Reduced material migration from thermal management and / or electromagnetic interference (EMI) mitigation materials

Abstract

The present disclosure relates to reducing material migration from other polymer-inorganic composites used in thermal management and / or electromagnetic interference (EMI) mitigation materials (e.g., thermal interface materials (TIMs), EMI absorbers, thermally conductive EMI absorbers, electrically conductive elastomers (ECEs), electrically conductive composites, combinations thereof, etc.) and other purposes. In exemplary embodiments, the method includes adding halloysite and / or hollow nanotubular inorganic structures and / or tubular inorganic nanomaterials to the composite in an amount sufficient to reduce material migration from the composite. Also disclosed are exemplary embodiments of composites including halloysite and / or hollow nanotubular inorganic structures and / or tubular inorganic nanomaterials in an amount sufficient to reduce material migration from the composite.

Description

[Technical Field]

[0001] The present disclosure relates to reducing material migration from thermal management and / or electromagnetic interference (EMI) mitigation materials (e.g., thermal interface materials (TIMs), EMI absorbers, thermally conductive EMI absorbers, electrically conductive elastomers (ECEs), electrically conductive composites, combinations thereof, etc.) and other polymer-inorganic composites used for other purposes. [Background technology]

[0002] This section provides background information related to the present disclosure that is not necessarily prior art. Electrical components, such as semiconductors, integrated circuit packages, transistors, and the like, typically have a pre-designed temperature at which they optimally operate. Ideally, the pre-designed temperature is close to the temperature of the surrounding air. However, operation of the electrical components generates heat. If the heat is not removed, the electrical components may operate at temperatures significantly higher than their normal or desired operating temperature. Such excessive temperatures can adversely affect the operating characteristics of the electrical components and the operation of associated devices.

[0003] To avoid or at least mitigate adverse operating characteristics due to heat generation, heat must be removed, for example, by conduction from an operating electrical component to a heat sink. The heat sink can then be cooled by conventional convection and / or radiation techniques. During conduction, heat can be transferred from an operating electrical component to a heat sink by direct surface contact between the electrical component and the heat sink and / or by contact between the electrical component and the heat sink surface through an intermediate medium or thermal interface material (TIM). Thermal interface materials can be used to fill gaps between heat transfer surfaces to increase heat transfer efficiency compared to filling the gap with air, which has a relatively low thermal conductivity.

[0004] Additionally, a common problem in the operation of electronic devices is the generation of electromagnetic radiation within the equipment's electronic circuits. Such radiation can cause electromagnetic interference (EMI) or radio frequency interference (RFI), which can disrupt the operation of other electronic devices within a certain proximity. Without proper shielding, EMI / RFI interference can cause degradation or complete loss of important signals, thereby rendering electronic equipment inefficient or inoperable.

[0005] A common solution to ameliorating the effects of EMI / RFI is to use shields that absorb and / or reflect and / or redirect EMI energy. These shields are typically used to localize EMI / RFI within its source and to isolate other devices near the EMI / RFI source. These shields can be constructed from metals, polymer-inorganic composites, filled foams, foam materials wrapped or coated with absorbing and / or reflective materials, etc.

[0006] The term "EMI," as used herein, should generally be considered to include and refer to EMI and RFI emissions, and the term "electromagnetic" should generally be considered to include and refer to electromagnetic and radio frequencies from external and internal sources. Accordingly, the term shielding (as used herein) broadly includes and refers to reducing (or limiting) EMI and / or RFI so that it does not interfere, such as by attenuating, absorbing, reflecting, blocking, and / or redirecting energy, or some combination thereof, for example, for government compliance and / or the internal functioning of an electronic system.

[0007] When not composed of metal, the mitigation materials often consist of inorganic-polymer or metal-polymer composites. The concentration of inorganic material, usually particles, in the polymer matrix is ​​often high for the purpose of achieving the desired management of thermal and / or EMI issues. In some embodiments, the composite is used in applications where it is compressed between two parts of a device requiring management of thermal and / or EMI issues. This compression can occur during device assembly or during compression and expansion cycles during device use. As a result, the composite must be "soft" so that it can easily deflect and absorb compressive forces without transmitting them to the protected device and risking physical damage. As known to those skilled in the art, in some situations, the methods used to prepare such soft composites result in materials into which various organic species may migrate over time, especially after repeated compression and expansion cycles. These organic species may consist of polymers, monomers, additives used to form the composite or to enhance its performance during use, composites of organic and inorganic materials, etc. The term "oil bleed" is commonly used within the industry to describe this phenomenon, and is used herein with the understanding that "oil" refers to a range of primarily organic species, and "bleed" refers to the migration of material from within the composite to one or more locations outside the composite. [Brief explanation of the drawings]

[0008] The drawings described herein are only for purposes of illustrating selected embodiments, do not depict every possible implementation, and are not intended to limit the scope of the present disclosure. [Figure 1] 1 illustrates an exemplary embodiment in which a first thermal management and / or electromagnetic interference (EMI) mitigation material (e.g., a thermally conductive EMI absorber, etc.) is disposed between the board-level shield and the integrated circuit or chip. FIG. 1 also illustrates a second thermal management and / or electromagnetic interference (EMI) mitigation material (e.g., a thermally conductive pad, other thermal interface material, etc.) between the heat sink and the board-level shield. [Figure 2] An example of a thermal gap filler comprising a ceramic-filled silicone sheet to which halloysite or other tubular nanomaterial / hollow nanotube additive (e.g., imogolite, Saudi halloysite-like nanotubes, etc.) may be added in an amount sufficient to reduce material migration (e.g., silicone oil bleed, etc.) from the thermal gap filler according to exemplary embodiments of the present disclosure (e.g., about 10 wt. % or less, about 5-10 wt. %, about 0.1-2 wt. %, about 1 wt. %) is shown. In such exemplary embodiments, the thermal gap filler containing the halloysite additive may be configured to have high thermal conductivity (e.g., about 4 W / mK or greater), low pressure-to-deflection, and excellent surface wetting for low contact resistance. The thermal gap filler may also minimize or at least reduce stress on substrates and components during assembly. The thermal gap filler may be suitable for high-tolerance applications. The thermal gap filler may also be REACH and ROHS compliant and / or have a UL flammability rating of UL V-0. [Figure 3] 3 includes exemplary properties that a thermal gap filler including a ceramic-filled silicone sheet containing halloysite or other tubular nanomaterial / hollow nanotube additives may have according to exemplary embodiments of the present disclosure. In other exemplary embodiments, the thermal gap filler may be configured differently and may have one or more properties (e.g., thermal conductivity greater than or less than 4 W / mK) different from those shown in FIG. 3. [Figure 4]1 is a line graph illustrating the relationship between deflection modulus and pressure in pounds per square inch (PSI) that a thermal gap filler including a ceramic-filled silicone sheet containing halloysite or other tubular nanomaterial / hollow nanotube additive according to an exemplary embodiment of the present disclosure can have. The five thermal gap filler samples had various sheet thicknesses: 1.0 mm (40 mil), 1.5 mm (60 mil), 3.56 mm (140 mil), 4.57 mm (180 mil), and 5.08 mm (200 mil). The ceramic-filled silicone sheet contained a sufficient amount of halloysite additive to reduce material migration (e.g., silicone oil bleeding) from the thermal gap filler. [Figure 5] 1 is a line graph illustrating the relationship between thermal resistance in degrees Celsius per watt (C-in2 / W) and pressure in pounds per square inch (PSI) that a thermal gap filler including a ceramic-filled silicone sheet containing halloysite or other tubular nanomaterial / hollow nanotube additive according to an exemplary embodiment of the present disclosure may have. The four thermal gap filler samples had various sheet thicknesses: 1.0 mm (40 mil), 1.5 mm (60 mil), 2.0 mm (80 mil), and 2.54 mm (100 mil). The ceramic-filled silicone sheet contained a sufficient amount of halloysite additive to reduce material migration (e.g., silicone oil bleed) from the thermal gap filler. DETAILED DESCRIPTION OF THE INVENTION

