Thermal and electrical conductivity control in hybrid composites with graphene and boron nitride fillers

Lewis, Jacob; Barani, Zahra; Magana, Andres Sanchez; Kargar, Fariborz; Balandin, Alexander A.

doi:10.1088/2053-1591/ab2215

Cited by 115 publications

(80 citation statements)

References 84 publications

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“…In some cases, the application of smaller size Cu-NPs can also be beneficial to prevent agglomeration or take advantage of the size dissimilarity to achieve the "synergistic effects". [31][32][33][34][35][36][37][38][39][40][41] Cu-NPs with 100 nm size distribution are mixed with the resin in pre-calculated proportions inside a glove box in the argon gas atmosphere ( Figure 1a). The level of oxygen inside the glove box is carefully monitored and kept below ≈0.2 ppm to prevent oxidation of Cu-NPs.…”

Section: Resultsmentioning

confidence: 99%

“…However, a certain range in the size distribution of FLG fillers turned out to be even beneficial. The size distribution of the fillers can result in the “synergistic” effect, characteristic for the fillers of different dimensions . The “synergistic” effects constitutes a stronger enhancement of the thermal conductivity of the composites with the size‐dissimilar binary fillers than with the individual fillers of the same total concentration .…”

Section: Introductionmentioning

confidence: 99%

“…[31][32][33][34][35][36][37][38][39][40][41] The "synergistic" effects constitutes a stronger enhancement of the thermal conductivity of the composites with the size-dissimilar binary fillers than with the individual fillers of the same total concentration. [31][32][33][34][35][36][37][38][39][40][41] Recent technological advancements made it possible to produce FLG fillers of different sizes and thicknesses using LPE [42,43] or graphene oxide reduction methods. [44][45][46][47][48] These developments open up a possibility of industrial production of composites with the high loading of graphene.…”

Section: Introductionmentioning

confidence: 99%

“…The use of fillers of different sizes and aspect ratios is considered to be promising for achieving strong enhancement of thermal properties via "synergistic effect". [31][32][33][34][35][36][37][38][39][40][41] Here, we report the results of the investigation of the thermal conductivity of the epoxy composites with hybrid fillers comprised of FLG with the large lateral size (few µm) and copper nanoparticles (Cu-NP) with the small lateral size (few nm). In the high-loading composites with FLG and Cu-NP fractions of f g = 40 wt% and f Cu = 35 wt%, we achieved 13.5 ± 1.6 Wm −1 K −1 thermal conductivity, which translates into ≈6750% enhancement of the polymer's thermal conductivity.…”

Section: Introductionmentioning

confidence: 99%

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Thermal Properties of the Binary‐Filler Hybrid Composites with Graphene and Copper Nanoparticles

Barani

Mohammadzadeh

Geremew

et al. 2019

Adv Funct Materials

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225

160

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The thermal properties of epoxy‐based binary composites comprised of graphene and copper nanoparticles are reported. It is found that the “synergistic” filler effect, revealed as a strong enhancement of the thermal conductivity of composites with the size‐dissimilar fillers, has a well‐defined filler loading threshold. The thermal conductivity of composites with a moderate graphene concentration of fg = 15 wt% exhibits an abrupt increase as the loading of copper nanoparticles approaches fCu ≈ 40 wt%, followed by saturation. The effect is attributed to intercalation of spherical copper nanoparticles between the large graphene flakes, resulting in formation of the highly thermally conductive percolation network. In contrast, in composites with a high graphene concentration, fg = 40 wt%, the thermal conductivity increases linearly with addition of copper nanoparticles. A thermal conductivity of 13.5 ± 1.6 Wm−1K−1 is achieved in composites with binary fillers of fg = 40 wt% and fCu = 35 wt%. It has also been demonstrated that the thermal percolation can occur prior to electrical percolation even in composites with electrically conductive fillers. The obtained results shed light on the interaction between graphene fillers and copper nanoparticles in the composites and demonstrate potential of such hybrid epoxy composites for practical applications in thermal interface materials and adhesives.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Thermal Properties of the Binary‐Filler Hybrid Composites with Graphene and Copper Nanoparticles

Barani

Mohammadzadeh

Geremew

et al. 2019

Adv Funct Materials

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225

160

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“…Mater. 2020, 6,1901303 Graphene is added to the base material with acetone followed by the slow speed sheer mixing. The optimized mixing process separates the graphene and mineral oil mix from the acetone.…”

