scale. In the figures, each identical or nearly identical component shown is typically represented by a single numeral. For clarity, not every component is shown in every figure, nor are every component of each embodiment of the present disclosure shown if the illustration is not necessary for a person skilled in the art to understand the disclosure. [Figure 1] 1 is an SEM image of a composition according to an embodiment showing substantially aligned discontinuous fibers. [Diagram 2] 1 is an SEM image of a composition according to another embodiment showing embedded carbon fibers. [Diagram 3] 1 is an SEM image of a composition according to yet another embodiment showing carbon fibers embedded in paraffin wax. [Figure 4] FIG. 13 illustrates the thermal impedance of a composition in yet another embodiment. [Figure 5A] 1A-1C illustrate non-limiting examples of some devices according to various embodiments. [Figure 5B] 1A-1C illustrate non-limiting examples of some devices according to various embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The present disclosure generally relates to thermally conductive aligned materials for various purposes, such as as thermal interface materials for semiconductor devices or other applications. Some aspects relate to compositions that include discontinuous fibers that may be substantially aligned, for example, defining a substrate. The compositions may also include a polymer or phase change material in contact with at least a portion of the discontinuous fibers. The discontinuous fibers may optionally include carbon fibers. In some cases, the discontinuous fibers are aligned, for example, along the direction in which the fibers are aligned, to promote heat transfer. Other aspects generally relate to devices that use such compositions, methods of making such compositions, kits that include such compositions, and the like.

[0024] One aspect of the present disclosure generally relates to thermal interface materials (or TIMs) and compositions. These may be used, for example, to conduct heat between a first location (e.g., a heat source) and a second location (e.g., a heat sink). Such compositions may be disposed between a semiconductor device (e.g., a heat source or heating element) and a heat sink or cooling device (e.g., a thermal emitter). In some embodiments, thermally conductive carbon fibers can be used to rapidly and efficiently transport heat through the material. Additionally, in some embodiments, such compositions may be used, for example, to provide electromagnetic interference (EMI) shielding instead of or in addition to heat transport.

[0025] In one set of embodiments, materials such as polymers or phase change materials may be used in the composition. Non-limiting examples include silicones, acrylics, waxes, and other materials, including those discussed in more detail herein. In one set of embodiments, such compositions may be used to ensure good thermal contact between a first location and a second location, for example, between a heat source and a heat sink or cooling device. Additionally, in some embodiments, the composition may include a filler, such as a ceramic or metal filler, in addition to or instead of the polymer or phase change material.

[0026] In one set of embodiments, compositions such as those described herein may include a plurality of discontinuous fibers, which may in some cases be substantially aligned. It should be noted that such alignment need not be perfect, but at least a portion of the fibers in the composition may generally exhibit an alignment that is within 20° of the average alignment of the plurality of fibers, e.g., as discussed herein. In addition, in some embodiments, such fibers may be aligned at a relatively high volume fraction or packing fraction. For example, the fibers may be present in the composition such that at least 30% by volume of the composition comprises such fibers. Higher volume percentages are also possible in other embodiments, e.g., as discussed herein. Such fibers, e.g., when substantially aligned, may be particularly effective in transporting heat from a first location and a second location, e.g., due to the alignment and directionality of the fibers. In contrast, many other compositions used in thermal interface materials have much lower fiber concentrations or densities, and typically, the fibers that may be present are not able to transport significant amounts of heat, e.g., due to their low concentration.

[0027] Thus, some embodiments such as those discussed herein may relate to a substrate that includes or is defined by such discontinuous fibers, which may in some cases be substantially aligned. In some cases, a polymer or phase change material may be added. For example, such materials may be infused into the substrate using techniques such as applied pressure, gravity, capillary action, etc., as discussed in more detail herein. In some cases, additional materials may be coated onto the substrate.

[0028] A specific, non-limiting example of such a system will now be described with respect to Figure 5. In Figure 5A, an exemplary device 50 includes a heat source 20 (e.g., at a first location), a cooling device 10 (e.g., at a second location), and a composition 30 in physical contact with the heat source and the cooling device. For example, the heat source 20 may be a semiconductor microchip or other heat source as described herein. Similarly, the cooling device 10 may be a heat sink, a metal with a relatively high thermal conductivity, or other cooling device such as those described herein.

[0029] Between the heat source 20 and the cooling device 10 is a composition 30. The composition 30 includes, in this non-limiting example, a substrate 31, and a phase change material 32. In some cases, for example, as described herein, the substrate 31 may include a plurality of discontinuous fibers, which may in some cases be substantially aligned. The phase change material 32 may include a material that begins to soften (e.g., become gummy or runny, etc.) or liquefy upon exposure to heat from the device 50 (e.g., from the heating source 20). For example, the phase change material 32 may include a wax, or other material, including those described herein. Although there are two phase change materials in this figure, this is merely illustrative and in other cases there may be fewer or more phase change materials in the composition.

[0030] Another non-limiting example is shown in Figure 5B. In this figure, cooling device 10 may take the form of one or more cooling fins. Composition 30 is disposed between the cooling fins and heat source 20 such that phase change material 32 is in direct physical contact with heat source 20 but not with substrate 31. Substrate 31 may include a plurality of discontinuous fibers that are aligned in any suitable direction, such as parallel or perpendicular to the substrate itself, parallel or perpendicular to heat source 20, etc.

[0031] The foregoing discussion is a non-limiting example of some embodiments of the present invention that can be used to manufacture some thermally conductive alignment materials. However, other embodiments are possible. Thus, more generally, various aspects of the present invention relate to various systems and methods for thermally conductive alignment materials.

[0032] For example, various aspects generally relate to compositions that can conduct heat between a first location (e.g., a heat source) and a second location (e.g., a heat sink). In some embodiments, the compositions may be used as thermal interface materials that can be used to aid in the transfer of heat from a first location to a second location. In one set of embodiments, the compositions as discussed herein may have a relatively high thermal conductivity. For example, the composition may have an overall thermal conductivity of at least 3 W / m·K, at least 5 W / m·K, at least 10 W / m·K, at least 20 W / m·K, at least 25 W / m·K, at least 30 W / m·K, at least 35 W / m·K, at least 40 W / m·K, at least 45 W / m·K, at least 50 W / m·K, at least 60 W / m·K, at least 75 W / m·K, at least 100 W / m·K, at least 200 W / m·K, at least 250 W / m·K, at least 300 W / m·K, at least 350 W / m·K, at least 400 W / m·K, at least 450 W / m·K, at least 500 W / m·K, at least 600 W / m·K, at least 750 W / m·K, etc.

[0033] In one set of embodiments, the composition may have a density of less than 5 g / mL, less than 4.5 g / mL, less than 4 g / mL, less than 3.5 g / mL, less than 3 g / mL, less than 2.9 g / mL, less than 2.8 g / mL, less than 2.7 g / mL, less than 2.6 g / mL, less than 2.5 g / mL, less than 2.4 g / mL, less than 2.2 g / mL, less than 2 g / mL, less than 1.5 g / mL, etc. Without wishing to be bound by any theory, it is believed that relatively low densities for use in heat sinks and some other applications, such as those discussed herein, have not previously been achievable because such materials often rely on metals, which have relatively high densities. Surprisingly, as discussed herein, relatively high overall thermal conductivity may be achieved according to some embodiments without relying on metals or other high density materials.

[0034] Thus, for example, in some embodiments, the composition may include a plurality of discontinuous fibers and a polymer or phase change material in contact with at least some of the discontinuous fibers. The discontinuous fibers may include carbon fibers and / or other fibers formed with materials such as those described herein. In some cases, the plurality of discontinuous fibers may be substantially aligned, which may surprisingly allow for significantly improved heat transport, for example, along the alignment or thickness direction. In some cases, the thickness direction may be substantially perpendicular to the plane of the substrate. Such compositions may, in some embodiments, provide improved heat transport due to the close packing of the discontinuous fibers. For example, at least 30% by volume (or other percentages such as those described herein) of the fibers may be substantially aligned, which may result in improved heat transport within the composition.

[0035] In addition, in some embodiments, the composition may be useful as a shield against electromagnetic interference instead of or in addition to heat transport. In some cases, by increasing the bulk electrical conductivity of the material, the material can absorb electromagnetic waves, thereby shielding against electromagnetic interference. Electromagnetic shielding may be partial or total, depending on the application. In some cases, shielding may reduce the coupling of waves, electromagnetic fields, electrostatic fields, etc., due to, for example, conductive elements in the composition, such as carbon fibers or other fibers as described herein. In addition, in some embodiments, an increase in the thermal conductivity of the composition may also correspond to an increase in electrical conductivity and / or an increase in the shielding rate against electromagnetic interference.

[0036] Thus, one aspect generally relates to a plurality of discontinuous fibers. In some embodiments, there may be a relatively large number of discontinuous fibers, for example, such that they can define a substrate. A non-limiting example is shown in FIG. The discontinuous fibers may form a relatively large proportion of the substrate. For example, at least 20% by volume, at least 30% by volume, at least 40% by volume, at least 50% by volume, at least 60% by volume, at least 70% by volume, at least 80% by volume, at least 90% by volume, at least 95% by volume, at least 97% by volume, or at least 99% by volume of the substrate may be formed from discontinuous fibers.

[0037] Further, in some embodiments, some or all of the discontinuous fibers may be substantially aligned. Methods for aligning discontinuous fibers are described in more detail below. However, it should be understood that the alignment need not be perfect. For example, in some embodiments as described herein, at least 5% or more of the fibers in a substrate or composite may exhibit an alignment within 20° of the average alignment of a plurality of fibers.

[0038] In addition to the discontinuous fibers, there may also be materials such as polymers or phase change materials present in the composition according to some embodiments. Without wishing to be bound by any theory, it is believed that such materials may be particularly useful because they can form good thermal contact between the material and other components of the device, such as heat sources, heat sinks, cooling devices, etc. In some cases, such materials may partially or completely soften or liquefy when exposed to relatively warm temperatures, e.g., to improve thermal contact with such components. For example, in one set of embodiments, the composition may include a phase change material that begins to soften (e.g., become rubbery or liquid, etc.) or liquefy when the device in which it is contained is used (e.g., produces heat). As a non-limiting example, the device may include a semiconductor microchip, e.g., in a computer, and the microchip may be heated to a temperature of 40°C to 80°C, 50°C to 70°C, etc., during use. In some embodiments, even higher temperatures may be possible. In such cases, the phase change material may soften or liquefy at such higher temperatures, which may improve thermal contact with the semiconductor microchip, e.g., facilitating the transport of heat therefrom.

[0039] Any of a wide variety of phase change materials may be used. Generally, phase change materials may undergo a phase change due to heat, for example, from a heat source. For example, the material may undergo a phase change from a solid to a liquid (e.g., by heating through a Tm), from a crystalline state to an amorphous or rubbery state (e.g., by heating through a Tg), etc. Without wishing to be bound by any theory, it is believed that phase change materials are useful in some cases because they may be able to flow when heated, for example, to seal cracks, loose connections, etc., and / or because they absorb thermal energy (e.g., to effect a phase change) rather than increasing in temperature, at least until the phase change is complete. In some embodiments, one or more phase change materials may be present.

[0040] In some cases, the phase change material is one that exhibits a phase change at the operating temperature of the device. For example, the phase change material may exhibit a phase change at a temperature of at least 0° C., at least 10° C., at least 20° C., at least 30° C., at least 40° C., at least 50° C., at least 60° C., at least 70° C., at least 80° C., at least 90° C., at least 100° C., at least 125° C., at least 150° C., at least 175° C., at least 200° C., at least 250° C., at least 275° C., at least 300° C., etc. In some cases, the phase change material may exhibit a phase change at temperatures of 300° C. or less, 275° C. or less, 250° C. or less, 225° C. or less, 200° C. or less, 175° C. or less, 150° C. or less, 125° C. or less, 150° C. or less, 125° C. or less, 100° C. or less, 90° C. or less, 80° C. or less, 70° C. or less, 60° C. or less, 50° C. or less, 40° C. or less, 30° C. or less, 20° C. or less, 10° C. or less, etc. Combinations of these are also possible. For example, the phase change material may exhibit a phase change between 0° C. and 80° C., between 40° C. and 80° C., between 50° C. and 70° C., between 30° C. and 50° C., between 40° C. and 60° C., between 0° C. and 300° C., etc.