[0009] Detailed Description Example embodiments will now be described more fully with reference to the accompanying drawings. Disclosed herein is an innovative method for reducing material migration (e.g., silicone oil bleed, etc.) from thermal management and / or electromagnetic interference (EMI) mitigation materials (e.g., thermal interface materials (TIMs), EMI absorbers, thermally conductive EMI absorbers, electrically conductive elastomers (ECEs), electrically conductive composites, combinations thereof, etc.) and other polymer-inorganic composites used for other purposes.

[0010] Oil-bleed is a concern not only because of potential contamination of optical components in electronic applications (e.g., optical transceivers, camera lenses, etc.), but also for aesthetic reasons. Therefore, it is desirable to reduce and / or prevent material migration, such as silicone oil bleed, from polymer-inorganic composites used to mitigate thermal and / or EMI problems in devices. Furthermore, it is desirable to reduce material migration while minimizing or only slightly changing other desirable properties of the composite.

[0011] However, it is difficult to balance the preparation of highly filled polymer composites for use as thermal management and / or electromagnetic interference (EMI) mitigation materials that can easily deflect under low levels of force while meeting the desired mitigation and other requirements. Oil-bleeding in these materials can occur for several reasons. For example, conventional thermal management and / or electromagnetic interference (EMI) mitigation materials are generally based on the use of silicone polymers. Silicone polymers typically contain polymers with a broad molecular weight (MW) distribution. It is generally believed that some of the polymers with low molecular weights can migrate within the matrix, to the extent that the migrated polymer material is visibly evident beyond the bounds of the composite, thereby resulting in undesirable aesthetics. In addition to silicone polymers, other additives in the composite, such as dispersants, stabilizers (e.g., UV stabilizers, thermal stabilizers, etc.), can also migrate. Composites using polymers not based on silicone materials also contain migratory species and face similar challenges, as discussed above for typical silicone-based systems.

[0012] Having recognized the above, innovative methods have been developed and / or are disclosed herein that solve the problem of how to prepare highly filled polymer composites that have the ability to easily deflect under the application of low levels of force without undesired migration or bleeding of materials from the composite into surrounding areas. It was believed that tubular nanomaterials / hollow nanotubular additives, such as halloysite, imogolite, and Saudi halloysite-like nanotubes, may provide a method for reducing the migration of more mobile materials within a composite by preferentially adsorbing or reacting these materials with the bulk matrix of the composite within the nanotubes without undesired interactions such as hardening. Those skilled in the art will appreciate that these nanomaterials can be subjected to surface modification treatments to make them compatible with various matrices, and that these variations are included within the definition of these materials.

[0013] As disclosed herein, exemplary embodiments include reducing material migration by using halloysite clay as an additive to thermal management and / or electromagnetic interference (EMI) mitigation materials (e.g., thermal interface materials, EMI absorbers, thermally conductive EMI absorbers, electrically conductive elastomers (ECEs), electrically conductive composites, combinations thereof, etc.) and other polymer-inorganic composites used for other purposes. In exemplary embodiments, halloysite is added in an amount sufficient to provide the resulting thermal management and / or electromagnetic interference (EMI) mitigation material with advantageous properties of reduced or no detectable bleeding compared to a thermal management and / or electromagnetic interference (EMI) mitigation material of the same formulation but without halloysite. In some cases, the addition of the clay can also reduce the force required for deflection and improve thixotropy.

[0014] For comparison, an oil-absorbing material was added to the TIM pad formulation. The TIM pad with the oil-absorbing material was then compared with a TIM pad of the same formulation but without the oil-absorbing material. Various oil-absorbing agents added to the TIM pad formulation included talc powder, corn starch, alumina fiber, kaolin clay, and halloysite. It was observed that the talc powder, corn starch, alumina fiber, and kaolin clay absorbents did not perform as well as halloysite. In particular, halloysite significantly reduced oil bleed from the TIM pad while improving the flexural properties of the TIM pad, or at least maintaining substantially the same flexural properties. This observation is particularly noteworthy because kaolin clay and halloysite clay have similar chemical compositions but differ in the physical structure of the clay particles. It was recognized that halloysite's unique nanotube structure potentially allows it to absorb free-flowing polymers that would otherwise separate from the bulk material.

[0015] Compared to a TIM with a halloysite additive, a TIM with the same formulation without the halloysite additive has a significantly greater tendency to bleed. This can lead to aesthetic and performance issues in electronic applications. While conventional methods exist for reducing bleed from TIMs, such conventional methods are often found to significantly increase hardness. As a result, a harder TIM cannot easily flex under the application of low levels of force. Therefore, exemplary embodiments are disclosed herein in which halloysite and / or other tubular nanomaterials / hollow nanotubular additives are added to formulations for thermal management and / or electromagnetic interference (EMI) mitigation materials to reduce bleed and increase flexibility without adversely changing other desired properties of the thermal management and / or electromagnetic interference (EMI) mitigation materials.

[0016] Experimental results showed positive effects of adding 0.2 weight percent (wt%) and 0.5 wt% halloysite to the silicone-based thermal gap filler pad formulation. The addition of 0.5 wt% halloysite to the formulation resulted in a silicone-based thermal gap filler pad that improved to lower deflection forces and reduced bleed to undetectable amounts. Microscopic analysis indicated the presence of halloysite particles within the matrix. In contrast, the addition of 0.5 wt% kaolin to the same silicone-based thermal gap filler pad formulation did not produce the same improvement.

[0017] By way of background, kaolin and halloysite have the same composition but different structures. More specifically, halloysite contains hollow nanotube structures, or tubular nanomaterials, while kaolin is plate-shaped. We speculate that tubular halloysite interacts more effectively with bleed components than plate-shaped kaolin, resulting in surprisingly effective results even when using very small amounts of halloysite additive. Halloysite-class clays are nanotubular, and most of the active hydroxyl groups are located inside the nanotubes. We speculate that the interior of halloysite nanotube material may trap low-molecular-weight (MW) components in formulated products. The lower concentration of active groups on the exterior of halloysite tubular nanoparticles should reduce the amount of undesired crosslinking of matrix polymers.

