Thermal Interface Materials Research Articles

Machine learning–enabled direct ink writing of conductive polymer composites for enhanced performance in thermal management and current protection

This study introduces a novel approach that leverages the synergy of machine learning (ML) and Direct Ink Writing (DIW) to optimize the manufacturing feasibility of conductive polymer composites (CPCs) films. The main research focus centers on precisely fine-tuning the printing parameters to strike the perfect balance between the high loading of dendritic copper fillers and their influences on processing and composite performance properties. This pioneering combination significantly enhances the precision of the final product without resorting to time-consuming procedures. ML algorithms contributed to identifying optimal printing variables such as speed, flow pressure, and filler concentration, which helped in identifying the optimal filler content and its performance capabilities. The resulting films exhibited thermo-resistive behavior with a noticeable resistivity increase by 6-7 orders of magnitude at elevated temperatures, specifically around 100 °C. Furthermore, the study highlights remarkable strain-sensing capabilities, simultaneously showcasing a substantial increase in composite modulus. These discoveries bear substantial significance for the development of exceptionally functional thermal interface materials suitable for use in sensors, current collectors, and energy storage devices. The method presented here offers a promising pathway for advancing the fabrication and performance optimization of conductive polymer composites, opening up diverse applications in emerging technologies.

Dry media reaction-based anti-hydration coating on magnesium oxide microspheres for thermal interfacial applications

Magnesium oxide (MgO) is gaining attention as a next-generation thermal management material due to its better thermal conductivity compared to other oxides and excellent insulating properties. However, its susceptibility to hydration when exposed to atmosphere, which alters its material properties, necessitates the application of anti-hydration coatings for its use in thermal management. This study explores the use of Chemical Vapor Deposition (CVD) and Plasma-Enhanced Chemical Vapor Deposition (PECVD) as alternatives to the traditional sol–gel method to form anti-hydration coatings on MgO microspheres. The surface modification process was completed within 20 min for both processes, and the water contact angles of the spheres increased from ∼33° to ∼98° with CVD and ∼125° with PECVD. Compared to CVD, PECVD was found to be more effective in applying anti-hydration coatings, thanks to the plasma activation of the MgO surface and reactants, thereby better maintaining the physical and chemical properties under conditions of 85 °C and 85 % relative humidity. Furthermore, when used as a filler in thermal interface material composites, MgO modified with PECVD exhibited adhesion strength and thermal conductivity about 1.5 times higher than bare MgO, due to the increased affinity for the hydrophobic binder.

Automobile exhaust flexible thermoelectric harvester enabled by liquid metal-based heatsink

The softening thermoelectric generator based on a deformable heatsink is expected to facilitate achieving remarkable temperature differences and thermal harvesting capabilities while alleviating exhaust back pressure and engine operating perturbations. However, the available soft polymer materials with poor thermal characteristics face challenges in realizing efficient heat transfer. Herein, we reported a highly integrated automobile exhaust flexible thermoelectric generator (IAE-FTEG) enabled by a liquid metal (LM)-based stretchable heatsink for cylindrical thermal sources to achieve efficiently harnessing waste heat energy and continuously powering multiple vehicle-mounted sensors. IAE-FTEG exhibits excellent flexibility (the bending radius at the apex of 0.57 cm) and outstanding heat transfer capability by introducing the porous sandwich-based soft electrode films and LM-based thermal interface material, achieving an output power enhancement of 25.7 %. The flexible heatsink is prepared by embedding LM droplets and copper particles into the elastic matrix forming solid–liquid multiphase composites, which obtain considerable thermal conductivity (2.40 W/mK@200 % stretching deformation) and excellent geometric conformity. We built the bench and the real vehicle test platform of the IAE-FTEG waste heat recovery system. The simulation test results demonstrate that the maximum power density achieved by the IAE-FTEG waste heat recovery system is 244 kW/m3. The real vehicle tests show that the IAE-FTEG waste heat recovery system has a relatively stable output performance with an average power density of 117 kW/m3 under urban conditions and can realize a stable power supply for back-end loads. Our IAE-FTEG can offer new opportunities in enabling efficient curved-surface waste heat recovery, flexible wearable electronics, and personalized thermal management.