Section: Thermal Conductivity Measurements and Data Analysismentioning

confidence: 99%

Noncuring Graphene Thermal Interface Materials for Advanced Electronics

Naghibi

Kargar

Wright

et al. 2020

Adv Elect Materials

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development of next generation of compact and flexible electronics. [1] The increase in computer usage and ever-growing dependence on cloud systems require better methods for dissipating heat away from electronic components. The important ingredients of thermal management are the thermal interface materials (TIMs). Various TIMs interface two uneven solid surfaces where air would be a poor conductor of heat, and aid in heat transfer from one medium into another. Two important classes of TIMs include curing and noncuring composites. Both of them consist of a base, i.e., matrix materials, and thermally conducting fillers. Commonly, the studies of new fillers for the use in TIMs start with the curing epoxybased composites owing to the relative ease of preparation and possibility of comparison with a wide range of other epoxy composites. Recent work on TIMs with carbon fillers have focused on curing composites, which dry to solid. [2][3][4][5][6][7] Curing TIMs are required for many applications, e.g. attachment of microwave devices, but do not cover all thermal management needs. Thermal management of computers requires specifically noncuring TIMs, which are commonly referred to as thermal pastes or thermal greases. They are soft pliable materials, which unlike cured epoxy-based composites, or phase change materials, remain soft once applied. This aids in avoiding crack formations in the bond line due to repeated thermal cycling of two connected materials with different temperature expansion coefficients. Noncuring TIMs also allow for easy reapplication, known as a TIM's reworkability property. Noncuring TIMs are typically cost efficient-an essential requirement for commercial applications. Various applications in electronics, noncuring grease-like (soft) TIMs are preferred. Examples of the applications include but are not limited to cooling of servers in large data centers [8] and personal devices which are the primary targets for these applications. Current commercially available TIMs perform in thermal conductivity range of 0.5-5 Wm −1 K −1 with combination of several fillers at high loading fractions. [9] State-of-the-art and next-generation electronic devices require thermal pastes with bulk thermal conductivity in the range of 20-25 Wm −1 K −1 . [10,11] This study focuses specifically on noncuring TIMs with graphene and few-layer graphene (FLG) fillers.Curing and noncuring TIMs consists of two main components-a polymer or oil material as its base and fillers, Development of next-generation thermal interface materials (TIMs) with high thermal conductivity is important for thermal management and packaging of electronic devices. The synthesis and thermal conductivity measurements of noncuring thermal paste, i.e., grease, based on mineral oil with a mixture of graphene and few-layer graphene flakes as the fillers, is reported. The graphene thermal paste exhibits a distinctive thermal percolation threshold with the thermal conductivity revealing a sublinear dependence on the filler loading. This behavior contrasts wi...

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Multifunctional Graphene Composites for Electromagnetic Shielding and Thermal Management at Elevated Temperatures

Barani

Kargar

Mohammadzadeh

et al. 2020

Adv Elect Materials

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EM radiation. For this reason, the electronic components have to be protected from the intra-and inter-system EM radiations in order to avoid fast degradation and failure. [4-14] It has also been suggested that prolonged exposure to even nonionizing EM waves in the MHz and GHz frequency range may have detrimental effects on humans and other living beings making the EMI shielding important from safety perspectives. [15-19] The dense packing of the electronic components in the state-of-the-art 2D, 2.5D, and 3D integrated systems and generation of high heat fluxes create an environment with high temperatures, which adversely affect the efficiency and stability of the EMI shielding materials. [20,21] The absorption of EM waves results in the temperature rise of the material making the situation even worse. The data on the efficiency of the conventional and recent EM shield materials in most cases are limited to room temperature (RT) operation. [20-23] The latter is despite the fact that many new non-metallic materials, introduced for EMI shielding, suffer from thermal instability, oxidation, or significant reduction in the shielding efficiency at high temperatures. These concerns require development of novel multifunctional materials, which can serve concurrently as an excellent EM shields with the high thermal stability and conductivity at elevated temperatures. The ability of such materials to act as the thermal interface materials (TIMs) which can dissipate heat efficiently becomes a necessity rather than an extra bonus feature. [2,3,20,21,24] TIMs are applied between two solid surfaces in order to fill the microscopic voids at the interface, and enhance the thermal transport from a heat source to a heat sink. [25-27] The base materials for TIMs are amorphous polymers, which have low thermal conductivity, typically in the range from 0.2 to 0.5 Wm −1 K −1. [28] For this reason, the polymers used as base materials for TIMs are filled with highly thermally conductive fillers to enhance their overall thermal conductivity. The lowweight, mechanical stability, resistance to oxidation, flexibility, and ease of manufacturing are other important criteria for TIMs. EMI shielding materials block the incident EM waves by reflection and absorption mechanisms. Both mechanisms

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Thermal and electrical conductivity control in hybrid composites with graphene and boron nitride fillers

Cited by 115 publications

References 84 publications

Thermal Properties of the Binary‐Filler Hybrid Composites with Graphene and Copper Nanoparticles

Thermal Properties of the Binary‐Filler Hybrid Composites with Graphene and Copper Nanoparticles

Noncuring Graphene Thermal Interface Materials for Advanced Electronics

Multifunctional Graphene Composites for Electromagnetic Shielding and Thermal Management at Elevated Temperatures

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