[0018] Without limiting the scope of the present invention or the claims, it is believed that the ability of halloysite to reduce the migration of organic species is due to the interaction of those species with the aluminol groups within the nanotubes. As a result, the present invention should be broadly applicable to a wide range of compounded products used to control the thermal and electromagnetic properties of materials where migration of organic species within the composite to the exterior of the composite is undesirable.

[0019] Accordingly, the present disclosure relates to reducing material migration (e.g., oil bleed, etc.) from thermal management and / or electromagnetic interference (EMI) mitigation materials (e.g., thermal interface materials (TIMs), EMI absorbers, thermally conductive EMI absorbers, electrically conductive elastomers (ECEs), electrically conductive composites, combinations thereof, etc.) and other polymer-inorganic composites used for other purposes. In exemplary embodiments, the composites include halloysite and / or other hollow nanotubular inorganic structures or tubular inorganic nanomaterials (e.g., imogolite, Saudi halloysite-like nanotubes, etc.) in an amount sufficient to reduce material migration from the composite. The composites may include thermal management and / or electromagnetic interference (EMI) mitigation materials such as thermal interface materials (TIMs), EMI absorbers, thermally conductive EMI absorbers, electrically conductive elastomers (ECEs), electrically conductive composites, or combinations thereof.

[0020] 1 illustrates first and second thermal management and / or electromagnetic interference (EMI) mitigation materials 100, 112 comprising halloysite and / or hollow nanotubular inorganic structures or tubular inorganic nanomaterials (broadly, oil absorbing additives) in an amount sufficient to reduce material migration (e.g., silicone oil bleed, etc.) from the first and second thermal management and / or electromagnetic interference (EMI) mitigation materials 100, 112. As shown, the first thermal management and / or electromagnetic interference (EMI) mitigation material 100 is disposed between a board-level shield 104 and an integrated circuit or chip 108. The second thermal management and / or electromagnetic interference (EMI) mitigation material 112 is disposed between a heat sink 116 and the board-level shield 104.

[0021] The first thermal management and / or electromagnetic interference (EMI) mitigation material 100 may include a thermally conductive EMI absorber operable both as a thermal interface material for establishing a thermally conductive thermal path between the integrated circuit 108 and the board-level shield 104, and as an EMI absorber for inhibiting coupling of radiated electromagnetic fields between the integrated circuit 108 and the heat sink 116. Thus, the first thermal management and / or electromagnetic interference (EMI) mitigation material 100 may provide the combined performance of a thermal interface material and an EMI absorber in a space-saving, dual-purpose, single-product solution.

[0022] As described above, the first thermal management and / or electromagnetic interference (EMI) mitigation material 100 includes halloysite and / or other hollow nanotubular inorganic structures or tubular inorganic nanomaterials (e.g., imogolite, Saudi halloysite-like nanotubes, etc.) in an amount sufficient to reduce material migration (e.g., silicone oil bleed, etc.) from the first thermal management and / or electromagnetic interference (EMI) mitigation material 100. The first thermal management and / or electromagnetic interference (EMI) mitigation material 100 also includes a functional filler (e.g., at least about 25% by weight, at least about 80% by weight, at least about 90% by weight, etc.) in a matrix or base material (e.g., silicone-based polymer resin, non-silicone-based polymer resin, etc.) to increase thermal conductivity and / or for EMI absorption. Examples of functional fillers include carbon black, boron nitride, nickel cobalt, carbonyl iron, iron silicide, iron particles, iron chromium compounds, silver, an alloy containing 85% iron, 9.5% silicon, and 5.5% aluminum, an alloy containing about 20% iron and 80% nickel, ferrites, magnetic alloys, magnetic powders, magnetic flakes, magnetic particles, nickel-based alloys and powders, chromium alloys, oxides, copper, zinc oxide, alumina, graphite, ceramics, silicon carbide, manganese zinc, glass fibers, thermally conductive materials including carbon nanotubes (e.g., single-walled carbon nanotubes, multi-walled carbon nanotubes, etc.), metal composites (e.g., gallium and gallium alloys, etc.) having a melting point near or below room temperature, combinations thereof, and the like.

[0023] In an exemplary embodiment, the first thermal management and / or electromagnetic interference (EMI) mitigation material 100 comprises less than about 10 weight percent matrix or base material, about 1 weight percent or less halloysite nanotubes, and at least about 90 weight percent functional filler. In other exemplary embodiments, the first thermal management and / or electromagnetic interference (EMI) mitigation material 100 may comprise different weight percents of halloysite nanotubes or other hollow nanotubular inorganic structures or tubular inorganic nanomaterials, such as about 10 weight percent or less, about 5-10 weight percent, about 0.1-2 weight percent, etc. The first thermal management and / or electromagnetic interference (EMI) mitigation material 100 may also comprise various weight percents of the matrix or base material (e.g., about 7 weight percent, about 8 weight percent, more than 10 weight percent, etc.) and / or various weight percents of the functional filler (e.g., about 25 weight percent or more, at least about 80 weight percent but less than 90 weight percent, more than 90 weight percent, etc.).

[0024] 1, first thermal management and / or electromagnetic interference (EMI) mitigation material 100 includes a thermally conductive, EMI absorbing pad having a rectangular shape. Alternatively, first thermal management and / or electromagnetic interference (EMI) mitigation material 100 may include a thermally conductive, EMI absorbing pad having a different shape, such as a different polygon (e.g., pentagon, triangle).

[0025] The second thermal management and / or electromagnetic interference (EMI) mitigation material 112 may include a thermal interface material (TIM) operable to establish a thermally conductive thermal path between the heat sink 116 and the board-level shield 104. As described above, the second thermal management and / or electromagnetic interference (EMI) mitigation material 112 includes halloysite and / or other hollow nanotubular inorganic structures or tubular inorganic nanomaterials (imogolite, Saudi halloysite-like nanotubes, etc.) in an amount sufficient to reduce material migration (e.g., silicone oil bleed, etc.) from the second thermal management and / or electromagnetic interference (EMI) mitigation material 112. The second thermal management and / or electromagnetic interference (EMI) mitigation material 112 includes a thermally conductive filler (e.g., about 25% by weight or more, at least about 80% by weight, at least about 90% by weight, etc.) in a matrix or base material (e.g., a silicone-based polymer resin, a non-silicone-based polymer resin, etc.). The thermally conductive filler may include one or more of the following thermally conductive materials including alumina, aluminum, zinc oxide, boron nitride, silicon nitride, aluminum nitride, iron, metal oxides, graphite, silver, copper, ceramics, metal composites with melting points near or below room temperature (such as, for example, gallium and gallium alloys), and combinations thereof.

