Thermal Conductivity Enhancement Research Articles

Enhanced Thermal Conductivity of EP Composites by Introducing BN-Al2O3 Hybrid

Enhanced Thermal Conductivity of EP Composites by Introducing BN-Al2O3 Hybrid

Metal ion-crosslinked thermoconductive sugar-functionalized graphene fluoride-based cellulose papers with enhanced mechanical properties and electrical insulation

Thermally conductive papers with electrical insulation and mechanical robustness are essential for efficient thermal management in modern electronics. In this study, we introduced a metal ion-assisted interfacial crosslinking strategy to strengthen sugar-functionalized graphene fluoride (SGF) and cellulose nanofibers (CNF) by hydrogen bonding and metal ion crosslinking that leads to simultaneous enhancements in thermal conductivity and mechanical properties. The facile sugar-assisted ball-milling exfoliation method was developed to achieve the exfoliation of graphite fluoride and hydroxyl group functionalization on the surface of graphene fluoride. Thanks to the good dispersibility of the SGF sheets in water, the flexible SGF/CNF composite papers with hydrogen bonding were prepared via vacuum-assisted filtration. We introduced hydrogen bonding and metal ion crosslinking into SGF/CNF papers to obtain densely packed composite papers. Ca2+ or Al3+ ion-crosslinked SGF/ CNF papers exhibited superior thermal and mechanical properties owing to hydrogen bonding and metal ion crosslinking. SGF/CNF-Ca2+ and SGF/CNF-Al3+ papers at 50 wt% of SGF yield in-plane thermal conductivities of 72.93 and 75.02 W m–1 K–1, and tensile strengths of 121.5 and 135.7 MPa, respectively. A thermal percolation value was observed at 12.6 vol% of SGF filler content. In addition, the SGF/CNF papers exhibited electrical insulation properties. These remarkable characteristics of the metal ion-crosslinked SGF/CNF papers are attributed to the densely packed structures caused by the strong interfacial interactions from hydrogen bonding as well as metal ion-crosslinking that could promote phonon transport. High-performance metal ion-crosslinked SGF/CNF papers with these fascinating advantages offer great potential for the thermal management of flexible electronics.

Thermal Energy Storage in Concrete by Encapsulation of a Nano-Additivated Phase Change Material in Lightweight Aggregates.

This work discusses the applicability of lightweight aggregate-encapsulated n-octadecane with 1.0 wt.% of Cu nanoparticles, for enhanced thermal comfort in buildings by providing thermal energy storage functionality to no-fines concrete. A straightforward two-step procedure (impregnation and occlusion) for the encapsulation of the nano-additivated phase change material in lightweight aggregates is presented. Encapsulation efficiencies of 30-40% are achieved. Phase change behavior is consistent across cycles. Cu nanoparticles provide nucleation points for phase change and increase the rate of progression of phase change fronts due to the enhancement in the effective thermal conductivity of n-octadecane. The effective thermal conductivity of the composites remains like that of regular lightweight aggregates and can still fulfil thermal insulation requirements. The thermal response of no-fines concrete blocks prepared with these new aggregates is also studied. Under artificial sunlight, with a standard 1000 W·m-2 irradiance and AM1.5G filter, concrete samples with the epoxy-coated aggregate-encapsulated n-octadecane-based dispersion of Cu nanoparticles (with a phase change material content below 8% of the total concrete mass) can effectively maintain a significant 5 °C difference between irradiated and non-irradiated sides of the block for ca. 30 min.

0D/2D Co-Doping Network Enhancing Thermal Conductivity of Radiative Cooling Film for Electronic Device Thermal Management.