Effect of graphene arrangement on the thermal conductivity of graphene/polymer nanocomposites

ABSTRACT Due to its high thermal conductivity (up to 5300 W/mK), graphene is considered an ideal filler for composites with a polymer matrix to form a thermal interface material with excellent thermal performance. The thermal conductivity of graphene/polymer nanocomposites can be effectively improved by increasing the aspect ratio of graphene, simultaneously increasing the lateral size and thickness of graphene at a constant aspect ratio or changing the ordered orientation of graphene nanosheets (GNSs) filled in the polymer matrix. Experimental results have shown that the ultrahigh thermal conductivity of the composites can be achieved in the in-plane direction due to the minimum interface thermal resistance along this direction. To detect the arrangement structure of GNSs on the thermal conductivity of the composites, this paper obtained the expressions of the effective thermal conductivity for anisotropic GNSs/polymer composites based on the multiple-scattering theory, where the effect of the number of GNSs layers on the interface thermal resistance and thermal conductivity of GNSs is considered. The numerical results show that the composites parallel to the aligned direction of GNSs have greater thermal conductivity than those perpendicular to it. The ordered orientation of GNSs can effectively improve the thermal conductivity for GNSs/polymer nanocomposites.

Exploring the Impact of Visual Heat Conduction Paths on Thermal Conductivity of Polymer Composites and the Practical Applications.

The theory of heat conduction paths has been widely recognized and widely studied in the research about the thermal conductivity of thermal conductive polymer composites at present. Encapsulating polymer pellets with thermally conductive fillers and processing them into thermally conductive polymer composites is a simple and effective method for constructing heat conduction paths. It is meaningful to investigate the related heat conduction mechanism of this method. Otherwise, this approach can significantly preserve the performance of the polymer substrate, making it highly valuable for practical material applications. In this work, polyethylene-octene elastomer (POE) pellets were encapsulated with thermal conductive fillers by physical absorption. Subsequently, the composite films containing heat conduction paths were fabricated using the encapsulated POE pellets through a heating press. Alumina (Al2O3), boron nitride (BN), and alumina/boron nitride hybrid (Al2O3/BN) fillers were used to prepare Al2O3@POE, BN@POE, and BN/Al2O3@POE composite films to investigate the influence of filler shapes on heat conduction path construction. The influence of the constitute and density of heat conduction paths on the thermal conductivity of composite films was analyzed by infrared thermal imaging, finite element analysis, and thermal resistance theory in detail. Owing to the reserved good adhesion and flexibility of the POE substrate, the composite films could be directly used as thermal interface materials for chip cooling, which presented a good heat dissipation effect. Furthermore, a series of integrated composite materials were prepared by the combination of encapsulated pellets with various functional films (copper foil, aluminum foil, and graphite sheet) through a one-pot heating press, exhibiting a good electromagnetic shielding effect. The performance of the composites and the corresponding preparation method demonstrate the strong significance of this research for practical applications.

Diamond-Reinforced Al(H2PO4)3@Epoxy Hybrid Thermal Adhesive With Ultra-High Thermal Conductivity and Bonding Strength.