[0041] Further, in some embodiments, the phase change material may flow relatively easily, for example at temperatures equal to or greater than the phase change temperature. For example, the phase change material may have a viscosity of less than 1000 cP, less than 500 cP, less than 100 cP, less than 50 cP, or less than 10 cP at temperatures of 40° C., 50° C., or 60° C.

[0042] The discontinuous fibers may be in partial or complete contact with the phase change material. For example, in one embodiment, the discontinuous fibers may be completely embedded within the phase change material. In another embodiment, the discontinuous fibers may be in contact with the phase change material at a first end but not at a second end. For example, the second end may be in contact with a different material or may be free in some embodiments.

[0043] A variety of materials may be used as the phase change material. Non-limiting examples of phase change materials include silicone, acrylic, thermoplastics, etc. Other examples include trimethylolethane, lithium nitrate, manganese nitrate, manganese chloride, etc.

[0044] As another example, in one set of embodiments, the phase change material may include a wax. The wax may include alkanes and / or lipids and may be naturally occurring or artificially produced. In some cases, the wax is substantially water insoluble. In some cases, the wax may have a melting point (or melting temperature) of at least 40° C., or other phase change temperature, such as any described herein. Non-limiting examples of waxes include paraffin wax, polyethylene wax, hydrocarbon wax, beeswax, cetyl palmitate, vegetable wax, montan wax, lauric acid, and the like.

[0045] As yet another example, the phase change material may include a salt hydrate. Non-limiting examples of salt hydrates include potassium fluoride tetrahydrate, manganese nitrate hexahydrate, calcium chloride hexahydrate, calcium bromide hexahydrate, lithium nitrate hexahydrate, sodium sulfate decahydrate, sodium carbonate decahydrate, sodium orthophosphate dodecahydrate, zinc nitrate hexahydrate, sodium sulfate decahydrate, etc. For example, in one embodiment, the salt hydrate may have the formula NaCl·Na2SO4·10H2O.

[0046] As yet another example, the phase change material may include a eutectic. Typically, a eutectic is a mixture of two or more substances that has a lower melting point than any of the substances that form the eutectic. For example, the eutectic may have a melting point between 0°C and 80°C, or other phase change temperatures such as any described herein. As a non-limiting example, the eutectic may be an organic-organic eutectic or an organic-inorganic eutectic. Specific non-limiting examples include myristic acid and stearic acid, Mg(NO3)2·6H2O and glutaric acid, ethylene glycol distearate, etc.

[0047] Further examples of co-crystals include, but are not limited to, tetradecane and hexadecane, tetradecane and docosane, tetradecane and genicosane, caprylic acid and lauric acid, pentadecane and heneicosane, caprylic acid and palmitic acid, dodecanol and caprylic acid, pentadecane and docosane, pentadecane and octadecane, hexadecane and tetradecane, capric acid and lauric acid and cineole, capric acid and lauric acid and methyl salicylate, capric acid and lauric acid and pentadecane, capric acid and lauric acid, triethylolethane and water and urea, capric acid and lauric acid and eugenol, capric acid and lauric acid, butyl palmitate and butyl stearate, methyl palmitate and methyl stearate, capric acid and palmitic acid, octadecane and docosane, octadecane and heneicosane, capric acid and steric acid, and the like.

[0048] Further, it should be understood that a phase change material is not required. In another set of embodiments, the composition may include, for example, a polymer, which may in some cases be a relatively soft polymer, in addition to or instead of the phase change material. For example, in one set of embodiments, the polymer may be one that can readily flow at the operating temperatures of the device. For example, the polymer may exhibit flow properties at temperatures of at least 0° C., at least 10° C., at least 20° C., at least 30° C., at least 40° C., at least 50° C., at least 60° C., at least 70° C., etc., and / or at temperatures of 80° C. or less, 70° C. or less, 60° C. or less, 50° C. or less, 40° C. or less, 30° C. or less, 20° C. or less, 10° C. or less, etc. Combinations of these are also possible. For example, the polymer may be one that can readily flow at temperatures of 0° C. to 80° C., 40° C. to 80° C., 50° C. to 70° C., 30° C. to 50° C., 40° C. to 60° C., etc. For example, the polymers may have a viscosity at these temperatures of less than 1000 cP, less than 500 cP, less than 100 cP, less than 50 cP, less than 10 cP, or less than 5 cP. As previously mentioned, in some cases, such polymers have the ability to flow when heated, making them useful, for example, for sealing cracks, loose connections, and the like.

[0049] Examples of such polymers include, but are not limited to, silicones, acrylics, phase change materials, thermosets, and / or thermoplastics. Specific non-limiting examples include epoxy, polyaryletherketone (PAEK), polyimide (PI), polyamide-imide (PAI), polyetheretherketone (PEEK), polyetherketone (PEK), polyphenylsulfone (PPSU), polyethersulfone (PES), polyetherimide (PEI), polysulfone (PSU), polyphenylene sulfide (PPS), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), polyamide 46 (PA46), polyamide 66 (PA66), polyamide 12 (PA12), polyamide 11 (PA11), polyamide 6 (PA6), polyamide 6.6 (PA6.6), polyamide 6.6 / 6 (PA6.6 / 6), amorphous polyamide (PA6-3-T), polyethylene terephthalate (PET), polyf Poly(vinyl chloride) (PVC), polyparaphenylene copolymer (PPP), polyacrylonitrile, polyethylenimine, polyether ketone ether ketone ketone (PEKEKK), ethylene tetrafluoroethylene (ETFE), polychlorotrifluoroethylene (PCTFE), polymethylpentene (PMP), and others.

[0050] As mentioned above, the composition may include a plurality of discontinuous fibers in various aspects. In some cases, the discontinuous fibers may be substantially aligned, for example, defining a substrate. In some embodiments, at least 20% by volume, at least 30% by volume, at least 40% by volume, at least 50% by volume, at least 60% by volume, at least 70% by volume, at least 80% by volume, at least 90% by volume, at least 95% by volume, at least 97% by volume, at least 99% by volume, etc. of the substrate may include discontinuous fibers. Furthermore, at least 20% by volume, at least 30% by volume, at least 40% by volume, at least 50% by volume, at least 60% by volume, at least 70% by volume, at least 80% by volume, at least 90% by volume, at least 95% by volume, at least 97% by volume, or at least 99% by volume of the substrate may be formed from discontinuous fibers.

[0051] The discontinuous fibers may be formed from or comprise any of a wide variety of materials, and one or more materials may be present. For example, the discontinuous fibers may comprise materials such as carbon (e.g., carbon fiber), basalt, silicon carbide, silicon nitride, aramid, zirconia, nylon, boron, alumina, silica, borosilicate, mullite, nitride, boron nitride, graphite, glass, polymers (including any of those described herein). The discontinuous fibers may comprise any natural material and / or any synthetic material, and may be magnetic and / or non-magnetic.

[0052] Additionally, in some cases, the discontinuous fibers may be formed from a material having a relatively high thermal conductivity. For example, in various embodiments, the discontinuous fibers may have a thermal conductivity of at least 5 W / m·K, at least 10 W / m·K, at least 100 W / m·K, at least 200 W / m·K, at least 250 W / m·K, at least 300 W / m·K, at least 350 W / m·K, at least 400 W / m·K, at least 450 W / m·K, at least 500 W / m·K, at least 600 W / m·K, at least 750 W / m·K, at least 900 W / m·K, at least 1000 W / m·K, etc.

[0053] In some embodiments, the discontinuous fibers may be at least substantially aligned. Methods for aligning discontinuous fibers are discussed in more detail herein. Various alignments are possible and in some cases can be determined, for example, optically or microscopically. Thus, in some cases, the alignment may be determined qualitatively. However, it should be understood that the alignment need not be perfect. In some cases, at least 5%, at least 10%, at least 25%, at least 50%, at least 75%, at least 85%, at least 90%, or at least 95% of the fibers may be substantially aligned, or may exhibit an alignment within 20°, within 15°, within 10°, or within 5° of the average alignment of a plurality of fibers within a sample of the substrate, for example.

[0054] Further, in some cases, the average alignment of the fibers may be oriented at at least 45°, at least 60°, at least 65°, at least 70°, at least 75°, at least 85°, or at least 87° relative to the plane of the substrate at that location. Without wishing to be bound by any theory, it is believed that the alignment of discontinuous fibers substantially perpendicular to the substrate within the composition may help provide structural reinforcement for the substrate and / or the ability to transfer heat preferentially in a direction along the direction of the discontinuous fibers, such that, for example, the composition may exhibit anisotropic thermal conductivity. For example, the composition may exhibit a unidirectional thermal conductivity of at least 3 W / m·K, at least 5 W / m·K, at least 10 W / m·K, at least 30 W / m·K, at least 50 W / m·K, at least 100 W / m·K, 250 W / m·K, at least 500 W / m·K, at least 750 W / m·K, etc. For example, this may be a direction defined by the average alignment of the discontinuous fibers, or through the thickness of the substrate, e.g., substantially perpendicular to the plane of the substrate, in some embodiments, this can improve heat transfer, e.g., away from the heat source.

[0055] Although it has sometimes been proposed to fill the substrate with fibers, it is believed that higher fiber volume fractions have not been previously achievable, for example, in thermal interface materials. Without wishing to be bound by any theory, it is believed that this may be due to higher electrostatic interactions that cause fiber clumping and / or higher viscosity of the polymer resin that prevents consistent dispersion. Thus, some embodiments as discussed herein generally relate to fiber volume fractions (e.g., of substantially aligned fibers as previously described herein) of at least 40% fiber volume, at least 45% fiber volume, at least 50% fiber volume, at least 55% fiber volume, at least 60% fiber volume, at least 65% fiber volume, at least 70% fiber volume, etc.

[0056] As described in more detail below, various techniques may be used to align the discontinuous fibers in various embodiments, including magnetic fields, shear flow, etc. As a non-limiting example, magnetic particles, including those discussed herein, may be attached to the fibers, and then a magnetic field may be used to manipulate the magnetic particles. For example, a magnetic field may be used to move the magnetic particles into the substrate and / or align the discontinuous fibers. The magnetic field may be constant or time-varying (e.g., oscillating), for example, as discussed herein. For example, the applied magnetic field may have a frequency of 1 Hz to 500 Hz and an amplitude of 0.01 T to 10 T.

[0057] In some cases, the discontinuous fibers may have an average length or a characteristic dimension of at least 1 nm, at least 3 nm, at least 5 nm, at least 10 nm, at least 30 nm, at least 50 nm, at least 100 nm, at least 300 nm, at least 500 nm, at least 1 μm, at least 3 μm, at least 5 μm, at least 10 μm, at least 20 μm, at least 30 μm, at least 50 μm, at least 100 μm, at least 200 μm, at least 300 μm, at least 500 μm, at least 1 mm, at least 2 mm, at least 3 mm, at least 5 mm, at least 10 mm, at least 15 mm, etc. In some embodiments, the discontinuous fibers may have an average length or characteristic dimension of 5 cm or less, 3 cm or less, 2 cm or less, 1.5 cm or less, 1 cm or less, 5 mm or less, 3 mm or less, 2 mm or less, 1 mm or less, 500 μm or less, 300 μm or less, 200 μm or less, 100 μm or less, 50 μm or less, 30 μm or less, 20 μm or less, 10 μm or less, 5 μm or less, 3 μm or less, 1 μm or less, 500 nm or less, 300 nm or less, 100 nm or less, 50 nm or less, 30 nm or less, 10 nm or less, 5 nm or less, etc. Combinations of these are also possible. For example, the discontinuous fibers may have an average length of 1 mm to 5 mm.