The radiative cooling has great potential for electronic device cooling without requiring any energy consumption. However, a low thermal conductivity of most radiative cooling materials limits their application. Herein, a multishape codoping strategy was proposed to achieve collaborative enhancement of thermal conductivity and radiative properties. The hBN-coated hollow SiO2 particles were prepared based on electrostatic self-assembly technology, which were then mixed with hBN platelets and doped into a poly(vinylidene fluoride-co-hexafluoropropylene) substrate. Discrete dipole approximation theory was employed to reveal the mechanism and optimize the particle size. The results showed that the multishape codoping method can significantly improve the radiative performance, with 94.9% reflectivity and 91.2% emissivity. In addition, this zero-dimensional and two-dimensional composite doping structure facilitated the formation of a thermal conduction network, which enhanced the thermal conductivity of the film up to 1.32 W m-1 K-1. The high thermal conductivity radiative cooling film can decrease the heater temperature from 58.8 to 31.3 °C, with a further reduction of temperature by 7.2 °C compared to the radiative cooling substrates with low thermal conductivity. The net cooling power of the film can reach 102.5 W m-2 under direct sunlight. This work provides a novel strategy for high-efficiency electronic device cooling.

Physical Adsorption of Polyacrylic Acid on Boron Nitride Nanotube Surface and Enhanced Thermal Conductivity of Poly(vinyl alcohol) Composites.

To fully tap into the potential of boron nitride nanotubes (BNNTs), addressing their inherent insolubility was imperative. In this study, a water-soluble polymer, poly(acrylic acid) (PAA), was employed as a surface-active reagent, using an accessible and scalable approach. The physical properties and structure of PAA-BNNT were meticulously confirmed through valuable characterization techniques, encompassing X-ray diffraction, scanning electron microscopy, Fourier-transform infrared, X-ray photoelectron spectroscopy, and thermogravimetric analysis. PAA-BNNT exhibited remarkable dispersion in water and demonstrated compatibility with the poly(vinyl alcohol) (PVA) matrix. When incorporating 30 wt % of PAA-BNNT (about 24.75 wt % net BNNT) into the PVA matrix, the thermal conductivity surged by over 21.7 times compared to pure PVA due to the uniform dispersion of high-concentration PAA-BNNT in the polymer matrix.

Molecular insights into thermal conductivity enhancement and interfacial heat transfer of molten salt/porous ceramic skeleton composite phase change materials

Molten salt has been considered as one of the most promising candidate materials for thermal energy storage (TES) systems owing to its remarkable energy density and consistent thermal performance. These properties render it particularly advantageous for the applications in concentrated solar power (CSP) and industrial process heat utilization. Nonetheless, their practical applications still face nonnegligible challenges such as the low thermal conductivity and risk of leakage. Packing molten salts into porous skeletons could be an effective way for addressing these issues. In the present work, the heat transfer characteristics of a composite phase change material (CPCM) consisting of binary chloride salt and a porous ceramic skeleton, are investigated at the microscale level using molecular dynamics (MD) simulations. Simulation results indicate that the integration of a porous SiC skeleton can substantially enhance the thermal conductivity of binary molten salt NaCl/KCl. At the temperature of 1000 K, a notable enhancement of 625.74 % in thermal conductivity has been observed. Moreover, the underlying mechanism of heat conduction enhancement has been revealed from the microscopic perspective. The results demonstrate that auxiliary thermal conductivity paths and interfacial heat transfer play primary roles in determining the thermal conductivity of CPCMs. The method of surface charge modification can effectively improve the interfacial heat transfer and the reason can be attributed to the additional thermal conductivity paths and the large number of particles involved in the interfacial heat transfer. The results gained in this work may provide insights into the heat transfer mechanism of composite molten salt/porous skeleton as well as practical guidance for designing CPCM for thermal storage applications.

Tensile strain induced enhancement of lattice thermal conductivity and its origin in two-dimensional SnC

Tensile strain induced enhancement of lattice thermal conductivity and its origin in two-dimensional SnC

Reversible two-way tuning of thermal conductivity in an end-linked star-shaped thermoset

Polymeric thermal switches that can reversibly tune and significantly enhance their thermal conductivities are desirable for diverse applications in electronics, aerospace, automotives, and medicine; however, they are rarely achieved. Here, we report a polymer-based thermal switch consisting of an end-linked star-shaped thermoset with two independent thermal conductivity tuning mechanisms—strain and temperature modulation—that rapidly, reversibly, and cyclically modulate thermal conductivity. The end-linked star-shaped thermoset exhibits a strain-modulated thermal conductivity enhancement up to 11.5 at a fixed temperature of 60 °C (increasing from 0.15 to 2.1 W m−1 K−1). Additionally, it demonstrates a temperature-modulated thermal conductivity tuning ratio up to 2.3 at a fixed stretch of 2.5 (increasing from 0.17 to 0.39 W m−1 K−1). When combined, these two effects collectively enable the end-linked star-shaped thermoset to achieve a thermal conductivity tuning ratio up to 14.2. Moreover, the end-linked star-shaped thermoset demonstrates reversible tuning for over 1000 cycles. The reversible two-way tuning of thermal conductivity is attributed to the synergy of aligned amorphous chains, oriented crystalline domains, and increased crystallinity by elastically deforming the end-linked star-shaped thermoset.