The miniaturization, integration, and increased power of electronic devices have exacerbated serious heat dissipation issues. Thermally conductive adhesives, which effectively transfer heat and firmly bond components, are critical for addressing these challenges. This paper innovatively proposed a composite comprising inorganic phosphate/alumina as a matrix and diamond as filler. The composite achieved an isotropic thermal conductivity (TC) of up to 18.96Wm-1K-1, significantly surpassing existing reports while maintaining electrical insulation. First-principles calculations and experimental tests confirmed that the high TC of phosphate and excellent interface contact ensured efficient heat transfer. To optimize bonding performance, a modified-diamond/Al(H2PO4)3@epoxy hybrid composite is subsequently developed using an organic modification method. The unique hybrid structure, combining inorganic thermal pathways and an organic adhesive network, enabled the hybrid composite to simultaneously possess a high TC (3.23Wm-1K-1) and strong adhesion (14.35MPa). Compared to previous reports, the comprehensive performance of this hybrid thermally conductive adhesive is exceptionally remarkable. The superior heat dissipation capability of the hybrid thermal adhesive is demonstrated in chip cooling scenarios. This organic/inorganic hybrid approach offered a new direction for obtaining advanced thermal interface materials, demonstrating significant application potential in chip soldering, packaging, and heat dissipation.

Predicting bond line thickness of polymeric thermal interface materials based on the rheological properties

Bond line thickness (BLT) is an essential parameter of thermal conductive composite gels as the thermal interface material (TIM). Extensive research has been performed on designing next-generation TIMs with high thermal conductivity; however, it remains elusive how to link laboratory measurements and the theoretically predicted BLT. Here, we propose a new model to estimate BLT based on a rheological property, in which the TIM is assumed to be a simple power law fluid. To avoid the unrealistic situation of the BLT tending to zero, we introduce a decaying exponential function to describe the influence from fillers during the lid attach process and rebuild the force balance equation. Compared with previously reported models, the theoretical prediction BLT based on the proposed model is in good agreement with the experimental data. Our model has a guiding significance in predicting the BLT, which may help to optimize the thermal performance of TIMs.

Thermally Conductive Hexagonal Boron Nitride/Polymer Composites for Efficient Heat Transport

AbstractCommercial thermally conductive dielectric materials used in electronic packaging typically exhibit thermal conductivities (κ) ranging from 0.8 to 4.2 W m−1 K−1. Hexagonal boron nitride (h‐BN) flakes are promising thermally conductive materials for the thermal management of next‐generation electronics. These electrically insulating yet thermally conducting h‐BN flakes can be incorporated as thermal fillers to impart high κ to polymer‐based composites. A cellulose‐based composite embedded with few‐layer h‐BN (FLh‐BN) flakes, achieving a κ ≈ 21.7 W m−1 K−1, prepared using a cost‐effective and scalable procedure is demonstrated. This value is >5 times higher than the κ observed in composites embedded with bulk h‐BN (Bh‐BN, κ ≈ 4.5 W m−1 K−1), indicating the benefits of the superior κ of FLh‐BN on the κ of h‐BN polymer composites. When applied as a paste for thermal interface material (TIM), the FLh‐BN composite can reduce the maximum temperature (Tmax) by 24.5 °C of a heating pad at a power density (h) of 2.48 W cm−2 compared to Bh‐BN composites at the same h‐BN loading. The results provide an effective approach to improve the κ of cellulose‐based thermal pastes for TIMs and demonstrate their viability for heat dissipation in integrated circuits (ICs) and high‐power electronic devices.

Numerical Investigation on Thermal Conductivity of Graphene Foam Composite for Thermal Management Applications.

Graphene foam prepared by the chemical vapor deposition method is a promising thermal interfacial material. However, the thermal properties of graphene foam highly depend on the experimental fabrication conditions during the chemical vapor deposition process. Aiming to reveal how to prepare the appropriate graphene foam for the various thermal management scenarios, the influence of experimental conditions on thermal properties of graphene foam was investigated. Furthermore, the contribution of thermal conductivity and thermal radiation to the effective thermal coefficient of graphene foam was carried out for comparison. The research results showed that the porosity and the cross-section shape of the struts of the growth template were two critical factors affecting the thermal transport of graphene foam, especially with the increase of temperature. In addition, the deposition time of graphene determined the wall thickness and affected the thermal conductivity directly. The thermal radiation contributed more than thermal conductivity when the temperature climbed continuously. Comparatively, the effective thermal coefficient of graphene foam composite with high porosity and circular-shape struts was much superior to that of others at high temperature. The research findings provide important guidance for graphene foam fabrication and its applications in the field of thermal management.