[0058] Further, the discontinuous fibers may have any suitable average diameter. For example, the discontinuous fibers may have an average diameter of at least 5 μm, at least 10 μm, at least 20 μm, at least 30 μm, at least 50 μm, at least 100 μm, at least 200 μm, at least 300 μm, at least 500 μm, at least 1 mm, at least 2 mm, at least 3 mm, at least 5 mm, at least 1 cm, at least 2 cm, at least 3 cm, at least 5 cm, at least 10 cm, etc. In some embodiments, the discontinuous fibers may have an average diameter of 10 cm or less, 5 cm or less, 3 cm or less, 2 cm or less, 1 cm or less, 5 mm or less, 3 mm or less, 2 mm or less, 1 mm or less, 500 μm or less, 300 μm or less, 200 μm or less, 100 μm or less, 50 μm or less, 30 μm or less, 20 μm or less, 10 μm or less, 5 μm or less, etc. Combinations of these are also possible. For example, the discontinuous fibers may have an average diameter of 5 μm to 50 μm, 10 μm to 100 μm, 50 μm to 500 μm, 100 μm to 5 mm, etc.

[0059] In some embodiments, the discontinuous fibers may have, on average, a length at least 10 times or at least 50 times its thickness or diameter. In some cases, the fibers may have an average aspect ratio (ratio of fiber length to diameter or thickness) of at least 3, at least 5, at least 10, at least 30, at least 50, at least 100, at least 300, at least 500, at least 1,000, at least 3,000, at least 5,000, at least 10,000, at least 30,000, at least 50,000, or at least 100,000. In some cases, the average aspect ratio may be less than 100,000, less than 50,000, less than 30,000, less than 10,000, less than 5,000, less than 3,000, less than 1,000, less than 500, less than 300, less than 100, less than 50, less than 30, less than 10, less than 5, etc. Any combination of these is possible in some cases; for example, the aspect ratio may be from 5 to 100,000.

[0060] At least some of the discontinuous fibers may be uncoated. However, in some cases, some or all of the discontinuous fibers may be coated. Coatings may be used, for example, to facilitate the adsorption or binding of particles, such as magnetic particles, onto the fibers, or for other reasons. As a non-limiting example, at least some of the discontinuous fibers are coated with a sizing agent. Some examples of coatings or sizing agents include, but are not limited to, polypropylene, polyurethane, polyamide, phenoxy, polyimide, epoxy, and the like. These may be introduced, for example, as a solution, dispersion, emulsion, and the like. As other examples, the fibers may be coated with surfactants, silane coupling agents, epoxies, glycerin, polyurethanes, organometallic coupling agents, and the like. Non-limiting examples of surfactants include oleic acid, sodium dodecyl sulfate, sodium lauryl sulfate, and the like. Non-limiting examples of silane coupling agents include amino, benzylamino, chloropropyl, disulfide, epoxy, epoxy / melamine, mercapto, methacrylate, tetrasulfide, ureido, vinyl, isocyanate, and vinyl-benzylamino silane coupling agents. Non-limiting examples of organometallic coupling agents include aryl- and vinyl-based organometallic coupling agents.

[0061] As mentioned above, in one set of embodiments, at least some of the discontinuous fibers may be carbon fibers. The carbon fibers may be aligned in a magnetic field, either directly or indirectly, using, for example, magnetic particles or other techniques as discussed herein. For example, some types of carbon fibers are diamagnetic and can be moved directly using an applied magnetic field. Thus, some embodiments relate to fibers that are substantially free of paramagnetic or ferromagnetic materials and can be aligned using an external magnetic field. For example, if paramagnetic or ferromagnetic materials are present, they may form less than 5%, less than 1%, less than 0.5%, less than 0.3%, less than 0.1%, less than 0.05%, less than 0.03%, less than 0.01%, less than 0.005%, less than 0.003%, or less than 0.001% (by mass) of the material.

[0062] A variety of carbon fibers are commercially available, including diamagnetic carbon fibers. In some cases, carbon fibers can be produced from polymer precursors such as polyacrylonitrile (PAN), rayon, pitch, etc. In some cases, carbon fibers can be spun into filament yarns, for example using chemical or mechanical methods to initially align the polymer atoms in a manner that enhances the final physical properties of the finished carbon fiber. The precursor compositions and mechanical methods used in spinning the filament yarns vary. After drawing or spinning, the polymer filament yarns can be heated to drive off non-carbon atoms (carbonization or pyrolysis) to produce the final carbon fibers. In some embodiments, such techniques may be used to produce carbon fibers with a relatively high carbon content, for example at least 90%, or other content as described herein.

[0063] Non-limiting examples of carbon fibers include pitch-based and / or polymer-based (e.g., ex-PAN or ex-Rayon) varieties, including, for example, commercially available products. In some cases, these may include medium / standard modulus (greater than 200 GPa), high modulus (greater than 300 GPa), or ultra-high modulus (greater than 500 GPa) carbon fibers.

[0064] In one set of embodiments, the carbon fibers have a relatively high carbon content. Without wishing to be bound by any theory, it is believed that such fibers may exhibit diamagnetic properties that can be oriented with a low energy magnetic field. In general, diamagnetism is the repulsion of a material to an applied magnetic field by generating an induced magnetic field that opposes the applied magnetic field. A material is generally classified as diamagnetic if the contribution of paramagnetic or ferromagnetic materials is not significant in the overall magnetic response. In many cases, the magnetic response of diamagnetic materials is very weak and can be ignored. However, relatively high magnetic fields can induce a significant physical response in such diamagnetic materials.

[0065] Thus, in some cases, carbon fibers exhibiting a relatively highly-oriented molecular structure may exhibit anisotropic, highly magnetic, diamagnetic properties. Such diamagnetic properties may allow for orientation with relatively weak magnetic fields, such as those described herein. For example, in one set of embodiments, an applied magnetic field may cause the C-C bonds of the carbon fibers to generate a strong induced magnetic field in the opposite direction of the applied magnetic field. Some types of carbon fibers may have a high degree of C-C bonds parallel to the in-fiber direction, which may produce an anisotropic diamagnetic response. Such carbon fibers may therefore be subject to a magnetic torque that would be neutralized if the carbon fibers were perfectly aligned parallel to the applied magnetic field. Thus, by applying a suitable magnetic field, the carbon fibers may be aligned due to such diamagnetic properties. This response may be sufficient to overcome gravitational, viscous, and / or inter-particle steric effects.

[0066] For example, in some embodiments, the carbon fibers may have a carbon content of greater than 80%, greater than 90%, greater than 92%, greater than 94%, greater than 95%, greater than 96%, greater than 97%, greater than 98%, greater than 99%, or greater than 99.5% by weight. Such carbon fibers are sometimes commercially available. For example, carbon fibers can be produced, for example, pyrolytically, by "burning" or oxidizing (e.g., by gasifying) other components that can be removed, leaving carbon fibers with a relatively high carbon content. Other methods of producing carbon fibers are also possible, for example, as described in detail herein.

[0067] Carbon fibers may, in some cases, exhibit substantial alignment of C-C bonds within the carbon fibers. For example, at least 50%, at least 60%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, or at least 95% of the carbon fibers may exhibit substantial alignment of C-C bonds. Such alignment may be determined, for example, using wide angle x-ray diffraction (WAXD) or other techniques known to those skilled in the art.

[0068] In one set of embodiments, the carbon fibers (or other discontinuous fibers) may have a relatively high modulus of elasticity (tensile modulus, which is a measure of stiffness). Generally, high modulus fibers are stiffer and lighter than low modulus fibers. Carbon fibers generally have a higher modulus of elasticity when force is applied parallel to the fiber, i.e., the carbon fibers are anisotropic. In some embodiments, the carbon fibers (or other discontinuous fibers) may have a modulus of elasticity (e.g., when force is applied parallel to the fiber) of at least 100 GPa, at least 200 GPa, at least 300 GPa, at least 400 GPa, at least 500 GPa, at least 600 GPa, at least 700 GPa, etc. It is believed that softer carbon fibers may exhibit less alignment, i.e., carbon fibers with a low modulus of elasticity may have little or no physical response to a magnetic field, rather than aligning in the applied magnetic field.

[0069] In one set of embodiments, carbon fibers (or other discontinuous fibers) may be free-floating in a liquid (e.g., water, oil, polymer resin, polymer melt, metal melt, alcohol such as ethanol, or other volatile organic compounds) and may exhibit an anisotropic diamagnetic response when a magnetic field is applied. For example, in some cases, the carbon fibers may align, i.e., exhibit a diamagnetic response, when a suitable magnetic field is applied. In some cases, the magnetic field may be at least 100 mT, at least 200 mT, at least 300 mT, at least 500 mT, at least 750 mT, at least 1 T, at least 1.5 T, at least 2 T, at least 3 T, at least 4 T, at least 5 T, at least 10 T, etc. In some cases, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90% of the free-floating carbon fibers in the liquid may exhibit alignment when a suitable magnetic field is applied.

[0070] Typically, a fiber has a shape such that one orthogonal dimension (e.g., its length) is substantially greater than the other two orthogonal dimensions (e.g., its width or thickness). The fiber may be substantially cylindrical in some cases. As previously mentioned, the carbon fiber may be relatively rigid in some cases, but the carbon fiber need not be perfectly straight (e.g., its length may be determined along the fiber itself even if it is curved).

[0071] As mentioned above, in one set of embodiments, particles such as magnetic particles may be added, for example, to align the discontinuous fibers or for other applications. The particles may be adsorbed or otherwise bound to at least some of the discontinuous fibers. In some cases, the particles may coat some or all of the discontinuous and / or continuous fibers. A coating is not necessary to facilitate particle adsorption, but this may be facilitated by a coating of a material as discussed herein.

[0072] If the particles are magnetic, they may comprise any of a wide variety of magnetically susceptible materials. For example, the magnetic material may comprise one or more ferromagnetic materials, including, for example, iron, nickel, cobalt, alnico; oxides of iron, nickel, cobalt, rare earth metals, or alloys comprising two or more of these and / or other suitable ferromagnetic materials. In some cases, the magnetic particles may have a relative permeability of at least 2, at least 5, at least 10, at least 20, at least 40, at least 100, at least 200, at least 500, at least 1,000, at least 2,000, at least 5,000, or at least 10,000.

[0073] However, it should be understood that not all particles are necessarily magnetic. In some cases, for example, non-magnetic particles may be used in addition to and / or instead of magnetic particles. Non-limiting examples of non-magnetic particles include glass, polymers, metals, etc. Furthermore, in some embodiments, no particles are present.

[0074] The particles (if present) may be spherical or non-spherical and may have any suitable shape or size. The particles may be relatively monodisperse or may vary in size. In some cases, the particles may have a characteristic dimension of at least 10 μm, at least 20 μm, at least 30 μm, at least 50 μm, at least 100 μm, at least 200 μm, at least 300 μm, at least 500 μm, at least 1 mm, at least 2 mm, at least 3 mm, at least 5 mm, at least 1 cm, at least 1.5 cm, at least 2 cm, at least 3 cm, at least 5 cm, at least 10 cm, etc. The particles may also have a characteristic average dimension of 10 cm or less, 5 cm or less, 3 cm or less, 2 cm or less, 1.5 cm or less, 1 cm or less, 5 mm or less, 3 mm or less, 2 mm or less, 1 mm or less, 500 μm or less, 300 μm or less, 200 μm or less, 100 μm or less, 50 μm or less, 30 μm or less, 20 μm or less, 10 μm or less, etc. Combinations of these are also possible. For example, the particles may exhibit a characteristic dimension between 100 μm and 1 mm, between 10 μm and 10 μm, etc. The characteristic dimension of a non-spherical particle may be the diameter of a perfect sphere having the same volume as the non-spherical particle.

[0075] In addition, in some embodiments, the substrate may further include, for example, fillers or additional materials in addition to the discontinuous fibers. For example, in one set of embodiments, the substrate includes a plurality of continuous fibers. The continuous fibers may have, on average, a length that is substantially longer than the cross-sectional dimension of the discontinuous fibers. For example, the continuous fibers may have an average length of at least about 0.5 cm, at least 1 cm, at least 2 cm, at least 3 cm, at least 5 cm, at least 10 cm, etc. In some embodiments, the continuous fibers may have an average diameter of 10 cm or less, 5 cm or less, 3 cm or less, 2 cm or less, 1 cm or less, 0.5 cm or less, etc. Any combination of these is also possible, for example, the continuous fibers may have an average length of 1 cm to 10 cm, 10 cm to 100 cm, etc. Longer average lengths are also possible in some cases.