Quantitative analysis of microstructural evolution in cold-sprayed CuCrZr: Understanding heat transfer mechanisms from room temperature to 600°C

Cold-sprayed CuCrZr coating offers interesting multifunctional properties with a combination of high mechanical property, good thermal stability and substantial deposition thickness. Despite these advantages, the incorporation of solid solution elements and the deposit’s unique microstructure often result in suboptimal heat transfer capabilities. This study delved into the thermal conductivity of cold-sprayed CuCrZr coatings over a temperature range from room temperature to 600 °C. Furthermore, it quantitatively analyzed their microstructural evolution post-thermal testing and its correlation with thermal properties, employing techniques such as FESEM, EBSD, TEM, and XRD. Findings indicate the CuCrZr coating exhibits significant thermal sensitivity, with conductivity increasing from 65.83±1.79 W/(m∙K) at 25 °C to 198.42±0.63 W/(m∙K) at 600 °C. The annealing effect during thermal testing significantly enhances the coatings’ room temperature thermal properties, chiefly through the enhancement of interparticle metallurgical bonding, grain enlargement, solid solution precipitation, and a reduction in dislocation density. The thermal conduction across the coating/substrate interface is intricately influenced by the interplay between electrons and phonons, with impediments at the interface becoming markedly pronounced beyond 300 °C. The investigation pinpointed interparticle interfaces as the predominant barriers to heat transfer, contributing to 73.77 % of the total resistance. Meanwhile, the effects of solid solution elements, grain boundaries, and dislocations on thermal conductivity were comparatively minor, contributing 9.36 %, 1.04 %, and 0.44 %, respectively. However, it is also noted that the annealing effect can induce the coalescence of microcracks into pores and promote the precipitation or oxidation of Cr at the interfaces, which, in turn, limits the potential for further enhancements in thermal conductivity.

MHD nonlinear thermally radiative Ag − TiO 2/H 2 O hybrid nanofluid flow over a stretching cylinder with Newtonian heating and activation energy

Hybrid nanofluids are significant in biomedical, industrial, transportation, as well as several engineering applications due to their high thermal conductivity and mass transfer enhancement nature in contrast to regular fluids and nanofluids. Taking this into consideration, the present problem explores the flow of hybrid nanofluid (Ag − TiO 2/H 2 O) over a stretching cylinder subject to Newtonian heat and mass conditions. The novel aspect of the current work is to analyze the heat and mass transfer characteristics of MHD hybrid nanofluid flow on Darcy-Forchheimer porous medium in addition to activation energy, nonlinear thermal radiation, heat generation/absorption, viscous and Joulian dissipation. Further, Silver (Ag) and Titanium oxide (TiO 2) are the constituent nanoparticles of the water-based hybrid nanofluid owing to their stable chemical features and extensive industrial manufacturing. By introducing suitable similarity transformations, the governing partial differential equations (PDEs) of the developed model are reduced to ordinary differential equations (ODEs), and then the numerical solution is procured with shooting technique by using MATLAB solver bvp4c. The influence of the pertinent parameters is depicted graphically and described elaborately. The analysis indicates that velocity exhibits a declining trend against the permeability and Forchheimer parameters, while the temperature profiles show opposite behavior. The radiation and conjugate heat parameters (R, γ 1) upgrade the heat transfer rate, while the curvature and conjugate mass parameters (α c , γ 2) amplify the mass transfer rate. The maximum heat transfer rate of Ag − TiO 2/H 2 O hybrid nanofluid is 2.3344 attained for γ 1 = 0.6. The investigation demonstrates larger heat and mass transfer rates for Ag − TiO 2/H 2 O hybrid nanofluid than Ag − H 2 O nanofluid. The outcomes of the present investigation have practical applications in conjugate heat transfer over fins, development of vaccines, effluent treatment plants, solar cells, heat exchangers, and many more. An excellent agreement is achieved on comparing our numerical results with the published results in the literature.