[0026] By way of example only, the second thermal management and / or electromagnetic interference (EMI) mitigation material 112 may include less than about 10 weight percent matrix or base material, about 1 weight percent or less halloysite additive, and at least about 90 weight percent thermally conductive filler. In other exemplary embodiments, the second thermal management and / or electromagnetic interference (EMI) mitigation material 112 may include various weight percents of halloysite nanotubes or other hollow nanotubular inorganic structures or tubular inorganic nanomaterials, such as about 10 weight percent or less, about 5-10 weight percent, about 0.1-2 weight percent, etc. The second thermal management and / or electromagnetic interference (EMI) mitigation material 112 may also include various weight percents of matrix or base material (e.g., about 7 weight percent, about 8 weight percent, more than 10 weight percent, etc.) and / or various weight percents of functional filler (e.g., about 25 weight percent or more, at least about 80 weight percent but less than 90 weight percent, more than 90 weight percent, etc.).

[0027] 1 , the second thermal management and / or electromagnetic interference (EMI) mitigation material 112 includes a thermally conductive pad having a rectangular shape. Alternatively, the second thermal management and / or electromagnetic interference (EMI) mitigation material 112 may include a thermally conductive pad having a different shape, such as a different polygon (e.g., pentagon, triangle, etc.). In alternative embodiments, the second thermal management and / or electromagnetic interference (EMI) mitigation material 112 may include a dispensable material, thermal grease, bulk putty, phase change TIM, etc.

[0028] Disclosed herein are methods for reducing material migration (e.g., silicone oil bleed, etc.) from composites, such as thermal management and / or electromagnetic interference (EMI) mitigation materials (e.g., thermal interface materials (TIMs), EMI absorbers, thermally conductive EMI absorbers, electrically conductive elastomers (ECEs), electrically conductive composites, combinations thereof, etc.) and other polymer-inorganic composites used for other purposes.

[0029] In exemplary embodiments, the method includes adding halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials to the composite in an amount sufficient to reduce material migration from the composite. In such exemplary embodiments, the hollow inorganic nanotubular structures and / or tubular inorganic nanomaterials added to the composite can include halloysite and / or other hollow inorganic nanotubular structures / tubular inorganic nanomaterials, such as imogolite, Saudi halloysite-like nanotubes, etc.

[0030] In an exemplary embodiment, the composite is a polydimethylsiloxane (PDMS)-based polymer-inorganic composite, and the method includes adding halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials to the polydimethylsiloxane (PDMS)-based polymer-inorganic composite.

[0031] In an exemplary embodiment, the composite is a polymer-inorganic composite that is substantially free of siloxane polymers, and the method includes adding halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials to the polymer-inorganic composite that is substantially free of siloxane polymers.

[0032] In an exemplary embodiment, the method further includes adding one or more of a thermally conductive filler, an electrically conductive filler, an electromagnetic wave absorbing filler, a dielectric absorbing filler, and a filler having two or more of the following properties to the composite: thermal conductivity, electrical conductivity, dielectric absorption, and electromagnetic wave absorption. For example, the method may include adding to the composite one or more of carbon black, boron nitride, nickel cobalt, carbonyl iron, iron silicide, iron particles, iron chromium compounds, silver, an alloy containing 85% iron, 9.5% silicon, and 5.5% aluminum, an alloy containing about 20% iron and 80% nickel, ferrite, magnetic alloys, magnetic powders, magnetic flakes, magnetic particles, nickel-based alloys and powders, chromium alloys, oxides, copper, zinc oxide, alumina, graphite, ceramics, silicon carbide, manganese zinc, glass fibers, thermally conductive materials including carbon nanotubes (e.g., single-walled carbon nanotubes, multi-walled carbon nanotubes, etc.), metal composites having a melting point near or below room temperature (e.g., gallium and gallium alloys, etc.), combinations thereof, and the like.

[0033] In an exemplary embodiment, the method includes adding halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials in an amount sufficient to absorb and / or bind non-crosslinked polymers of the composite that may migrate from the composite and / or absorb lightly crosslinked and / or low molecular weight crosslinked polymers and other fluid materials and additives that may migrate from the composite.

[0034] In an exemplary embodiment, the method includes adding halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials to the composite in an amount sufficient to reduce silicone oil bleeding from the composite, thereby substantially or completely preventing the silicone from migrating outside the confines of the composite, rendering the composite usable and allowing it to easily deflect under the application of low levels of force.

[0035] In an exemplary embodiment, the method includes adding halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials to the composite such that the composite comprises up to about 10 weight percent halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials. For example, the composite may comprise about 10 weight percent or less halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials. Alternatively, for example, the composite may comprise about 5-10 weight percent halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials. As a further example, the composite may comprise about 0.1-2 weight percent halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials. As yet another example, the composite may comprise about 1 weight percent halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials.

[0036] In an exemplary embodiment, the composite is a thermal management and / or electromagnetic interference (EMI) mitigation material that can be used to manage the thermal and / or electromagnetic properties of a device or system. In exemplary embodiments, the composite is a thermal interface material, an EMI absorber, a thermally conductive absorber, a conductive elastomer, a conductive composite, or a combination of two or more thereof. For example, the composite can include a thermal interface material that is a thermally conductive pad, a thermally conductive gap filler, a dispensable material, a thermal grease, a bulk putty, or a phase change TIM.

[0037] In an exemplary embodiment, the method includes using a composite to manage thermal and / or electromagnetic properties of a device or system. In an exemplary embodiment, the method includes dispensing a composite onto a surface of a device to manage thermal and / or electromagnetic properties of the device or a system including the device.

[0038] In an exemplary embodiment, the method includes removing a release liner from the composite and placing the composite on a surface of a device to manage thermal and / or electromagnetic properties of the device or a system including the device.

[0039] In exemplary embodiments, the composite includes halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials in an amount sufficient to reduce material migration from the composite. In such exemplary embodiments, the hollow nanotubular inorganic structures and / or tubular inorganic nanomaterials may include halloysite and / or other hollow inorganic nanotubular structures / tubular inorganic nanomaterials, such as imogolite, Saudi halloysite-like nanotubes, and the like.

[0040] In an exemplary embodiment, the composite is a polydimethylsiloxane (PDMS) based polymer-inorganic composite. In an exemplary embodiment, the composite is a polymer-inorganic composite that is substantially free of siloxane polymers.