[0076] The continuous fibers may be woven together (e.g., bidirectional, multidirectional, quasi-isotropic, etc.) and / or non-woven (e.g., unidirectional, veils, mats, etc.). In some embodiments, at least a portion of the continuous fibers are substantially parallel and / or oriented orthogonally relative to one another, although other configurations of continuous fibers are possible. In some embodiments, the continuous fibers may cooperate to define a fabric or other substrate, such as a fabric, a tow, a filament, a yarn, a strand, etc. In some cases, the substrate may have one orthogonal dimension that is substantially smaller than the other orthogonal dimension (i.e., the substrate may have a thickness). The continuous fibers may also comprise any of a wide variety of materials, and one or more types of fibers may be present within the substrate. Non-limiting examples include carbon, basalt, silicon carbide, aramid, zirconia, nylon, boron, alumina, silica, borosilicate, mullite, cotton, or other natural or synthetic fibers.

[0077] In some embodiments, the continuous fibers may constitute a relatively large portion of the composite. For example, in some embodiments, the continuous fibers may constitute at least 1%, at least 2%, at least 3%, at least 4%, at least 5%, at least 7%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or at least 97% of the mass or volume of the composite. In some cases, the continuous fibers constitute 97% or less, 95% or less, 90% or less, 85% or less, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, or 10% or less of the mass or volume of the composite. Any combination of these is also possible.

[0078] In some cases, one or more fillers may be present in the substrate. For example, in some embodiments, the substrate may further include one or more ceramics, such as boron nitride, alumina, titania, etc. Furthermore, in some embodiments, the substrate may further include one or more metals, such as aluminum, copper, silver, tin, gold, etc. Furthermore, in one embodiment, such materials present in the substrate may be formed, for example, by fusing particles during formation of the substrate. Other materials may also be present in the substrate in some cases.

[0079] As mentioned above, some embodiments generally relate to compositions that include, for example, a plurality of discontinuous fibers and a phase change material or other material such as those described herein. In some cases, the composition may be generally planar and / or include one (or more) substrates. However, it should be understood that the substrate or composition need not (although it can) be a mathematically perfect planar structure, e.g., the substrate or composition may also be deformable, curved, bent, folded, rolled, creased, etc. By way of example, the substrate may have an average thickness of at least about 0.1 μm, at least about 0.2 μm, at least about 0.3 μm, at least about 0.5 μm, at least about 1 μm, at least about 2 μm, at least about 3 μm, at least about 5 μm, at least about 10 μm, at least about 30 μm, at least about 50 μm, at least about 100 μm, at least about 300 μm, at least about 500 μm, at least about 1 mm, at least about 2 mm, at least about 3 mm, at least about 5 mm, at least about 1 cm, at least about 3 cm, at least about 5 cm, at least about 10 cm, at least about 30 cm, at least about 50 cm, at least about 100 cm, etc. In some examples, the average thickness may be less than 100 cm, less than 50 cm, less than 30 cm, less than 10 cm, less than 5 cm, less than 3 cm, less than 1 cm, less than 5 mm, less than 3 mm, less than 2 mm, less than 1 mm, less than 500 μm, less than 300 μm, less than 100 μm, less than 50 μm, less than 30 μm, less than 10 μm, less than 5 μm, less than 3 μm, less than 1 μm, less than 0.5 μm, less than 0.3 μm, or less than 0.1 μm. In some embodiments, any combination of these is also possible. For example, the average thickness may be 0.1 to 5,000 μm, 10 to 2,000 μm, 50 to 1,000 μm, etc. The thickness may be uniform or non-uniform across the substrate. The substrate may also be deformable in some cases.

[0080] In some embodiments, the composition comprises at least 50 g / m 2and in some embodiments, the composition may have a basis weight (or areal weight) of at least 100 g / m 2 , at least 150 g / m 2 , at least 200 g / m 2 , at least 250 g / m 2 , at least 300 g / m 2 , at least 400 g / m 2 , at least 500g / m 2 , at least 750 g / m 2 , at least 1000g / m 2 It will be understood by those skilled in the art that the area refers to the bulk or overall area of ​​the composition, and not the individual areas of any discontinuous fibers that may be present.

[0081] The composition may optionally include additional layers or materials, such as in addition to these. For example, the substrate may be one of multiple layers in the composition. Other layers in the composition may include polymers, composites, metals, ceramics, etc. For example, the composition may be consolidated with another layer to form a composite structure.

[0082] In some embodiments, compositions such as these may be used as a heat sink material and / or to conduct heat between a first location and a second location. A variety of compositions are possible, including, for example, discontinuous fibers such as those described herein, which may be aligned within the substrate, for example. However, it should be understood that in other embodiments, other compositions and methods may be used, for example, as a heat sink material and / or to conduct heat between a first location and a second location. In some cases, it may be possible to achieve a relatively high overall thermal conductivity according to some embodiments without resorting to metals or other high density materials. As a non-limiting example, in one embodiment, the material may have a density of less than 2.7 g / mL and / or a thermal conductivity of at least 20 W / m·K, for example, through the thickness.

[0083] In other examples, such as those discussed herein, the composition may have a thermal conductivity of at least 3 W / m·K, at least 5 W / m·K, at least 10 W / m·K, at least 20 W / m·K, at least 25 W / m·K, at least 30 W / m·K, at least 35 W / m·K, at least 40 W / m·K, at least 45 W / m·K, at least 50 W / m·K, at least 60 W / m·K, at least 75 W / m·K, at least 100 W / m·K, at least 200 W / m·K, at least 250 W / m·K, at least 300 W / m·K, at least 350 W / m·K, at least 400 W / m·K, at least 450 W / m·K, at least 500 W / m·K, at least 600 W / m·K, at least 750 W / m·K, etc. In some embodiments, the thermal conductivity may be through the thickness, e.g., substantially perpendicular to the plane of the substrate. Additionally, in some cases, the composition may have a density of less than 5 g / mL, less than 4.5 g / mL, less than 4 g / mL, less than 3.5 g / mL, less than 3 g / mL, less than 2.9 g / mL, less than 2.8 g / mL, less than 2.7 g / mL, less than 2.6 g / mL, less than 2.5 g / mL, less than 2.4 g / mL, less than 2.2 g / mL, less than 2 g / mL, less than 1.5 g / mL, etc.

[0084] In some embodiments, such materials may include a plurality of discontinuous fibers, for example, as discussed herein. The discontinuous fibers may include carbon fibers and / or other fibers formed using materials such as those described herein. However, in some embodiments, other materials are possible. For example, in one embodiment, the material may include a composite of particles (e.g., thermally conductive particles) and a polymer. In another embodiment, the material may include a ceramic, a metal, or the like.

[0085] In one set of embodiments, the material may include a metal. For example, the metal may be a pure metal or a metal alloy. Non-limiting examples of metals include aluminum, zinc, copper, magnesium, nickel, silver, gold, and the like. In some cases, alloys or combinations of these and / or other metals may be used. In addition, the metal may be solid or, in some embodiments, porous. Other examples of metals include any of those described herein.

[0086] In another set of embodiments, the material may include a ceramic. Non-limiting examples of ceramics include metal or non-metal oxides, metal or non-metal nitrides, metal or non-metal carbides, metal or non-metal borides, graphite, and the like. Specific non-limiting examples include boron nitride, titanium diboride, aluminum nitride, silicon nitride, silicon carbide, graphite, aluminum oxide, magnesium oxide, zinc oxide, beryllium oxide, antimony oxide, silicon oxide, and the like. In some cases, alloys or combinations of these and / or other ceramics may be used. Furthermore, the ceramic may be solid or, in some embodiments, porous. Other examples of ceramics include any of those described herein.

[0087] In another set of embodiments, the material may include particles. The particles may be thermally conductive in some embodiments. The particles may include metal particles (e.g., including metals such as those previously described), ceramic particles (e.g., including ceramics such as those previously described), and the like. Specific non-limiting examples of metals include aluminum, zinc, copper, magnesium, nickel, and the like. Examples of ceramics include, but are not limited to, oxides, nitrides, carbides, borides, graphite, and the like, including specific non-limiting examples of boron nitride, titanium diboride, aluminum nitride, silicon nitride, silicon carbide, graphite, aluminum oxide, magnesium oxide, zinc oxide, beryllium oxide, antimony oxide, silicon oxide, and the like.

[0088] The particles may be spherical or non-spherical and may have any suitable shape or size. For example, the particles may exist as spherical particles, platelets, fibers, etc. The particles may be relatively monodisperse or may be of various sizes. In some cases, the particles may have a characteristic dimension of at least 10 μm, at least 20 μm, at least 30 μm, at least 50 μm, at least 100 μm, at least 200 μm, at least 300 μm, at least 500 μm, at least 1 mm, at least 2 mm, at least 3 mm, at least 5 mm, at least 1 cm, at least 1.5 cm, at least 2 cm, at least 3 cm, at least 5 cm, at least 10 cm, etc. The particles in the composite may also have a characteristic average dimension of 10 cm or less, 5 cm or less, 3 cm or less, 2 cm or less, 1.5 cm or less, 1 cm or less, 5 mm or less, 3 mm or less, 2 mm or less, 1 mm or less, 500 μm or less, 300 μm or less, 200 μm or less, 100 μm or less, 50 μm or less, 30 μm or less, 20 μm or less, 10 μm or less, etc. Any combinations of these are also possible. For example, the particles may exhibit a characteristic dimension of 100 μm to 1 mm, 10 μm to 10 μm, etc. The characteristic dimension of a non-spherical particle may be the diameter of a perfect sphere having the same volume as the non-spherical particle.

[0089] In some embodiments, the particles may constitute a relatively large portion of the material. For example, in some embodiments, the particles may constitute at least 1%, at least 2%, at least 3%, at least 4%, at least 5%, at least 7%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or at least 97% of the volume of the composite. In some cases, the particles comprise 97% or less, 95% or less, 90% or less, 85% or less, 80% or less, 70% or less, 60% or less, 50% or less, 45% or less, 40% or less, 35% or less, 30% or less, 25% or less, 20% or less, 15% or less, 10% or less, 7% or less, 5% or less, 4% or less, 3% or less, 2% or less, or 1% or less by volume of the material, or any combination thereof.

[0090] In another set of embodiments, the material may include a polymer, such as a thermosetting polymer and / or a thermoplastic polymer. Non-limiting examples of thermosetting polymers include thermosetting alkyds, bismaleimide polymers, bismaleimide triazine polymers, cyanate ester polymers, vinyl ester polymers, benzocyclobutene polymers, diallyl phthalate polymers, epoxies, hydroxymethylfuran polymers, melamine-formaldehyde polymers, phenols, polyesters, benzoxazines, polydienes, polyisocyanates, polyureas, polyurethanes, silicones, liquid crystal elastomers, elastomers, polyimides, triallyl cyanurate polymers, or triallyl isocyanurate polymers, and the like, as well as blends, copolymers, and the like of these and / or other polymers.

[0091] Non-limiting examples of thermoplastic polymers include polyimide (PI), polyamide-imide (PAI), polyetheretherketone (PEEK), polyetherketone (PEK), polyphenylsulfone (PPSU), polyethersulfone (PES), polyetherimide (PEI), polysulfone (PSU), polyphenylene sulfide (PPS), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), polyamide 46 (PA46), polyamide 66 (PA66), polyamide 12 (PA12), polyamide 11 (PA11), polyamide 6 (PA6), polyamide 6.6 (PA6.6), polyamide 6.6 / 6 (PA6.6 / 6), amorphous polyamide (PA6-3-T), polyethylene terephthalate (PET), polyphthalamide (PPA), liquid crystal polymer (LCP), poly Included are polycarbonate (PC), polybutylene terephthalate (PBT), polyoxymethylene (POM), polyphenyl ether (PPE), polymethyl methacrylate (PMMA), polypropylene (PP), polyethylene (PE), high density polyethylene (HDPE), acrylonitrile-styrene-acrylate (ASA), styrene-acrylonitrile (SAN), acrylonitrile-butadiene-styrene (ABS), polybenzimidazole (PBI), polyvinyl chloride (PVC), poly-p-phenylene copolymer (PPP), polyacrylonitrile, polyethyleneimine, polyetherketoneetherketoneketone (PEKEKK), ethylenetetrafluoroethylene (ETFE), polychlorotrifluoroethylene (PCTFE), polymethylpentene, and the like, as well as blends, copolymers, and the like of these and / or other polymers. Other examples of thermoplastic and / or thermosetting polymers include any of those described herein.