Multi‐layer graphene nanosheets bridging binary aluminium oxide for the synergistic enhancement of thermal conductivity and electrical insulation of silicone resin composite

AbstractThe flexible polymer composites usually require high intrinsic thermal conductivity fillers for the applications in thermal management, such as the well‐known graphene, which can, in turn, compromise their electrical insulation properties. Here, the authors developed the silicone resin (SR) composites filled with multi‐layer graphene nanosheets (MGN) and binary alumina (Al2O3), and the microstructure of composites exhibits the dominant skeleton of large‐sized Al2O3 filler and branching of small‐sized Al2O3 fillers features by the size matching effect of optimal binary Al2O3. The introduction of supplementary MGN fillers further increases the face‐to‐face contact probability and bridges the isolated binary Al2O3, which contributes to the high thermal conductivity of 3.0 W·m−1·K−1 under these synergistic effects. The dense and connected ‘Al2O3‐MGN‐Al2O3’ thermal conductive pathway is successfully built, as supported by the numerical simulation and Agari model fitting. Meanwhile, the electrical conductivity caused by MGN can be blocked by the surrounding insulation Al2O3 filler network, exhibiting a high volume resistivity of 1.7 × 1015 Ω · cm. Moreover, the Al2O3/MGN/SR composite films effectively transfer the heat and diminish the hot‐spot temperature by 53.5°C in cooling light emitting diode chip module application.

Thermal conductivity of different materials nanofluids Nanofluids of MXenes, metal organic frameworks, and other Nanostructured materials in heat transfer applications: Review

Nanoparticles display great potential in heat transfer applications due to their impressive thermophysical properties and unique properties, which enhances the performance of a system. This review delves into the thermophysical characteristics of various nanoparticles, including MXenes, MOFs, CNTs, and graphene, and understand the importance of nanoparticles in heat transfer. MXenes are a relatively new nanoparticle that shows a lot of potential in heat transfer applications; yet, when compared to MOFs, the results demonstrated weren't nearly as impressive because of their larger area and pore size. Conversely, the superior heat transfer performance of CNTs and graphene led to their widespread use in various applications. Thermal conductivity enhancements of 30.6, 64, and 64% for MXene, graphene, and MWCNT were observed when nanoparticles were dispersed in water, indicating better heat transfer for CNT and graphene nanoparticles. Nonetheless, even though some displayed better results than others, each nanoparticle is unique and affects the system distinctively. Additionally, in this review, nanoparticles were investigated computationally, and the results were similar to experimental findings, offering further insight into which nanofluids most effectively influence heat transfer. Overall, nanoparticles enhance system efficiency, making nanofluids reliable for diverse processes despite ongoing challenges. However, nanoparticles in many systems are still being discovered and face many challenges. Therefore, future research should try to focus on studying the effects of nanoparticles in new and large-scale applications and seek solutions to the challenges faced by certain nanoparticles to improve these systems.

Influence of curing agent modified BN with different molecular structures on the heat conduction and electrical insulation property of epoxy composites

AbstractBoron nitride (hBN) serves as an outstanding high‐performance polymer organic filler. However, its hexagonal crystal structure renders it chemically inert, thus limiting its applications. This study proposes the modification of hBN using economical amine and anhydride curing agents to reduce aggregation and enhance the heat conduction of epoxy resin. Specifically, the DETA curing agent and methyl tetrahydrophthalic anhydride (MTHPA) curing agent were grafted onto the hBN surface via ball milling and eco‐friendly water scrubbing processes. Subsequently, the modified functionalized BNNS were uniformly dispersed in epoxy resin via a wet process to form composite materials. Results indicate that both modified fillers maintain good dispersion at the epoxy interface. Compared to epoxy resin, the heat conduction of the EP/MTHPA‐BNNS composite material with 10 vol% loading increased by 212%. The EP/DETA‐BNNS composite exhibited a relative thermal conductivity enhancement of 191%. Moreover, both of materials demonstrated significantly improved thermal stability, with slightly reduced breakdown strength. Mechanical property testing revealed a maximum increase of 187.5% in fracture elongation.Highlights Comprehensive study on curing agent modified hBN High dispersion of BNNS after wet ball milling Modified BNNS improves composite interface properties The thermal conductivity increases twice under 10 wt% BNNS loading Composite materials with outstanding electrical insulation and high fracture elongation