[0041] In an exemplary embodiment, the composite further includes one or more of a thermally conductive filler, an electrically conductive filler, an electromagnetic wave absorbing filler, a dielectric absorbing filler, and a filler having two or more of the following properties: thermal conductivity, electrical conductivity, dielectric absorption, and electromagnetic wave absorption. For example, the composite may include one or more of carbon black, boron nitride, nickel cobalt, carbonyl iron, iron silicide, iron particles, iron chromium compounds, silver, an alloy containing 85% iron, 9.5% silicon, and 5.5% aluminum, an alloy containing about 20% iron and 80% nickel, ferrites, magnetic alloys, magnetic powders, magnetic flakes, magnetic particles, nickel-based alloys and powders, chromium alloys, oxides, copper, zinc oxide, alumina, graphite, ceramics, silicon carbide, manganese zinc, glass fibers, thermally conductive materials including carbon nanotubes (e.g., single-walled carbon nanotubes, multi-walled carbon nanotubes, and / or nanostructures), metal composites (e.g., gallium and gallium alloys) having a melting point near or below room temperature, combinations thereof, and the like.

[0042] In exemplary embodiments, the halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials are in an amount sufficient to absorb and / or bind non-crosslinked polymers of the composite that may migrate from the composite and / or absorb lightly crosslinked and / or low molecular weight crosslinked polymers and other fluid materials and additives that may migrate from the composite.

[0043] In exemplary embodiments, the halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials are present in an amount sufficient to reduce silicone oil bleeding from the composite, thereby substantially or completely preventing silicone from migrating outside the confines of the composite, allowing the composite to be used and easily deflectable under the application of low levels of force.

[0044] In exemplary embodiments, the composite comprises up to about 10 weight percent halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials. For example, the composite may comprise about 10 weight percent or less halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials. Alternatively, for example, the composite may comprise about 5-10 weight percent halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials. As a further example, the composite may comprise about 0.1-2 weight percent halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials. As yet another example, the composite may comprise about 1 weight percent halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials.

[0045] By way of further example, the composite may include various weight percentages of matrix or base material, such as about 7% by weight, about 8% by weight, about 10% by weight, greater than 10% by weight, etc. Also by way of example, the composite may include various weight percentages of filler, such as about 25% by weight or more, at least about 80% by weight but less than 90% by weight, greater than 90% by weight, etc.

[0046] In exemplary embodiments, the composite is electrically conductive or insulating, thermally conductive or insulating, EMI absorbing, or a combination of any or all of the foregoing properties. In an exemplary embodiment, the composite is configured so that it can be used to manage the thermal and / or electromagnetic properties of a device or system.

[0047] In an exemplary embodiment, the composite is a thermal management and / or electromagnetic interference (EMI) mitigation material. In exemplary embodiments, the composite is a thermal interface material, an EMI absorber, a thermally conductive absorber, a conductive elastomer, a conductive composite, or a combination of two or more thereof.

[0048] In an exemplary embodiment, a device or system includes a composite material disclosed herein, which is used to manage the thermal and / or electromagnetic properties of the device or system.

[0049] In exemplary embodiments, the composite is EMI absorptive and / or conductive, such that the composite can be used to mitigate and / or manage EMI in electronic devices.

[0050] In an exemplary embodiment, an electronic device includes a heat source and a composite material disclosed herein. The composite material is positioned relative to the heat source to establish at least a portion of a thermally conductive heat path from the heat source through the composite material. The halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials in the composite material reduce material migration (e.g., silicone oil bleed, etc.) from the composite material onto the heat source. The composite material may also be configured to be EMI absorbent and / or conductive, such that the composite material is also operable to mitigate and / or manage EMI within the electronic device.

[0051] In an exemplary embodiment, an electronic device includes a heat source, a heat removal / dissipation structure, and a composite material disclosed herein. The composite material is positioned relative to the heat source and the heat removal / dissipation structure to establish at least a portion of a thermally conductive thermal path between the heat source and the heat removal / dissipation structure. The halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials in the composite material reduce material migration (e.g., silicone oil bleed, etc.) from the composite material onto the heat source and the heat removal / dissipation structure. The composite material may also be configured to be EMI absorbent and / or conductive, such that the composite material is also operable to mitigate and / or manage EMI within the electronic device.

[0052] In an exemplary embodiment, an electronic device includes a heat source, a board-level shield, and a composite material disclosed herein. The composite material is positioned relative to the heat source and the board-level shield to establish at least a portion of a thermally conductive thermal path between the heat source and the board-level shield. Halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials in the composite material reduce material migration (e.g., silicone oil bleed, etc.) from the composite material onto the heat source and the board-level shield. The composite material may also be configured to be EMI absorbent and / or conductive, such that the composite material is also operable to mitigate and / or manage EMI within the electronic device.

[0053] In an exemplary embodiment, an electronic device includes a heat source, a board-level shield, a heat removal / dissipation structure, and first and second composites as disclosed herein. The first composite is positioned relative to the heat source and the board-level shield to establish at least a portion of a first thermally conductive thermal path between the heat source and the board-level shield. The halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials in the first composite reduce material migration (e.g., silicone oil bleed, etc.) from the first composite to the heat source and the board-level shield. The second composite is positioned relative to the board-level shield and the heat removal / dissipation structure to establish at least a portion of a second thermally conductive thermal path between the board-level shield and the heat removal / dissipation structure. The halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials in the second composite reduce material migration (e.g., silicone oil bleed, etc.) from the second composite onto the board-level shield and the heat removal / dissipation structure. The first and / or second composites may also be configured to be EMI absorptive and / or conductive, such that the first and / or second composites are also operable to mitigate and / or manage EMI within the electronic device.

[0054] In an exemplary embodiment, an electronic device includes an integrated circuit, a board-level shield, a heat sink, and first and second composites as disclosed herein. The first composite is positioned relative to the integrated circuit and the board-level shield to establish at least a portion of a first thermally conductive thermal path between the integrated circuit and the board-level shield. The halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials in the first composite reduce material migration (e.g., silicone oil bleed, etc.) from the first composite to the integrated circuit and the board-level shield. The second composite is positioned relative to the board-level shield and the heat sink to establish at least a portion of a second thermally conductive thermal path between the board-level shield and the heat sink. The halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials in the second composite reduce material migration (e.g., silicone oil bleed, etc.) from the second composite and reduce material migration (e.g., silicone oil bleed, etc.) from the second composite onto the board-level shield and the heat sink. The first and / or second composites may also be configured to be EMI absorptive and / or conductive, such that the first and / or second composites are also operable to mitigate and / or manage EMI within the electronic device.