[0092] Another aspect generally relates to systems and methods for producing compositions such as those described herein. In one set of embodiments, such compositions may be made from a liquid. The liquid may be, for example, a slurry, a solution, an emulsion, etc. The liquid may include discontinuous fibers such as those discussed herein. The fibers may then be aligned as discussed herein, and the liquid may then be removed, for example, to form a fiber-containing substrate. After alignment, the final composition may be formed, for example, by applying heat and / or pressure to remove the liquid.

[0093] In one set of embodiments, the liquid can neutralize electrostatic interactions between the discontinuous fibers, for example using an aqueous liquid. This can be useful, for example, to allow the discontinuous fibers to be dispersed in the liquid at a relatively high fiber volume without agglomeration. In some cases, surfactants and / or alcohols can be introduced into the slurry to reduce electrostatic interactions between the fibers. High shear mixing and flow can also help reduce agglomeration / flocculation in some cases.

[0094] In some embodiments, the liquid phase may include, for example, a thermoplastic or thermosetting resin, such as a thermoplastic solution, a thermoplastic melt, a thermosetting resin, a volatile organic compound, water, or oil. Non-limiting examples of thermosetting resins include phenols, epoxies, bismaleimides, cyanate esters, polyimides, and the like. Further non-limiting examples of thermosetting resins include thermosetting alkyds, bismaleimide polymers, bismaleimide triazine polymers, cyanate ester polymers, vinyl ester polymers, benzocyclobutene polymers, diallyl phthalate polymers, epoxies, hydroxymethylfuran polymers, melamine-formaldehyde polymers, phenols, polyesters, benzoxazines, polydienes, polyisocyanates, polyureas, polyurethanes, silicones, liquid crystal elastomers, elastomers, polyimides, triallyl cyanurate polymers, triallyl isocyanurate polymers, and the like. Non-limiting examples of elastomers include silicone rubber, styrene butadiene rubber, and the like. Non-limiting examples of thermoplastic resins include epoxies, polyesters, vinyl esters, polycarbonates, polyamides (e.g., nylon, PA-6, PA-12, etc.), polyphenylene sulfides, polyetherimides, polyetheretherketones, polyetherketones, and the like.Further non-limiting examples of thermoplastic resins include polyimide (PI), polyamide-imide (PAI), polyetheretherketone (PEEK), polyetherketone (PEK), polyphenylsulfone (PPSU), polyethersulfone (PES), polyetherimide (PEI), polysulfone (PSU), polyphenylene sulfide (PPS), polyvinylidene fluoride (PVDF), perfluoroalkoxyalkane (PFA), polytetrafluoroethylene (PTFE ... Polyfluoroethylene (PTFE), polyphenylene sulfide (PPS), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), polyamide 46 (PA46), polyamide 66 (PA66), polyamide 12 (PA12), polyamide 11 (PA11), polyamide 6 (PA6), polyamide 6.6 (PA6.6), polyamide 6.6 / 6 (PA6.6 / 6), amorphous polyamide (PA6-3-T), polyethylene terephthalate (PET), polyphthalamide (PPA), liquid crystal polymer (LCP), polycarbonate (PC), polybutylene terephthalate (PBT), polyoxymethylene (POM), polyphenyl ether (PPE), polymethyl methacrylate (PMMA), polypropylene (PP), polyethylene (PE), high density polyethylene (HDPE), acrylonitrile-styrene-acrylate (ASA), styrene-acrylonitrile (SAN), acrylonitrile-butadiene-styrene (ABS), polybenzimidazole (PBI), polyvinyl chloride (PVC), polyparaphenylene copolymer (PPP), polyacrylonitrile, polyethyleneimine, polyether ketone ether ketone ketone (PEKEKK), ethylene tetrafluoroethylene (ETFE), polychlorotrifluoroethylene (PCTFE), polymethylpentene, etc. Non-limiting examples of ceramic monomers include siloxanes, silazanes, carbosilanes, etc. In some embodiments, combinations of any one or more of the foregoing are also possible, e.g., as copolymers, blends, mixtures, etc. In some cases, one or more of these may be added, e.g., to aid in the homogeneous dispersion of discontinuous fibers within the liquid.Examples of volatile organic compounds include, but are not limited to, isopropanol, butanol, ethanol, acetone, toluene, or xylene.

[0095] Any suitable amount of discontinuous fibers may be present in the slurry or other liquid. For example, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, or at least 80% of the volume of the slurry may be discontinuous fibers. In some cases, 85% or less, 80% or less, 75% or less, 70% or less, 65% or less, 60% or less, 55% or less, 50% or less, 45% or less, 40% or less, 35% or less, 30% or less, 25% or less, 20% or less, 15% or less, or 10% or less may be discontinuous fibers. In some cases, any combination of these is also possible. For example, the slurry or other liquid may include 70%-80%, 75%-85%, 50%-90%, etc. of discontinuous fibers.

[0096] For example, after the slurry or other liquid is prepared, it may be applied to or exposed to a surface, e.g., to form a substrate. Any suitable method may be used to apply the slurry or other liquid to a surface. As non-limiting examples, the liquid may be poured, coated, sprayed, or painted onto the surface, or the surface may be partially or completely immersed in the liquid. The liquid may be used to wet, coat, and / or surround the surface.

[0097] According to one set of embodiments, a magnetic field may be applied to manipulate the discontinuous fibers, either directly or indirectly, as discussed herein. Any suitable magnetic field may be applied. In some cases, the magnetic field is a constant magnetic field. In other cases, the magnetic field may vary in time, for example, the magnetic field may oscillate or vary periodically in amplitude and / or direction to facilitate manipulation of the discontinuous agent. The oscillation may be a sinusoidal wave or another repeating waveform (e.g., a square wave or a sawtooth wave). The frequency may be, for example, at least 0.1 Hz, at least 0.3 Hz, at least 0.5 Hz, at least 1 Hz, at least 3 Hz, at least 5 Hz, at least 10 Hz, at least 30 Hz, at least 50 Hz, at least 100 Hz, at least 300 Hz, at least 500 Hz, etc., and / or 1000 Hz or less, 500 Hz or less, 300 Hz or less, 100 Hz or less, 50 Hz or less, 30 Hz or less, 10 Hz or less, 5 Hz or less, 3 Hz or less, 10 Hz or less, 5 Hz or less, 3 Hz or less, etc. For example, the frequency may be between 1 Hz and 500 Hz, between 10 Hz and 30 Hz, between 50 Hz and 500 Hz, etc. Also, the frequency may be kept substantially constant or, in some cases, the frequency may vary.

[0098] The magnetic field may have any suitable amplitude, whether constant or oscillating. For example, the amplitude may be at least 0.001T, at least 0.003T, at least 0.005T, at least 0.01T, at least 0.03T, at least 0.05T, at least 0.1T, at least 0.3T, at least 0.5T, at least 1T, at least 3T, at least 5T, at least 10T, etc. In some cases, the amplitude may be 20T or less, 10T or less, 5T or less, 3T or less, 1T or less, 0.5T or less, 0.3T or less, 0.1T or less, 0.05T or less, 0.03T or less, 0.01T or less, 0.005T or less, 0.003T or less, etc. Also, the amplitude may be within any combination of these values. For example, the amplitude may be 0.01T to 10T, 1T to 3T, 0.5T to 1T, etc. The amplitude may be substantially constant or, in some embodiments, may vary, for example, within any range of these values.

[0099] In some embodiments, the magnetic field direction (i.e., the direction of maximum amplitude) may vary by ±90°, ±85°, ±80°, ±75°, ±70°, ±65°, ±60°, ±55°, ±50°, ±45°, ±40°, ±35°, ±30°, ±25°, ±20°, ±15°, ±10°, ±5° relative to the average direction.

[0100] A variety of different devices are commercially available for generating a suitable magnetic field, including permanent magnets or electromagnets. In some cases, oscillating magnetism may be generated by attaching a magnet to a rotating disk and rotating the disk at a suitable speed or frequency. Non-limiting examples of permanent magnets include iron magnets, alnico magnets, rare earth magnets, and the like.

[0101] In one set of embodiments, shear flow may be used to align or manipulate the discontinuous fibers. For example, a shear fluid may be applied to the substrate to align at least a portion of the discontinuous agents, for example, in the direction of the shear flow. Examples of shear fluids that may be used include water or another liquid, such as oil, alcohol, such as ethanol, organic solvents (e.g., isopropanol, butanol, ethanol, acetone, toluene, or xylene, etc.). In some embodiments, the shear fluid may have a viscosity of at least 1 cP. Additionally, in some cases, the shear fluid may be a gas, such as air. The linear flow rate of the shear fluid may be, for example, at least 10 mm / min, at least 20 mm / min, at least 30 mm / min, at least 50 mm / min, at least 100 mm / min, at least 200 mm / min, at least 300 mm / min, etc.

[0102] For example, in one set of embodiments, the fibers may be added to a liquid that includes an alcohol, a solvent, or a resin to form a slurry. The slurry may in some cases be flowed to align the fibers, e.g., the slurry is used as a shear fluid. However, in other cases, the slurry may first be applied to a substrate and then a shear fluid may be used to align the fibers.

[0103] Additionally, in some embodiments, mechanical vibration may be used to manipulate discontinuous fibers, for example, in addition to and / or instead of magnetic manipulation and / or shear flow. For example, mechanical vibration may be used to move discontinuous fibers into or onto a substrate, for example into holes or cavities in the substrate, and / or to substantially align at least discontinuous agents in the substrate, for example, as discussed herein. In one set of embodiments, mechanical vibration may be applied to cause motion of discontinuous fibers of at least 1 μm, at least 2 μm, at least 3 μm, at least 5 μm, at least 10 μm, at least 20 μm, at least 30 μm, at least 50 μm, at least 100 μm, at least 200 μm, at least 300 μm, at least 500 μm, at least 1,000 μm, at least 2,000 μm, at least 3,000 μm, at least 5,000 μm, or at least 10,000 μm.

[0104] Further, in some cases, the mechanical vibration may vary in time, e.g., the mechanical vibration may vary periodically in amplitude and / or direction, e.g., to facilitate manipulation of discontinuous fibers. The vibration may be sinusoidal or another repeating waveform (e.g., square wave or sawtooth wave). The frequency may be, e.g., at least 0.1 Hz, at least 0.3 Hz, at least 0.5 Hz, at least 1 Hz, at least 3 Hz, at least 5 Hz, at least 10 Hz, at least 30 Hz, at least 50 Hz, at least 100 Hz, at least 300 Hz, at least 500 Hz, etc., and / or 1000 Hz or less, 500 Hz or less, 300 Hz or less, 100 Hz or less, 50 Hz or less, 30 Hz or less, 10 Hz or less, 5 Hz or less, 3 Hz or less, etc. For example, the frequency may be 1 Hz to 500 Hz, 10 Hz to 30 Hz, 50 Hz to Hz, etc. Also, the frequency may be kept substantially constant, or in some cases the frequency may be varied. When applied simultaneously with an oscillating magnetic field, their frequencies may independently be the same or different.

[0105] During and / or after alignment, the discontinuous fibers may be positioned or fixed in some embodiments, for example to prevent or limit subsequent movement of the discontinuous fibers in one set of embodiments. Non-limiting examples of techniques include, but are not limited to, solidifying, curing, gelling, melting, heating, evaporating, freezing, lyophilizing, or pressurizing a liquid or slurry.

[0106] In some cases, the liquid may contain a relatively volatile solvent, which can be removed by heating and / or evaporation (e.g., waiting a suitable time or allowing the solvent to evaporate in a fume hood or other ventilated area). Non-limiting examples of volatile solvents include isopropanol, butanol, ethanol, acetone, toluene, or xylene. Other examples of methods for removing solvents include vacuum treatment, freeze drying, mechanical shaking, and the like.