Characterization of Composite Materials Using Carbon Nano Tube Carboxy Group Introduction and Aluminum Oxide Synthesis

The high integration and high density of semiconductor packages are generating increased heat in electronic devices, leading to issues such as reduced lifespan and malfunctions in electronic devices. In response, research on thermal interface materials is being conducted to address heat generated from heat sources, and various studies, particularly those applying carbon nano tube, are notable in this regard. However, in the case of carbon nano tube, there are challenges in industrial application due to the occurrence of cohesive forces through van der Waals interactions. Therefore, in this study, the characteristics were analyzed through the formation of carbon nano tube carboxyl groups (–COOH) and the synthesis of aluminum oxide via chloride (–COCl) formation. After the chloride process, a functional group –COCl was confirmed at 430 cm−1. It was confirmed that the electrical properties were improved as a result of the CNT, CNT carboxyl, and chloride process. It is believed that the electrical properties improved as impurities were removed during the acid treatment process. In addition, it is believed that the electrical properties were improved due to the increase in intermolecular forces between CNTs. Through this, it is determined that the application of carbon nano tube and aluminum oxide composite materials can be highly beneficial for thermal conductivity heat dissipation filler applications.

Chemical heterogeneity size effects at nanoscale on interface thermal resistance of solid–liquid polymer interface via molecular dynamics simulations

The shrinking size of integrated chips poses thermal management challenges. Understanding the size effect of chemical heterogeneity on solid–liquid interfacial thermal transfer is essential for heterogeneous chip design, yet the underlying mechanisms remain lacking. The present work used the liquid n-alkanes as the thermal interface material between solid platinum substrates. To characterize chemical heterogeneity, periodic solid surface patterns composed of patches with alternating solid–liquid affinities were constructed. By using non-equilibrium molecular dynamics simulations, we investigated the size effect of chemically heterogeneous patterns on interfacial thermal resistance (ITR) at the nanoscale. At larger heterogeneity sizes, i.e., larger patch sizes, most alkane molecules directly in contact weak interaction patches cannot interact with strong interaction patches due to long atomic distances. In the case of alkanes in contact a cold substrate, alkanes in contact weak interaction patches transferred thermal energy to the substrate at a lower rate than those in contact strong interaction patches. The different rates resulted in the higher temperature of alkanes in contact weak interaction patches than those in contact strong interaction patches and, therefore, a larger disparity between temperature jump at the strong interaction areas and that at the weak interaction areas. The non-uniformity of temperature jump distribution increased ITR when compared to the heterogeneous surface system characterized by a smaller patch size with a more uniform temperature distribution in the plane perpendicular to the heat flux direction. In addition, the classical parallel thermal resistance model predicted ITR accurately for the heterogeneous surface systems with small size patches but overestimated overall thermal resistance.

Enhancement of Thermal Management Performance of Copper Foil Using Additive-Free Graphene Coating.

Advanced thermal interface materials with high thermal conductivity are crucial for addressing the heat dissipation issue in high-power, highly integrated electronic devices. One great potential way in this field is to take advantage of cooling copper foil (Cu) materials based on graphene (G). However, the current manufacturing of these cooling copper foil materials is accompanied by high cost, process complexity, and environmental problems, which limit their development and application. In this work, a simple, low-cost, environmentally friendly graphene-copper foil composite film (rGO/G-Cu) with high thermal conductivity was successfully prepared using graphene oxide directly as a dispersant and binder of graphene coating. The microstructure characterization, thermal conductivity and thermal management performance tests were carried out on the composite films. The results demonstrate that compared to pure copper foil (342.47 W·m-1·K-1) and 10% PVA/G-Cu (367.98 W·m-1·K-1) with polyvinyl alcohol as a binder, 10% rGO/G-Cu exhibits better thermal conductivity (414.56 W·m-1·K-1). The introduction of two-dimensional graphene oxide effectively enhances the adhesion between the coating and the copper foil while greatly improving its thermal conductivity. Furthermore, experimental results indicate that rGO/G-Cu exhibits excellent heat transfer performance and flexibility. This work is highly relevant to the development of economical and environmentally friendly materials with high thermal conductivity to meet the increasing demand for heat dissipation.