[0055] In addition to other tubular nanomaterials / hollow nanotubular additives, such as halloysite and / or imogolite, Saudi halloysite-like nanotubes, etc., for reducing material migration (e.g., silicone oil bleed, etc.), one or more other suitable fillers and / or additives may also be added to the bulk material for other polymer-inorganic composites used for thermal management and / or EMI mitigation materials or other purposes. For example, one or more of functional nanoparticles, electrically conductive fillers, thermally conductive fillers, EMI or microwave absorbing fillers, magnetic fillers, coating fillers, catalysts for controlling cure, coupling agents for increasing filler loading, pigments or dyes for adding color, plasticizers, processing aids, flame retardants, extenders, tackifiers, antioxidants, ultraviolet (UV) stabilizers, thermal stabilizers, combinations thereof, etc. may also be added. The filler may be added and mixed with a bulk material containing a matrix or base material, thereby providing a mixture of the filler, halloysite additive, and matrix or base material. Exemplary fillers include carbon black, boron nitride, nickel-cobalt, carbonyl iron, iron silicide, iron particles, iron-chromium compounds, silver, an alloy containing 85% iron, 9.5% silicon, and 5.5% aluminum, an alloy containing about 20% iron and 80% nickel, ferrite, magnetic alloys, magnetic powders, magnetic flakes, magnetic particles, nickel-based alloys and powders, chromium alloys, oxides, copper, zinc oxide, alumina, graphite, ceramics, silicon carbide, manganese zinc, glass fibers, thermally conductive materials including carbon nanotubes (e.g., single-walled carbon nanotubes, multi-walled carbon nanotubes, and / or nanostructures), metal composites (e.g., gallium and gallium alloys) having melting points near or below room temperature, combinations thereof, etc. The filler may comprise one or more of granules, spheroids, microspheres, ellipsoids, irregular spheroids, strands, flakes, powders, nanotubes, and / or combinations of any or all of these shapes. Additionally, exemplary embodiments may also include different grades (eg, different sizes, different purities, different shapes, etc.) of the same (or different) fillers.

[0056] In an exemplary embodiment in which the composite comprises halloysite nanotubes, the halloysite nanotubes may comprise aluminosilicate clay hollow nanotube structures having a chemical composition of Al2Si2O5(OH)4·nH2O. The aluminosilicate clay hollow nanotube structures may have a wall thickness of about 10-15 atomic aluminosilicate sheets, an outer diameter of about 50-70 nanometers (nm), an inner diameter of about 10-15 nm, and a length of 0.5-10 micrometers (μm).

[0057] In exemplary embodiments, the composite complies with ROHS Directive 2011 / 65 / EU and (EU) 2015 / 863 and / or is REACH compliant as containing less than 0.1 wt.% of substances on the REACH / SVHC candidate list (June 25, 2020). In exemplary embodiments, the composite contains less than 0.01 wt.% cadmium at or below its regulatory threshold, 0.1 wt.% lead at or below its regulatory threshold, 0.1 wt.% mercury at or below its regulatory threshold, 0.1 wt.% hexavalent chromium at or below its regulatory threshold, 0.1 wt.% flame retardants PBB and PBDE (pentabromodiphenyl ether (CAS-No. 32534-81-9), octabromodiphenyl ether (CAS-No. 32536-52-0), and decabromodiphenyl ether (CAS-No. 11-11-1) at or below its regulatory threshold, and 0.1 wt.% hexabromodiphenyl ether (CAS-No. 11-11-1) at or below its regulatory threshold. 63-19-5), bis(2-ethylhexyl) phthalate (DEHP) (CAS-No. 117-81-7) at or below the regulatory threshold of 0.1% by weight, butyl benzyl phthalate (BBP) (CAS-No. 85-68-7) at or below the regulatory threshold of 0.1% by weight, dibutyl phthalate (DBP) (CAS-No. 84-74-2) at or below the regulatory threshold of 0.1% by weight, and diisobutyl phthalate (DIBP) (CAS-No. 84-69-5) at or below the regulatory threshold of 0.1% by weight.

[0058] Exemplary embodiments of the thermal management and / or EMI mitigation materials disclosed herein may be used in a wide range of industries (e.g., automotive, consumer goods, industrial, telecom / datacom, aerospace / defense, etc.) and a wide range of applications (e.g., automotive electronics, automotive advanced driver assistance systems (ADAS), automotive powertrain / electronic control units (ECUs), automotive infotainment, routers, wireless infrastructure, drones / satellites, gaming systems, smart home devices, notebooks / tablets / portable devices, etc.).

[0059] In an exemplary embodiment, a composite including halloysite and / or other hollow nanotubular inorganic structures, or tubular inorganic nanomaterials such as imogolite and Saudi halloysite-like nanotubes, is provided as a thermal gap filler sheet having a thickness ranging from about 0.1 mm to about 10 mm. The thermal gap filler sheet may have a thermal conductivity of at least about 4 Watts per meter per Kelvin (W / mK). The thermal gap filler sheet may be dielectric and not electrically conductive. The thermal gap filler sheet may have a hardness of about 44 Shore 00 or less at 3 seconds. The numerical values ​​provided in this paragraph are merely examples, and other embodiments may be configured differently, such as with different thicknesses, hardnesses greater than or less than about 44 Shore 00 at 3 seconds, and / or thermal conductivities greater than or less than 4 W / mK. In other exemplary embodiments, the composite may have a hardness within a predetermined range (e.g., + / - 10, etc.) of about 80 Shore 00 (e.g., about 80 Shore 00 at 3 seconds, about 70 Shore 00 at 3 seconds, about 60 Shore 00 at 3 seconds, etc.). In yet other exemplary embodiments, the composite (e.g., EMI absorber, etc.) may have a hardness in the Shore A range.

[0060] In exemplary embodiments, composites comprising halloysite and / or other hollow nanotubular inorganic structures or tubular inorganic nanomaterials such as imogolite, Saudi halloysite-like nanotubes, etc. are thermal interface materials (TIMs) such as thermally conductive pads, thermally conductive gap fillers, dispensable materials, thermal greases, bulk putties, and phase change TIMs. In exemplary embodiments, composites comprising halloysite nanotubes or other hollow nanotubular inorganic structures or tubular inorganic nanomaterials are thermal management and / or EMI mitigation materials having relatively high thermal conductivities (e.g., 1 W / mK (watt per meter per Kelvin), 1.1 W / mK, 1.2 W / mK, 2.8 W / mK, 3 W / mK, 3.1 W / mK, 3.8 W / mK, 4 W / mK, 4.7 W / mK, 5 W / mK, 5.4 W / mK, 6 W / mK, 8 W / mK, etc.), which depend on the particular materials used to make the thermal management and / or EMI mitigation material and the loading percentage of thermally conductive fillers, if any. These thermal conductivities are merely examples, and other embodiments may include thermal management and / or EMI mitigation materials having thermal conductivities greater than 8 W / mK, less than 1 W / mK (e.g., at least about 0.3 W / mK), or values ​​within the range of 1 W / mK to 8 W / mK.