[0107] In one set of embodiments, the discontinuous fibers may be heated, for example, to dry the liquid or remove some of the solvent. For example, the discontinuous fibers may be heated to a temperature of at least about 30° C., at least about 35° C., at least about 40° C., at least about 45° C., at least about 50° C., at least about 55° C., at least about 60° C., at least about 65° C., at least about 70° C., at least about 75° C., at least about 80° C., at least about 90° C., at least about 100° C., at least about 125° C., at least about 150° C., at least about 175° C., at least about 200° C., at least about 250° C., at least about 300° C., at least about 350° C., at least about 400° C., at least about 450° C., at least about 500° C., etc. Any suitable method of heating may be used, for example, a thermoelectric converter, an ohmic heater, a Peltier element, a combustion heater, etc. In some cases, the viscosity of the liquid may be reduced as a result of heating. Heating may occur, for example, before, simultaneously with, or after application of a magnetic field and / or mechanical vibration.

[0108] Thus, in one set of embodiments, a first coating may be applied onto the plurality of discontinuous fibers, which may be substantially aligned as discussed herein. The first coating may be applied onto at least one surface, or internal flat surface, of the plurality of discontinuous fibers, as a coating and / or film. The coating may include, for example, a phase change material, a polymer, etc., as discussed herein. In some cases, the coating may include a filler, for example, a ceramic, a metal, etc., as described herein. The coating may be applied to the plurality of discontinuous fibers, for example, using gravity, capillary action, heat, pressure, etc., as discussed herein.

[0109] Additionally, in some embodiments, a second coating may be applied to at least one surface of the composition, e.g., coating and / or film. The second coating material may comprise the same material as the base coat (first) coating, or may comprise a different material. The coating may be applied using, for example, gravity, capillary action, heat, pressure, etc., and may use the same or different techniques, as discussed herein.

[0110] Additionally, in some embodiments, materials such as phase change materials or other materials as discussed herein may be added to the discontinuous fibers. The materials may be applied at any suitable time, e.g., before, during, and / or after the formation of the discontinuous fibers, or before, during, or after the alignment of the discontinuous fibers, e.g., to form a substrate. The materials may be applied as liquids in some cases and may be cured after application to the discontinuous fibers. In some cases, the materials are allowed to penetrate at least a portion of the discontinuous fibers. Non-limiting examples of penetration techniques include using gravity and capillary forces, applying pressure to the material to force it to penetrate the discontinuous fibers, and the like. In some embodiments, heat may be applied. Other examples include, but are not limited to, heat pressing, calendaring, vacuum infusion, and the like. However, in some cases, the materials are used to cover all or only a portion of the discontinuous fibers, and do not necessarily require, e.g., to completely penetrate or embed the discontinuous fibers within the material (although this may be achieved in yet other embodiments). For example, in some embodiments, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90% of the length of the discontinuous fibers may not be in contact with the phase change material.

[0111] In some cases, pressure may be used to remove some of the liquid from the discontinuous fibers. Examples include, but are not limited to, heat pressing, calendaring, vacuum infusion, etc. The applied pressure may be, for example, at least 15 psi (gauge), at least 30 psi, at least 45 psi, etc. (1 psi = 6895 Pa).

[0112] In some embodiments, heat may be applied to facilitate application of the material. This may be useful, for example, to partially or completely liquefy or soften the material, or to promote its flow or penetration, for example, to surround discontinuous fibers. For example, in one set of embodiments, the material may be heated to a temperature of at least 30° C., at least 40° C., at least 50° C., at least 60° C., at least 70° C., at least 80° C., at least 90° C., etc.

[0113] In one aspect, compositions such as those discussed herein may be used to transfer heat between a first location (e.g., a heat source) and a second location (e.g., a heat sink or a cooling device). The heat source may be any suitable heat source. For example, in one embodiment, the heat source may be a semiconductor device, for example, for use in a computer or other electronic device. The semiconductor device may be, for example, a CPU, a GPU, a RAM module, a power transistor, a laser, a light emitting diode, a photovoltaic cell, etc. In some embodiments, other heat sources may also be used. For example, in one embodiment, the heat source may include a chemical reaction or an electrical system (e.g., resistive heating).

[0114] A heat sink or cooling device may be any device capable of dissipating heat. As a non-limiting example, a heat sink may include a fluid medium, such as air or liquid. For example, a heat sink may include a fan that blows air to cool the device or a pump that applies a liquid coolant. In some cases, a heat sink may include a number of fins through which a fluid can pass, thereby allowing heat transfer to the fluid within the heat sink. The fins may have any shape, such as, for example, pin-shaped, straight, flared, angled, etc. The fins may have any suitable cross-section, such as cylindrical, elliptical, square, etc.

[0115] The heat sink, in some embodiments, may include materials such as copper, aluminum, zinc, magnesium, nickel, or other metals that have relatively high thermal conductivity. In some cases, alloys or mixtures of these and / or other metals are also possible. Additionally, the metals may be solid or, in some embodiments, porous.

[0116] Additionally, in some embodiments, the heat sink may include a ceramic. For example, the ceramic may include materials such as boron nitride, titanium diboride, aluminum nitride, silicon nitride, silicon carbide, graphite, aluminum oxide, magnesium oxide, zinc oxide, beryllium oxide, antimony oxide, silicon oxide, and the like. Combinations of these and / or other materials are also possible. Additionally, the ceramic may be solid or, in some embodiments, porous.

[0117] As discussed herein, the composition may be used to aid in thermal conduction between a first location and a second location. The composition may be placed in direct physical contact with one or both of the heat source and the cooling device, and / or there may be other materials that help facilitate the transport of heat from the heat source to the cooling device. Non-limiting examples include thermal tape (e.g., polyimide, graphite, aluminum, etc.), epoxy, grease, solder, silicone coated fabric, or other thermal interface materials.

[0118] The following documents are incorporated by reference in their entireties: International Patent Publication No. 2018 / 175134, entitled "Fiber-Reinforced Composites, Methods Therefore And Articles Comprising The Same; International Patent Publication No. 2021 / 123334, entitled "Systems and Methods for Carbon Fiber Alignment and Fiber-Reinforced Composites; International Patent Publication No. 2020 / 007381, entitled "Systems and Methods for Forming Short-Fiber Films, Composites Comprising Thermosets and Other Composites; and International Patent Publication No. 2021 / 007389, entitled "Compositions and Methods for Carbon Fiber-Metal Composites." Additionally, U.S. Provisional Patent Application No. 63 / 314,808, filed February 28, 2022, and entitled "Thermally Conductive Aligned Materials and Methods of Making and Use Thereof," is also incorporated by reference in its entirety herein. EXAMPLES

[0119] The following examples are intended to illustrate some embodiments of the present disclosure, but do not exemplify the full scope of the disclosure.

[0120] Example 1 A sample composition according to one embodiment is shown in FIG. 1. The sample in this example was made by coating a Z-axis carbon fiber film (see, e.g., International Patent Publication No. WO 2021 / 007381, incorporated herein by reference) with an aqueous slurry of boron nitride nanoparticles. The water evaporates, leaving a dense coating of boron nitride on one side of the Z-axis fiber film. The Z-axis carbon fiber film in this example was formed by using pitch-based carbon fibers with a longitudinal thermal conductivity of 900 W / m·K. The Z-axis fiber film had a basis weight of 120 g / m 2 It is.

[0121] Example 2 This example illustrates a composition having vertically aligned carbon fibers with a fiber volume fraction of 50% embedded in paraffin wax. The composition is coated with a phase change compound comprised of paraffin wax and a thermally conductive filler. The coating is 76 μm thick and is disposed on the top surface of the composition. When tested according to ASTM D5470, the thermal impedance (RA) of this composition was 0.033 K·in at 50 psi (345 kPa). 2 / W(0.213K cm 2 The SEM of this composition is shown in FIG.

[0122] Example 3 This example shows a composition having vertically aligned carbon fibers with a fiber packing efficiency of 50% coated with a paraffin wax film. When this composition is heated to 60°C, the viscosity of the paraffin wax becomes low enough to penetrate the vertically aligned carbon fibers. When tested according to ASTM D5470, this composition has a thermal impedance (RA) of 0.053 K in at 50 psi (345 kPa). 2 / W(0.342K cm 2 3 shows the SEM image of this composition, and FIG. 4 shows the thickness and thermal impedance of this composition.

[0123] Example 4 In this prophetic example, a central processing unit (CPU) of a laptop personal computer is cooled using one embodiment. The cooling device in this example is a copper vapor chamber. An aligned carbon fiber composition with paraffin wax and a fiber volume fraction of 50% is created, the carbon fibers are pitch-based, and have a thermal conductivity along the long axis of 900 W / m·K. This composition is used to attach a copper vapor chamber to the CPU unit, which allows heat to be transferred from the CPU to the copper vapor chamber.

[0124] Example 5 In this hypothetical example, a graphics processing unit (GPU) for an autonomous vehicle is cooled using one embodiment. The cooling device in this example is an air-cooled aluminum fin heat exchanger. An aligned carbon fiber composition with paraffin wax is fabricated with a fiber volume fraction of 50%, where the carbon fibers are pitch-based and have a thermal conductivity along the long axis of 900 W / m·K. The bulk thermal conductivity of this composition is 60 W / m·K through the thickness and 2 W / m·K in the in-plane direction. This composition is used to attach the aluminum fin heat exchanger to the GPU unit, thereby transferring heat from the GPU to the heat exchanger.

[0125] Example 6 In this hypothetical example, lithium ion batteries in a battery pack are cooled using one embodiment. The cooling device in this example is a cold plate (or cold plate). An aligned carbon fiber composition is made with 50% fiber volume fraction with paraffin wax, where the carbon fibers are pitch-based and have a thermal conductivity along the long axis of 900 W / m·K. The composition has a bulk thermal conductivity of 30 W / m·K through the thickness and 1 W / m·K in the in-plane direction. The composition is used to attach a cold plate to a battery pack, thereby conducting heat from the batteries to the cold plate. The paraffin wax in the composition undergoes an endothermic phase change at 50° C., consuming a portion of the heat flux generated by the lithium ion batteries.

[0126] Although several embodiments of the present disclosure have been described and illustrated herein, one of ordinary skill in the art can readily envision various other means and / or structures for obtaining one or more of the functions and / or results and / or advantages described herein, and each such variation and / or improvement is deemed to be within the scope of the present disclosure. More generally, one of ordinary skill in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary, and that the actual parameters, dimensions, materials, and / or configurations will depend on the particular application for which the teachings of the present disclosure are used. One of ordinary skill in the art will recognize or be able to ascertain, using no more than routine experimentation, many equivalents to the several embodiments of the present disclosure described herein. Thus, the foregoing embodiments are presented by way of example only, and it should be understood that within the scope of the appended claims and equivalents thereof, the present disclosure can be practiced otherwise than as specifically described and claimed. The present disclosure relates to each individual feature, system, article, material, kit, and / or method described herein. In addition, combinations of two or more such features, systems, articles, materials, kits, and / or methods are encompassed within the scope of the present disclosure, if such features, systems, articles, materials, kits, and / or methods are not mutually inconsistent.

[0127] In the event that the present specification and a document incorporated by reference include conflicting and / or inconsistent disclosure, the present specification shall control. In the event that two or more documents incorporated by reference include conflicting and / or inconsistent disclosure with respect to each other, the document having the later effective date shall control.

[0128] All definitions and as used herein should be understood to take precedence over dictionary definitions, definitions in documents incorporated by reference, and / or ordinary meanings of the defined terms.

[0129] The indefinite articles "a" and "an," as used herein and in the claims, unless clearly indicated otherwise, should be understood to mean "at least one."

[0130] The term "and / or" as used in the present specification and claims should be understood to mean "either or both" of conjugated elements, i.e., elements that are present in conjunction in some cases and present separately in others. Unless expressly indicated, other elements may optionally be present other than the elements specifically identified by the "and / or" clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, "A and / or B," when used in conjunction with an open-ended term such as "comprising," means, in one embodiment, A without B (optionally including elements other than B); in another embodiment, B without A (optionally including elements other than A); in yet another embodiment, both A and B (optionally including other elements); and so forth.

[0131] As used in the specification and claims, "or" should be understood to have the same meaning as "and / or" as defined above. For example, when separating items in a list, "or" or "and / or" is inclusive, i.e., It should be construed to include at least one, including more than one, of a number or list of elements, and optionally additional unlisted items. Only explicitly stated items, such as "only one of" or "exactly one of," or when used in the claims, "consisting of," means including exactly one of a number or list of elements. In general, the term "or" as used herein will only be construed as indicating exclusive alternatives (i.e., "either, or the other but not both") when preceded by a term of exclusivity, such as "either," "one of," "only one of," or "exactly one of."