Scalable Compliant Graphene Fiber-Based Thermal Interface Material with Metal-Level Thermal Conductivity via Dual-Field Synergistic Alignment Engineering.

High-performance thermal interface materials (TIMs) are highly desired for high-power electronic devices to accelerate heat dissipation. However, the inherent trade-off conflict between achieving high thermal conductivity and excellent compliance of filler-enhanced TIMs results in the unsatisfactory interfacial heat transfer efficiency of existing TIM solutions. Here, we report the graphene fiber (GF)-based elastic TIM with metal-level thermal conductivity via mechanical-electric dual-field synergistic alignment engineering. Compared with state-of-the-art carbon fiber (CF), GF features both superb high thermal conductivity of ∼1200 W m-1 K-1 and outstanding flexibility. Under dual-field synergistic alignment regulation, GFs are vertically aligned with excellent orientation (0.88) and high array density (33.5 mg cm-2), forming continuous thermally conductive pathways. Even at a low filler content of ∼17 wt %, GF-based TIM demonstrates extraordinarily high through-plane thermal conductivity of up to 82.4 W m-1 K-1, exceeding most CF-based TIMs and even comparable to commonly used soft indium foil. Benefiting from the low stiffness of GF, GF-based TIM shows a lower compressive modulus down to 0.57 MPa, an excellent resilience rate of 95% after compressive cycles, and diminished contact thermal resistance as low as 7.4 K mm2 W-1. Our results provide a superb paradigm for the directed assembly of thermally conductive and flexible GFs to achieve scalable and high-performance TIMs, overcoming the long-standing bottleneck of mechanical-thermal mismatch in TIM design.

Simultaneous Measurement of Thermal Conductivity and Volumetric Heat Capacity of Thermal Interface Materials Using Thermoreflectance.

Thermal interface materials are crucial to minimize the thermal resistance between a semiconductor device and a heat sink, especially for high-power electronic devices, which are susceptible to self-heating-induced failures. The effectiveness of these interface materials depends on their low thermal contact resistance coupled with high thermal conductivity. Various characterization techniques are used to determine the thermal properties of the thermal interface materials. However, their bulk or free-standing thermal properties are typically assessed rather than their thermal performance when applied as a thin layer in real application. In this study, we introduce a low-frequency range frequency domain thermoreflectance method that can measure the effective thermal conductivity and volumetric heat capacity of thermal interface materials simultaneously in situ, illustrated on silver-filled thermal interface material samples, offering a distinct advantage over traditional techniques such as ASTM D5470. Monte Carlo fitting is used to quantify the thermal conductivities and heat capacities and their uncertainties, which are compared to a more efficient least-squares method.

Flexible, thermally conductive, electrically insulated, and high‐temperature resistant PDMS@BN composite films with high orientation degree of BN sheets prepared by facile spin‐coating