[0061] In exemplary embodiments, thermal management and / or EMI mitigation materials (e.g., thermal interface materials, thermally conductive EMI absorbers, etc.) comprising halloysite and / or other hollow nanotubular inorganic structures or tubular inorganic nanomaterials can be used to define or provide a portion of a thermally conductive thermal path from a heat source to a heat removal / dissipation structure or component. The thermal management and / or EMI mitigation materials can be used, for example, to help conduct thermal energy (e.g., heat, etc.) from a heat source in an electronic device. The thermal management and / or EMI mitigation materials can typically be positioned between a heat source and a heat removal / dissipation structure or component (e.g., in direct physical contact, thermal contact, etc.) to establish a thermal junction, interface, pathway, or thermally conductive thermal path by which heat can be transferred (e.g., conducted) from the heat source to the heat removal / dissipation structure or component. During operation, the thermal management and / or EMI mitigation materials can function to enable the transfer of heat (e.g., conduction of heat, etc.) from the heat source to the heat removal / dissipation structure or component along a thermal conduction path. In exemplary embodiments, the thermal management and / or EMI mitigation material may also be operable to mitigate (eg, absorb) EMI incident on the thermal management and / or EMI mitigation material.

[0062] Exemplary embodiments disclosed herein may be used with a wide range of heat sources, electronic devices, and / or heat removal / dissipation structures or components (e.g., heat spreaders, heat sinks, heat pipes, vapor chambers, external device cases, housings, or chassis, etc.) For example, a heat source may include one or more heat-generating components or devices, such as high-power integrated circuits (ICs), optical transceivers, 5G infrastructure devices (e.g., base stations, small cells, smart poles, etc.), memory in video cards, set-top boxes, televisions, gaming systems, automotive electronics used in autonomous driving (ADAS) (e.g., radar, multi-domain controllers, cameras, etc.), CPUs, die-in-underfill, semiconductor devices, flip-chip devices, graphics processing units (GPUs), digital signal processors (DSPs), multiprocessor systems, integrated circuits (ICs), multi-core processors, etc. Generally, a heat source may include any component or device that has a higher temperature than the thermal management and / or EMI mitigation material or that transfers heat to the thermal management and / or EMI mitigation material, whether the heat is generated by the heat source or simply transferred through or via the heat source. Thus, embodiments of the present disclosure should not be limited to use with a single type of heat source, electronic device, heat removal / dissipation structure, or the like.

[0063] The exemplary embodiments are provided so that this disclosure will be thorough and will fully convey the scope to those skilled in the art. Numerous specific details are set forth, such as examples of specific components, devices, and methods, to provide a thorough understanding of the embodiments of the present disclosure. It will be apparent to those skilled in the art that the use of specific details is not necessary, that the exemplary embodiments can be embodied in many different forms, and that neither should be construed as limiting the scope of the present disclosure. In some exemplary embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail. Furthermore, advantages and improvements that may be achieved in one or more exemplary embodiments of the present disclosure are provided for illustrative purposes only and do not limit the scope of the present disclosure, as an exemplary embodiment of the present disclosure may provide all or none of the above advantages and improvements and still be within the scope of the present disclosure.

[0064] The specific dimensions, specific materials, and / or specific shapes disclosed herein are exemplary in nature and do not limit the scope of the present disclosure. The disclosure herein of a specific value and a specific range of values ​​for a given parameter does not exclude other values ​​and ranges of values ​​that may be useful in one or more examples disclosed herein. Furthermore, it is contemplated that any two specific values ​​for a particular parameter described herein may define the endpoints of a range of values ​​that may be suitable for the given parameter (i.e., the disclosure of a first and a second value for a given parameter can be interpreted as disclosing that any value between the first and second values ​​can be used for the particular parameter). For example, if parameter X is exemplified herein as having a value A and also as having a value Z, it is contemplated that parameter X may have a range of values ​​from about A to about Z. Similarly, the disclosure of two or more ranges of values ​​for a parameter (whether such ranges are nested, overlapping, or separate) is contemplated to encompass all possible combinations of ranges of values ​​that may be claimed using the endpoints of the disclosed ranges. For example, if a parameter X is exemplified herein as having a value in the range of 1 to 10, or 2 to 9, or 3 to 8, it is also contemplated that the parameter X may have other ranges of values, including 1 to 9, 1 to 8, 1 to 3, 1 to 2, 2 to 10, 2 to 8, 2 to 3, 3 to 10, and 3 to 9.

[0065] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. For example, when permissive phrases such as "may include" or "may include" are used herein, at least one embodiment includes the feature. As used herein, the singular forms "a," "an," and "the" may be intended to include the plural forms as well, unless the context clearly dictates otherwise. The terms "comprise," "include," and "have" are inclusive and thus specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Method steps, processes, and operations described herein should not be construed as necessarily requiring their performance in the particular order described or illustrated, unless specifically identified as an order of performance. It should also be understood that additional or alternative steps may be employed.

[0066] When an element or layer is described as "on," "engaged with," "connected to," or "bonded to" another element or layer, it may be directly on, engaged with, connected to, or bonded to that other element or layer, or to intervening elements or layers that may be present. In contrast, when an element is described as "directly on," "directly engaged with," "directly connected to," or "directly bonded to" another element or layer, there may be no intervening elements or layers. Other words used to describe relationships between elements should be interpreted in a similar manner (e.g., "between" and "directly between," "adjacent" and "directly adjacent," etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0067] The term "about," when applied to a value, indicates that the calculation or measurement allows for slight imprecision in the value (approximately or reasonably close to the value, depending on the approach to the accuracy of the value; approximately). If, for some reason, the imprecision provided by "about" is not understood in this ordinary sense in the art, "about," as used herein, refers to at least the variation that can result from ordinary methods of measuring or using such parameters. For example, the terms "generally," "about," and "substantially" can be used herein to mean within manufacturing tolerances. Alternatively, for example, the term "about," as used herein, when used to vary the amounts of components or reactants of the present invention, refers to variations in numerical values ​​that can occur, for example, in typical measuring and handling procedures used in producing concentrates or solutions in the real world, through inadvertent errors in these procedures, or through differences in the manufacture, source, or purity of components used to make the composition or carry out the method. The term "about" also encompasses amounts that differ due to different equilibrium conditions of a composition resulting from a particular initial mixture. Numerical quantities and equivalents are included regardless of whether they are modified by the term "about."

[0068] Terms such as "first," "second," and "third" may be used herein to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or section from another region, layer, or section. When used herein, terms such as "first," "second," and other numerical terms do not imply an order or sequence unless clearly indicated by context. Thus, a first element, component, region, layer, or section discussed below could be referred to as a second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0069] Spatially relative terms such as "inside," "outside," "below," "down," "lower," "upper," "above," and the like may be used herein to facilitate the description of the relationship of one element or feature to another, as shown in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation shown in the figures. For example, if the device in the figures is turned over, elements described as "below" or "below" other elements or features would then become "above" the other elements or features. Thus, the example term "below" can encompass both an orientation of above and below. The device may be oriented differently (rotated 90 degrees or in another orientation), and the spatially relative descriptors used herein may be interpreted accordingly.

[0070] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements, intended or described uses, or features of a particular embodiment are in most cases not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in selected embodiments even if not specifically shown or described. The same can also be modified in many ways. Such modifications should not be considered a departure from the disclosure, and all such variations are intended to be included within the scope of the disclosure.