[0132] As used in the specification and claims, the phrase "at least one" in reference to a list of one or more elements should be understood to mean at least one element selected from one or more elements in the list of elements, but not necessarily including at least one of each element specifically listed in the list of elements, and not necessarily excluding combinations of elements in the list of elements. This definition also allows for elements to be optionally present other than elements specifically identified in the list of elements, meaning related or unrelated to those elements specifically identified. Thus, as a non-limiting example, "at least one of A and B" (equivalently, "at least one of A or B," or, equivalently, "at least one of A and / or B") can mean, in one embodiment, at least one, including optionally more than one, A (optionally including elements other than B) in the absence of B; in another embodiment, at least one, including optionally more than one, B (optionally including elements other than A) in the absence of A; in yet another embodiment, at least one, including optionally more than one, A and at least one, including optionally more than one, B (optionally including other elements); etc.

[0133] When the word "about" is used in this specification in connection with a number, further embodiments of the present disclosure should be understood to include that number unmodified by the presence of the word "about."

[0134] Also, unless expressly indicated to the contrary, in any claimed method including one or more steps or acts, the order of the method steps or acts should not be understood as necessarily limited to the order in which the method steps or acts are recited.

[0135] Throughout the claims as well as in the specification, all transitional phrases such as "comprising," "including," "carrying," "having," "containing," "involving," "holding," and the like, are intended to be open-ended, i.e., to mean without limitation. Only the transitional phrases "consisting of" and "consisting essentially of" are closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03. [Explanation of symbols]

[0136] 10 … Cooling device 20 … heat source 30…composition 31 … Base material 32 … Phase change materials 50 … Device

Claims

1. a plurality of discontinuous fibers defining a substrate, at least 30 volume percent of the fibers within the substrate being substantially aligned; and a phase change material in contact with at least a portion of the discontinuous fibers, the phase change material exhibiting a phase change between 0° C. and 80° C. A composition comprising:

2. The composition of claim 1 , wherein the phase change material covers at least a first side of a substrate.

3. The composition of claim 1 or 2, wherein the phase change material surrounds a first side of a substrate.

4. The composition of any one of claims 1 to 3, wherein the phase change material exhibits a phase change between 40°C and 80°C.

5. The composition of any one of claims 1 to 4, wherein the phase change material exhibits a phase change between 50°C and 70°C.

6. The composition of any one of claims 1 to 5, wherein the phase change material comprises a wax.

7. The composition of claim 6 , wherein the wax comprises paraffin wax.

8. 8. The composition of claim 6, wherein the wax comprises a polyethylene wax.

9. The composition of any one of claims 6 to 8, wherein the wax comprises a hydrocarbon wax.

10. The composition of any one of claims 1 to 9, wherein the phase change material comprises silicone.

11. The composition of any preceding claim, wherein the phase change material comprises an acrylic.

12. The composition of any one of claims 1 to 11, wherein the phase change material comprises a thermoplastic resin.

13. The composition of any preceding claim, wherein the phase change material comprises a salt hydrate.

14. 14. The composition of claim 13, wherein the salt hydrate comprises one or more of potassium fluoride tetrahydrate, manganese nitrate hexahydrate, calcium chloride hexahydrate, calcium bromide hexahydrate, lithium nitrate hexahydrate, sodium sulfate decahydrate, sodium carbonate decahydrate, sodium orthophosphate dodecahydrate, and / or zinc nitrate hexahydrate.

15. The composition of any one of claims 1 to 14, wherein the phase change material comprises sodium sulfate decahydrate.

16. The phase change material is NaCl.Na ２ SO ４ ・10H ２ The composition according to any one of claims 1 to 15, comprising O.

17. The composition of any one of claims 1 to 16, wherein the phase change material comprises lauric acid.

18. The composition of any preceding claim, wherein the phase change material comprises trimethylolethane.

19. The composition of any preceding claim, wherein the phase change material comprises lithium nitrate.

20. The composition of any preceding claim, wherein the phase change material comprises manganese nitrate.

21. The composition of any preceding claim, wherein the phase change material comprises manganese chloride.

22. The composition of any preceding claim, wherein the phase change material comprises a eutectic.

23. 23. The composition of claim 22, wherein the eutectic comprises myristic acid and stearic acid.

24. The eutectic is Mg(NO ３ ) ２ ・6H ２ 24. The composition of claim 22 or 23, comprising O and glutaric acid.

25. The composition of any one of claims 22 to 24, wherein the eutectic comprises ethylene glycol distearate.

26. The composition of any one of claims 22 to 25, wherein the eutectic comprises an organic-organic eutectic.

27. The composition of any one of claims 22 to 26, wherein the eutectic comprises an organic-inorganic eutectic.

28. The composition of any one of claims 1 to 27, wherein the phase change material has a viscosity of less than 500 cP at a temperature of 60°C.

29. The composition of any one of claims 1 to 28, wherein the phase change material has a viscosity of less than 100 cP at a temperature of 60°C.

30. The composition of any one of claims 1 to 29, wherein at least 50% by volume of the fibers within the substrate are substantially aligned.

31. The composition of any one of claims 1 to 30, wherein at least 80% by volume of the fibers within the substrate are substantially aligned.

32. The composition of any one of claims 1 to 31, wherein at least 50% of the discontinuous fibers have an alignment that is within 20° of the average alignment of a plurality of discontinuous fibers.

33. The composition of any one of claims 1 to 32, wherein at least 50% of the discontinuous fibers have an alignment within 10° of the average alignment of a plurality of discontinuous fibers.

34. The composition of any one of claims 1 to 33, wherein at least 50% of the discontinuous fibers have an alignment within 5° of the average alignment of a plurality of discontinuous fibers.

35. The composition of any one of claims 1 to 34, wherein the substrate comprises a thermoplastic resin.

36. The composition of any one of claims 1 to 35, wherein the substrate comprises a thermosetting resin.

37. The substrate is selected from the group consisting of polyimide (PI), polyamide-imide (PAI), polyetheretherketone (PEEK), polyetherketone (PEK), polyphenylsulfone (PPSU), polyethersulfone (PES), polyetherimide (PEI), polysulfone (PSU), polyphenylene sulfide (PPS), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), polyamide 46 (PA46), polyamide 66 (PA66), polyamide 12 (PA12), polyamide 11 (PA11), polyamide 6 (PA6), polyamide 6.6 (PA6.6), polyamide 6.6 / 6 (PA6.6 / 6), amorphous polyamide (PA6-3-T), polyethylene terephthalate (PET), polyphthalamide (PPA), liquid crystal polymer (LCP), polycarbonate (P 37. The composition of any one of claims 1 to 36, comprising one or more of the following: polybutylene terephthalate (PBT), polyoxymethylene (POM), polyphenylether (PPE), polymethylmethacrylate (PMMA), polypropylene (PP), polyethylene (PE), high density polyethylene (HDPE), acrylonitrile styrene acrylate (ASA), styrene acrylonitrile (SAN), acrylonitrile butadiene styrene (ABS), polybenzimidazole (PBI), polyvinyl chloride (PVC), polyparaphenylene copolymer (PPP), polyacrylonitrile, polyethyleneimine, polyetherketone etherketone ketone (PEKEKK), ethylene tetrafluoroethylene (ETFE), polychlorotrifluoroethylene (PCTFE), and / or polymethylpentene (PMP).

38. The composition of any one of claims 1 to 37, wherein the substrate comprises a plurality of continuous fibers.

39. The composition of any one of claims 1 to 38, wherein the substrate further comprises fused particles.

40. The composition of any one of claims 1 to 39, wherein the substrate comprises a ceramic.

41. The composition of any one of claims 1 to 40, wherein the substrate comprises boron nitride.

42. The composition of any one of claims 1 to 41, wherein the substrate comprises alumina.

43. The composition of any one of claims 1 to 42, wherein the substrate comprises titania.

44. The composition of any one of claims 1 to 43, wherein the substrate comprises a metal.

45. 45. The composition of claim 44, wherein the metal comprises aluminum.

46. 46. ​​The composition of any one of claims 44 or 45, wherein the metal comprises copper.

47. The composition of any one of claims 44 to 46, wherein the metal comprises silver.

48. The composition of any one of claims 44 to 47, wherein the metal comprises tin.

49. The composition of any one of claims 44 to 48, wherein the metal comprises gold.

50. The composition of any one of claims 1 to 49, wherein the discontinuous fibers comprise carbon fibers.

51. 51. The composition of claim 50, wherein the carbon fibers have a carbon content greater than 94% and a modulus of elasticity of at least 200 GPa.

52. The composition of any one of claims 1 to 51, wherein the discontinuous fibers comprise a polymer.

53. 53. The composition of any one of the preceding claims, wherein the discontinuous fibers comprise one or more of basalt, silicon carbide, aramid, zirconia, nylon, boron, alumina, silica, borosilicate, and / or mullite.

54. The composition of any one of claims 1 to 53, wherein the discontinuous fibers comprise natural fibers.

55. The composition of any one of claims 1 to 54, wherein the discontinuous fibers have an average length of at least 20 μm.

56. 56. The composition of any one of the preceding claims, wherein the discontinuous fibers have an average aspect ratio of length to diameter that is at least 5.

57. The composition of any one of the preceding claims, wherein at least a portion of the discontinuous fibers are coated with a coating.

58. 58. The composition of claim 57, wherein the coating comprises a surfactant, a silane coupling agent, an epoxy, a glycerin, a polyurethane, and / or an organometallic coupling agent.

59. The composition of any one of claims 1 to 58, wherein at least a portion of the discontinuous fibers are coated with a sizing agent.

60. 60. The composition of any one of claims 1 to 59, wherein at least a portion of the discontinuous fibers exhibit a physical response to a magnetic field strength of 10 T.

61. The composition of any one of claims 1 to 60, wherein at least a portion of the plurality of discontinuous fibers have a plurality of magnetic particles adsorbed thereto.

62. The composition of any one of claims 1 to 61, wherein the plurality of discontinuous fibers does not include magnetic particles.

63. The composition of any one of claims 1 to 62, wherein the composition is substantially free of paramagnetic or ferromagnetic materials.

64. The composition of any one of claims 1 to 63, wherein at least a portion of the plurality of discontinuous fibers are embedded in a phase change material.

65. 65. The composition of any one of claims 1-64, wherein the plurality of discontinuous fibers have a first end in contact with a phase change material and a second end not in contact with a phase change material.

66. 66. The composition of claim 65, wherein at least 30% of the length of the discontinuous fibers is not in contact with the phase change material.

67. 67. The composition of any one of claims 65 or 66, wherein at least 50% of the length of the discontinuous fibers is not in contact with a phase change material.

68. 68. The composition of any one of claims 65 to 67, wherein at least 70% of the length of the discontinuous fibers is not in contact with the phase change material.

69. The composition has a basis weight of at least 100 g / m ２ The composition according to any one of claims 1 to 68,

70. The composition of any one of claims 1 to 69, wherein the composition has an overall thermal conductivity of at least 5 W / mK.

71. The composition of any one of claims 1 to 70, wherein the composition has an overall thermal conductivity of at least 30 W / mK.

72. The composition of any one of claims 1 to 71, wherein the composition has an overall thermal conductivity of at least 50 W / mK.

73. The composition of any one of claims 1 to 72, wherein the composition has an overall thermal conductivity of at least 100 W / mK.

74. The composition of any one of claims 1 to 73, wherein the composition has an overall thermal conductivity of at least 500 W / mK.

75. The composition of any one of claims 1 to 74, wherein the composition has an overall thermal conductivity of at least 750 W / mK.

76. The composition of any one of claims 1 to 75, wherein the composition exhibits anisotropic thermal conductivity.

77. 77. A device comprising the composition of any one of claims 1 to 76, wherein the composition is in thermal communication with a heat source and a cooling device.

78. a plurality of discontinuous fibers defining a substrate, at least 30 volume percent of the fibers within the substrate being substantially aligned; and A polymer in contact with at least a portion of the discontinuous fibers, the polymer having a viscosity of less than 500 cP at a temperature of 60° C. A composition comprising:

79. 80. The composition of claim 78, wherein the polymer covers at least a first side of a substrate.