AbstractCurrently, flexible thermal interface materials (TIMs) containing hexagonal boron nitride (h‐BN) as thermal conductive fillers become a research hot spot. In this study, PDMS@BN composite films were prepared using spin‐coating technology, providing a facile and efficient method for the preparation of TIMs. The effects of spin‐coating speed and time on the thermal conductivity and the orientation degree of BN within composite films were investigated. Additionally, a theoretical model was established to calculate the thickness and thermal conductivity of PDMS@BN composite films under various spin‐coating conditions. The findings indicate that with an increase of spin‐coating speed and extension of spin‐coating time, the thickness of the composite films gradually decreases, while the in‐plane and through‐plane thermal conductivity gradually increases. When compared to a low spin‐coating speed of 500 rpm, the thermal conductivity of the films produced by a higher speed of 2500 rpm, exhibited an increase of 274%. The film achieves outstanding thermal conductivity (5.79 W m−1 K−1), extremely thin thickness (60 μm), high volume resistivity (1.22 × 1013 Ω cm) and excellent flexibility by incorporating 60 wt % h‐BN flakes. Overall, this study presents an efficiently and eco‐friendly approach for high‐performance TIMs.

2D Materials-Based Thermal Interface Materials: Structure, Properties, and Applications.

The challenges associated with heat dissipation in high-power electronic devices used in communication, new energy, and aerospace equipment have spurred an urgent need for high-performance thermal interface materials (TIMs) to establish efficient heat transfer pathways from the heater (chip) to heat sinks. Recently, emerging 2D materials, such as graphene and boron nitride, renowned for their ultrahigh basal-plane thermal conductivity and the capacity to facilitate cross-scale, multi-morphic structural design, have found widespread use as thermal fillers in the production of high-performance TIMs. To deepen the understanding of 2D material-based TIMs, this review focuses primarily on graphene and boron nitride-based TIMs, exploring their structures, properties, and applications. Building on this foundation, the developmental history of these TIMs is emphasized and a detailed analysis of critical challenges and potential solutions is provided. Additionally, the preparation and application of some other novel 2D materials-based TIMs are briefly introduced, aiming to offer constructive guidance for the future development of high-performance TIMs.

Hexagonal boron nitride nanosheets/graphene nanoplatelets/cellulose nanofibers-based multifunctional thermal interface materials enabling electromagnetic interference shielding and electrical insulation

Thermal interface materials (TIMs) that block electromagnetic interference (EMI) and current leakage are essential for high-density, high-power devices and compact form factors of electronic and mobility platforms. However, their coupled thermal-electrical-electromagnetic characteristics involve mismatches in thermal conductivity, electrical insulation, and EMI shielding, limiting the multifunctionality. Herein, a sandwich-like structural design that rationally combines graphene nanoplatelets (GNPs), hexagonal boron nitride nanosheets (BNNSs) and cellulose nanofibers (CNFs) is presented toward multifunctional trilayer TIMs enabling high thermal conductivity, EMI shielding, electrical insulation, mechanical compatibility and flame retardancy. The top and bottom BNNSs serve as electrically insulating yet thermally conductive layers while the GNPs in the central layer mitigate EMI and the CNFs as a binder complete the mechanical properties for the lamella-like trilayers. The resulting TIM exhibits a high in-plane thermal conductivity (25.5 W/m·K), and the LED cooling system using the TIM demonstrates the capability of reducing the operating temperature. Furthermore, it shows a high-volume resistivity (4.12 × 1013 Ω cm) and EMI shielding effectiveness (29.0 dB) at X-band frequencies. Its mechanical robustness is confirmed with tensile strength and elongation of 65.0 MPa and 2.36 %, and the high flame retardancy is validated. The outcomes will inspire tailoring multifunctional TIMs using lamellar structures that optimally combine micro/nanomaterials.

Determination of Contact Resistance of Thermal Interface Materials Used in Thermal Monitoring Systems of Electric Vehicle Charging Inlets.