Claims

1. A method comprising adding at least one of halloysite, hollow nanotubular inorganic structures, and tubular inorganic nanomaterials to a composite in an amount sufficient to reduce migration of material from the composite.

2. 10. The method of claim 1, comprising adding the halloysite to the composite in an amount sufficient to reduce material migration from the composite.

3. 10. The method of claim 1, comprising adding the hollow nanotubular inorganic structures to the composite in an amount sufficient to reduce material migration from the composite.

4. The method of claim 1 , comprising adding the tubular inorganic nanomaterial to the composite in an amount sufficient to reduce material migration from the composite.

5. At least one of the halloysite, the hollow nanotubular inorganic structure, and the tubular inorganic nanomaterial comprises a hollow nanotubular halloysite structure; and 10. The method of claim 1, wherein the method comprises adding the hollow nanotubular halloysite structures to the composite in an amount sufficient to reduce material migration from the composite.

6. At least one of the halloysite, hollow nanotubular inorganic structure, and tubular inorganic nanomaterial comprises a tubular halloysite nanomaterial; and 10. The method of claim 1, wherein the method comprises adding the tubular halloysite nanomaterial to the composite in an amount sufficient to reduce material migration from the composite.

7. 7. The method of any one of claims 1 to 6, wherein the halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials are present in an amount sufficient to reduce silicone oil bleeding from the composite, thereby substantially or completely preventing silicone from migrating outside the confines of the composite, rendering the composite usable and easily deflectable under the application of low levels of force.

8. The method according to any one of claims 1 to 6, wherein the composite is a polydimethylsiloxane (PDMS) based polymer-inorganic composite.

9. The method of any one of claims 1 to 6, wherein the composite is a polymer-inorganic composite that is substantially free of siloxane polymers.

10. The composite material comprises: thermally conductive filler, Conductive filler, Electromagnetic wave absorbing filler, dielectric absorbing filler, and A filler having two or more properties selected from the group consisting of thermal conductivity, electrical conductivity, dielectric absorption, and electromagnetic wave absorption. The method of any one of claims 1 to 6, further comprising adding one or more of:

11. 7. The method of any one of claims 1 to 6, wherein the halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials are present in an amount sufficient to absorb and / or bind non-crosslinked polymers of the composite that may migrate out of the composite.

12. 7. The method of any one of claims 1 to 6, wherein the halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials are present in an amount sufficient to absorb lightly cross-linked and / or low molecular weight cross-linked polymers and other fluid materials and additives that may migrate from the composite.

13. 7. The method of any one of claims 1 to 6, wherein the composite comprises up to about 10 weight percent of halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials.

14. The method of any one of claims 1 to 6, wherein the composite is a thermal interface material, an EMI absorber, a thermally conductive absorber, a conductive elastomer, a conductive composite, or a combination of two or more thereof.

15. The method of any one of claims 1 to 6, wherein the composite is a thermal management and / or electromagnetic interference (EMI) mitigation material that can be used to manage the thermal and / or electromagnetic properties of a device or system.

16. A method according to any one of claims 1 to 6, comprising using the composite to manage the thermal and / or electromagnetic properties of a device or system.

17. 7. A method according to any one of claims 1 to 6, comprising dispensing the composite onto a surface of a device to manage thermal and / or electromagnetic properties of the device and / or of a system including the device.

18. removing the release liner from the composite; and disposing said composite material on a surface of said device to manage the thermal and / or electromagnetic properties of said device and / or of a system including said device; The method according to any one of claims 1 to 6, comprising:

19. A composite comprising halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials in an amount sufficient to reduce material migration from the composite.

20. At least one of the halloysite, the hollow nanotubular inorganic structure, and the tubular inorganic nanomaterial comprises halloysite; and 20. The composite of claim 19, wherein the composite comprises the halloysite in an amount sufficient to reduce material migration from the composite.

21. At least one of the halloysite, the hollow nanotubular inorganic structure, and the tubular inorganic nanomaterial comprises a hollow nanotubular inorganic structure; and 20. The composite of claim 19, wherein the composite comprises the hollow nanotubular inorganic structures in an amount sufficient to reduce material migration from the composite.

22. At least one of the halloysite, the hollow nanotubular inorganic structure, and the tubular inorganic nanomaterial comprises a tubular inorganic nanomaterial; and 20. The composite of claim 19, wherein the composite comprises the tubular inorganic nanomaterial in an amount sufficient to reduce material migration from the composite.

23. At least one of the halloysite, the hollow nanotubular inorganic structure, and the tubular inorganic nanomaterial comprises a hollow nanotubular halloysite structure; and 20. The composite of claim 19, wherein said composite comprises said hollow nanotubular halloysite structures in an amount sufficient to reduce material migration from said composite.

24. At least one of the halloysite, hollow nanotubular inorganic structure, and tubular inorganic nanomaterial comprises a tubular halloysite nanomaterial; and 20. The composite of claim 19, wherein said composite comprises said tubular halloysite nanomaterial in an amount sufficient to reduce material migration from said composite.

25. 25. The composite of any one of claims 19 to 24, wherein the halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials are present in an amount sufficient to reduce silicone oil bleeding from the composite, thereby substantially or completely preventing silicone from migrating outside the confines of the composite, rendering the composite usable and easily deflectable under the application of low levels of force.

26. The composite of any one of claims 19 to 24, wherein the composite is a polydimethylsiloxane (PDMS) based polymer-inorganic composite.

27. The composite of any one of claims 19 to 24, wherein the composite is a polymer-inorganic composite that is substantially free of siloxane polymers.

28. thermally conductive filler, Conductive filler, Electromagnetic wave absorbing filler, dielectric absorbing filler, and A filler having two or more properties selected from the group consisting of thermal conductivity, electrical conductivity, dielectric absorption, and electromagnetic wave absorption.

25. The composite of any one of claims 19 to 24, further comprising one or more of:

29. 25. The composite of any one of claims 19 to 24, wherein the halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials are present in an amount sufficient to absorb and / or bind non-crosslinked polymer of the composite that may migrate out of the composite.

30. 25. The composite of any one of claims 19 to 24, wherein the halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials are present in an amount sufficient to absorb lightly cross-linked and / or low molecular weight cross-linked polymers and other fluid materials and additives that may migrate from the composite.

31. 25. The composite of any one of claims 19-24, comprising up to about 10 weight percent of halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials.

32. 25. The composite of any one of claims 19 to 24 configured for use in managing thermal and / or electromagnetic properties of a device or system.

33. 25. The composite of any one of claims 19 to 24, which is a thermal management and / or electromagnetic interference (EMI) mitigation material.

34. 25. The composite of any one of claims 19 to 24, which is a thermal interface material, an EMI absorber, a thermally conductive absorber, a conductive elastomer, a conductive composite, or a combination of two or more thereof.

35. A composite according to any one of claims 19 to 24 for use in managing the thermal and / or electromagnetic properties of a device or system.

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