80. 80. The composition of any one of claims 78 or 79, wherein the polymeric material surrounds a first side of the substrate.

81. The composition of any one of claims 78 to 80, wherein the polymer has a viscosity of greater than 1 cP at a temperature of 60°C.

82. heat source, Cooling device, Compositions in physical contact with heat sources and cooling devices Including, the composition comprising: (a) a plurality of discontinuous fibers defining a substrate; and (b) a phase change material in contact with at least a portion of the discontinuous fibers; At least 30% by volume of the fibers within the substrate are substantially aligned; The device, wherein the phase change material exhibits a phase change between 0°C and 80°C.

83. 83. The device of claim 82, wherein the phase change material covers at least a first side of a substrate.

84. 84. The device of claim 82 or 83, wherein the phase change material surrounds a first side of a substrate.

85. The device of any one of claims 82 to 84, wherein the heat source is a semiconductor microchip.

86. The device of any one of claims 82 to 85, wherein the cooling device is a cooling fin.

87. The device of any one of claims 82 to 86, wherein the device is a computer.

88. heat source Cooling device, Compositions in physical contact with heat sources and cooling devices Including, The composition comprises: (a) a plurality of discontinuous fibers defining a substrate; and (b) a polymer in contact with at least a portion of the discontinuous fibers; At least 30% by volume of the fibers within the substrate are substantially aligned; The device, wherein the polymer has a viscosity of less than 500 cP at a temperature of 60°C.

89. 90. The device of claim 88, wherein the polymer covers at least a first side of the substrate.

90. 90. The device of any one of claims 88 or 89, wherein the polymer surrounds a first side of the substrate.

91. heat source, Cooling device, Compositions in physical contact with heat sources and cooling devices Including, the composition comprises a plurality of discontinuous fibers defining a substrate; At least 30% by volume of the fibers within the substrate are substantially aligned; The composition has a through-thickness thermal conductivity of at least 5 W / m·K.

92. 92. The device of claim 91, wherein the through-thickness thermal conductivity is at least 30 W / mK.

93. 93. The device of claim 91 or 92, wherein the cooling arrangement comprises a plurality of cooling fins.

94. The device of any one of claims 91 to 93, wherein the composition is disposed between a heat source and a cooling device.

95. heat source, Cooling equipment, and A composition in physical contact with said heat source and said cooling device. Including, The device, wherein the composition exhibits anisotropic thermal conductivity and has a through-thickness thermal conductivity of at least 5 W / m·K.

96. 96. The device of claim 95, wherein the through-thickness thermal conductivity is at least 30 W / mK.

97. 97. The device of any one of claims 95 or 96, wherein the cooling arrangement comprises a plurality of cooling fins.

98. The device of any one of claims 95 to 97, wherein the composition is disposed between the heat source and the cooling device.

99. providing a plurality of discontinuous fibers defining a substrate; and Exposing at least a portion of the discontinuous fibers to a phase change material. Including, At least 30% by volume of the fibers within the substrate are substantially aligned; The method, wherein the phase change material exhibits a phase change between 0° C. and 80° C. and forms a discrete layer on at least one side of the substrate.

100. 100. The method of claim 99, wherein exposing at least a portion of the discontinuous fibers to a phase change material comprises coating at least a first side of a substrate with a phase change material.

101. 101. The method of any one of claims 99 or 100, wherein exposing at least a portion of the discontinuous fibers to a phase change material comprises surrounding a substrate with a phase change material.

102. 102. The method of any one of claims 99 to 101, wherein exposing at least a portion of the discontinuous fibers to a phase change material comprises coating a first side of a substrate with a phase change material.

103. 103. The method of any one of claims 99-102, wherein exposing at least a portion of the discontinuous fibers to a phase change material comprises coating a first side of the substrate with a phase change material but not coating a second side of the substrate with a phase change material.

104. 104. The method of claim 103, further comprising coating a second side of the substrate with a coating material.

105. 105. The method of claim 104, wherein the coating material and the phase change material have different compositions.

106. 106. The method of any one of claims 99 to 105, wherein exposing at least a portion of the discontinuous fibers to a phase change material comprises embedding at least a portion of a substrate in a phase change material.

107. 107. The method of any one of claims 99 to 106, wherein exposing at least a portion of the discontinuous fibers to a phase change material comprises embedding the entire substrate in a phase change material.

108. 108. The method of any one of claims 99 to 107, further comprising applying pressure to the phase change material to cause the phase change material to flow around at least some of the discontinuous fibers.

109. 109. The method of any one of claims 99-108, further comprising using gravity to cause the phase change material to flow around at least some of the discontinuous fibers.

110. 110. The method of any one of claims 99 to 109, further comprising using capillary action to cause the phase change material to flow around at least some of the discontinuous fibers.

111. The method of any one of claims 99 to 110, further comprising contacting the substrate and / or phase change material with a heat source.

112. The method of any one of claims 99 to 111, further comprising contacting the substrate and / or phase change material with a cooling device.

113. providing a plurality of discontinuous fibers defining a substrate; and exposing at least a portion of the discontinuous fibers to a polymer Including, At least 30% by volume of the fibers within the substrate are substantially aligned; The method of claim 1, wherein the polymer has a viscosity of less than 500 cP at a temperature of 60° C.

114. 114. The method of claim 113, wherein exposing at least a portion of the discontinuous fibers to a phase change material comprises coating at least a first side of a substrate with a phase change material.

115. 115. The method of any one of claims 113 or 114, wherein exposing at least a portion of the discontinuous fibers to the phase change material comprises surrounding a substrate with the phase change material.

116. heat source, A cooling device in physical contact with the heat source. Including, the cooling device includes a plurality of discontinuous fibers defining a substrate; At least 30% by volume of the fibers within the substrate are substantially aligned; The device, wherein the composition has a through-thickness thermal conductivity of at least 5 W / m·K.

117. 117. The device of claim 116, wherein the through-thickness thermal conductivity is at least 30 W / mK.

118. heat source, A cooling device that is in physical contact with the heat source Including, The device, wherein the composition exhibits anisotropic thermal conductivity and has a through-thickness thermal conductivity of at least 5 W / m·K.

119. 119. The device of claim 118, wherein the thermal conductivity through the thickness is at least 30 W / mK.

120. a plurality of discontinuous fibers defining a substrate; and A phase change material in contact with at least a portion of the discontinuous fibers. Including, At least 30% by volume of the fibers within the substrate are substantially aligned; A composition, wherein the phase change material exhibits a phase change between 0°C and 300°C.

121. heat source Cooling device, A composition in physical contact with said heat source and said cooling device. Including, the composition comprising: (a) a plurality of discontinuous fibers defining a substrate; and (b) a phase change material in contact with at least a portion of the discontinuous fibers; At least 30% by volume of the fibers within the substrate are substantially aligned; The device, wherein the phase change material exhibits a phase change between 0°C and 300°C.

122. providing a plurality of discontinuous fibers defining a substrate; and Exposing at least a portion of the discontinuous fibers to a phase change material. Including, At least 30% by volume of the fibers within the substrate are substantially aligned; The method, wherein the phase change material exhibits a phase change between 0° C. and 300° C. and forms a discrete layer on at least one side of the substrate.

123. A substrate containing 30% or less by volume of metal; and A phase change material in contact with at least a portion of the discontinuous fibers. Including, The substrate has a thickness of 2.7 g / cm ３ and a thermal conductivity of at least 5 W / m K; A composition, wherein the phase change material exhibits a phase change between 0°C and 300°C.

124. 124. The composition of claim 123, wherein the substrate is metal-free.

125. 125. The composition of claim 123 or 124, wherein at least 50% by volume of the substrate comprises carbon fiber.

126. 126. The composition of claim 125, wherein at least 30% by volume of the fibers within the substrate are substantially aligned.

127. The composition of any one of claims 123 to 126, wherein the substrate has a through-thickness thermal conductivity of at least 5 W / m·K.

128. The composition of any one of claims 123 to 127, wherein the substrate has a through-thickness thermal conductivity of at least 20 W / m·K.

129. The composition of any one of claims 123 to 128, wherein the substrate comprises a metal.

130. The composition of any one of claims 123 to 129, wherein the substrate comprises a ceramic.

131. The composition of any one of claims 123 to 130, wherein the substrate comprises a polymer.

132. 132. The composition of claim 131, wherein the polymer comprises a thermoplastic polymer.

133. 133. The composition of any one of claims 131 or 132, wherein the polymer comprises a thermosetting polymer.

134. The composition of any one of claims 123 to 133, wherein the substrate comprises particles.

135. 135. The composition of claim 134, wherein the particles comprise a metal.

136. 136. The composition of any one of claims 134 or 135, wherein the particles comprise a ceramic.

137. heat source Cooling device, A composition in physical contact with said heat source and said cooling device. Including, the composition comprising: (a) a substrate comprising up to 30 volume percent metal; and (b) a phase change material in contact with at least a portion of the discontinuous fibers; The substrate is 2.7 g / cm ３ and a thermal conductivity of at least 5 W / m K; The device, wherein the phase change material exhibits a phase change between 0°C and 300°C.

138. 138. The device of claim 137, wherein the substrate is metal-free.

139. 139. The device of any one of claims 137 or 138, wherein at least 50% by volume of the substrate comprises carbon fiber.

140. 140. The device of claim 139, wherein at least 30% by volume of the fibers within the substrate are substantially aligned.

141. The device of any one of claims 137 to 140, wherein the substrate has a through-thickness thermal conductivity of at least 5 W / m·K.

142. The device of any one of claims 137 to 141, wherein the substrate has a through-thickness thermal conductivity of at least 20 W / m·K.

143. The device of any one of claims 137 to 142, wherein the substrate comprises a metal.

144. The device of any one of claims 137 to 143, wherein the substrate comprises a ceramic.

145. The device of any one of claims 137 to 144, wherein the substrate comprises a polymer.

146. The device of claim 145, wherein the polymer comprises a thermoplastic polymer.

147. The device of claim 145 or 146, wherein the polymer comprises a thermosetting polymer.

148. The device of any one of claims 137 to 147, wherein the substrate comprises particles.

149. 149. The device of claim 148, wherein the particles comprise a metal.

150. 150. The device of claim 148 or 149, wherein the particles comprise a ceramic.

151. 2.7 g / cm ３ 1. A composition comprising a substrate having a density less than 100 nm and exhibiting a through-thickness anisotropic thermal conductivity of at least 5 W / m·K.

152. 152. The composition of claim 151, wherein at least 50% by volume of the substrate comprises carbon fiber.

153. 153. The composition of claim 152, wherein at least 30% by volume of the fibers within the substrate are substantially aligned.

154. 154. The composition of claims 152 or 153, wherein at least 50% by volume of the fibers within the substrate are substantially aligned.

155. The composition of any one of claims 152 to 154, wherein at least 80% by volume of the fibers within the substrate are substantially aligned.

156. 156. The composition of any one of claims 152-155, wherein at least 50% of the fibers have an alignment that is within 20 degrees of the average alignment of the fibers.

157. The composition of any one of claims 151 to 156, wherein the substrate comprises a metal.

158. The composition of any one of claims 151 to 157, wherein the substrate comprises a ceramic.

159. The composition of any one of claims 151 to 158, wherein the substrate comprises a polymer.

160. 160. The composition of claim 159, wherein the polymer comprises a thermoplastic polymer.

161. 161. The composition of claim 159 or 160, wherein the polymer comprises a thermosetting polymer.

162. The composition of any one of claims 151 to 161, wherein the substrate comprises particles.

163. 163. The composition of claim 162, wherein the particles comprise a metal.

164. 164. The composition of any one of claims 162 or 163, wherein the particles comprise a ceramic.

165. heat source Cooling device, A composition in physical contact with said heat source and said cooling device. Including, the composition comprising: (a) a substrate comprising 30 volume percent or less of particles; and (b) a phase change material in contact with at least a portion of the discontinuous fibers; The substrate is 2.7 g / cm ３ and a thermal conductivity of at least 5 W / m K; The device, wherein the phase change material exhibits a phase change between 0°C and 300°C.

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