The rapid growth of the electric vehicle (EV) market is observed. This is challenging from a materials point of view when it comes to the thermal monitoring systems of charging inlets, for which requirements are very restrictive. Because the thermal conductivity of the thermal interface material is usually measured, there is a significant research gap on the contact thermal resistance of novel materials used in the electric vehicle industry. Moreover, researchers mainly focus on electrically conductive materials, while for thermal monitoring systems, the most important requirement is a high dielectric breakdown voltage. In this paper, the thermal contact resistance of materials for EV applications was thoroughly analyzed. This study consisted of experimental measurements with the Laser Flash Analysis (LFA) method, as well as a theoretical analysis of thermal contact resistance. The main focus was on the extraction of contact and material thermal resistance. The obtained results have great potential to be used as input data for further numerical modeling of solutions that meet strict thermal accuracy requirements. Additionally, the chemical composition and internal structure were analyzed using scanning electron microscopy, to better describe the material.

Aluminum/Graphene Thermal Interface Materials with Positive Temperature Dependence.

Graphene is widely used in excellent thermal interface materials (TIMs), thanks to its remarkably high in-plane thermal conductivity (k∥). However, the poor through-plane thermal conductivity (k⊥) limits its further application. Here, we developed a simple in situ growth method to prepare graphene-based thermal interface composites with positively temperature-dependent thermal conductivity, which loaded aluminum (Al) nanoparticles onto graphene nanoplatelets (GNPs). To evaluate the variations in thermal performance, we determined the thermal diffusivity and specific heat capacity of the composites using a laser-flash analyzer and a differential scanning calorimeter, respectively. The Al nanoparticles act as bridges between the nanoplatelets, enhancing the k⊥ of the 1.3-Al/GNPs composite to 11.70 W·m-1·K-1 at 25 °C. Even more remarkably, those nanoparticles led to a unique increase in k⊥ with temperature, reaching 20.93 W·m-1·K-1 at 100 °C. Additionally, we conducted an in-depth investigation of the thermal conductivity mechanism of the Al/GNPs composites. The exceptional heat transport property enabled the composites to exhibit a superior heat dissipation performance in simulated practical applications. This work provides valuable insights into utilizing graphene in composites with Al nanoparticles, which have special thermal conductivity properties, and offers a promising pathway to enhance the k⊥ of graphene-based TIMs.

SPI-Modified h-BN Nanosheets-Based Thermal Interface Materials for Thermal Management Applications.

The rising concern over the usage of electronic devices and the operating environment requires efficient thermal interface materials (TIMs) to take away the excess heat generated from hotspots. TIMs are crucial in dissipating undesired heat by transferring energy from the source to the heat sink. Silicone oil (SO)-based composites are the most used TIMs due to their strong bonding and oxidation resistance. However, thermal grease performance is unreliable due to aging effects, toxic chemicals, and a higher percentage of fillers. In this work, TIMs are prepared using exfoliated hexagonal boron nitride nanosheets (h-BNNS) as a nanofiller, and they were functionalized by ecofriendly natural biopolymer soy protein isolate (SPI). The exfoliated h-BNNS has an average lateral size of ∼266 nm. The functionalized h-BNNS/SPI are used as fillers in the SO matrix, and composites are prepared using solution mixing. Hydrogen bonding is present between the organic chain/oxygen in silicone polymer, and the functionalized h-BNNS are evident from the FTIR measurements. The thermal conductivity of h-BNNS/SPI/SO was measured using the modified transient plane source (MTPS) method. At room temperature, the maximum thermal conductivity is 1.162 Wm-1K-1 (833% enhancement) at 50 wt % of 3:1 ratio of h-BNNS:SPI, and the thermal resistance (TR) of the composite is 5.249 × 106 K/W which is calculated using the Foygel nonlinear model. The heat management application was demonstrated by applying TIM on a 10 W LED bulb. It was found that during heating, the 50 wt % TIM decreases the surface temperature of LED by ∼6 °C compared with the pure SO-based TIM after 10 min of ON condition. During cooling, the modified TIM reduces the surface temperature by ∼8 °C under OFF conditions within 1 min. The results indicate that natural polymers can effectively stabilize and link layered materials, enhancing the efficiency of TIMs for cooling electronics and LEDs.