Anisotropic Thermal Conductivity Enhancement of the Aligned Metal-Organic Framework under Water Vapor Adsorption.

Metal-organic frameworks (MOFs) exhibit high adsorption and catalytic activities for various gas species. Because gas adsorption can cause a temperature increase in the MOF, which decreases the capacity and adsorption rate, a strict evaluation of its effect on the thermal conductivity of MOFs is essential. In this study, the thermal conductivity measurement of the MOF under water vapor adsorption was performed using an oriented film of copper tetrakis(4-carboxyphenyl)porphyrin (Cu-TCPP) MOF. A recently developed bidirectional 3ω method enabled the anisotropic thermal conductivity measurement of layered Cu-TCPP while maintaining its ordered structure. The water adsorption was found to increase the thermal conductivity in both in-plane and cross-plane directions with different trends and magnitudes, owing to the structural anisotropy. Molecular dynamics simulations suggest that additional vibrational modes provided by the adsorbed water molecules were the reason for the thermal conductivity enhancement.

Enhanced thermal conductivity of reduced graphene oxide reinforced polymer films through a novel GO reduction mechanism

AbstractGraphene's remarkable thermal conductance characteristics makes it a very promising thermal interface material for polymeric composites. In this study, we propose an innovative approach aimed at augmenting the thermal conductivity of flexible composite films, employing reduced graphene oxide (rGO) and polyvinyl alcohol (PVA) as the constituent materials. The fabrication process involves the utilization of solution casting coupled with a low‐temperature chemical reduction method for graphene oxide (GO). Given that the high thermal conductivity of polymer nanocomposites typically correlates with increased crystallinity and reduced defects, our primary objective is to investigate the impact of reduction of GO in order to associate enhance crystallinity within the graphene oxide‐polymer system, with the overall increased thermal conductivity of the resulting GO/PVA films. The diethylene glycol‐GO/PVA films thus, generated through this methodology exhibit an exceptional thermal conductivity of approximately 5.1 W/mK, achieved with a mere 10 wt.% filler loading. This surpasses the thermal conductivity observed in films comprised solely of GO/PVA. The notable enhancement in thermal conductivity can be attributed to several factors, including improved crystallinity and reduced defects of GO with effective polymeric bridging facilitated by the rGO with PVA. Collectively, these advancements contribute to the overall thermal performance of the material, presenting a promising methodology for future developments in the field of thermal conductivity materials.Highlights Reduction of GO through a streamlined and facile methodology. Orchestrated a controlled reduction process at lower temperatures and simultaneously enhancing the crystallinity and decreasing the defects of GO. Fabricated reduced GO/PVA polymer films exhibited an exceptional thermal conductivity of approximately 5.1 W/mK with just a 10 wt.% filler loading.

Interweaved filler network in epoxy resin with reduced interface thermal resistance via in-situ high-temperature “welding” for significantly improved thermal conductivity

For heterogeneous integration in harsh environments, polymeric materials are required to integrate excellent insulating property with significant thermal conductivity. Traditional discrete fillers used in polymeric matrix to create thermal pathways introduce numerous contact interfaces, leading to limited thermal conductivity enhancement efficiency (TCE) and unstable dielectric properties. Here, a distinctive strategy, involving the preparation of an interweaved thermally conductive filler with inherent heat channels through self-templated electrospinning and in-situ high-temperature “interface welding”, is proposed to reduce the interface thermal resistance (ITR). The growth of grains at high temperature facilitates the process of “interface welding”, while self-templated electrospinning establishes intrinsic thermal conduction pathways. Consequently, the epoxy resin fortified with this interweaved filler exhibits an exceptionally TCE of 162.15 % and enhanced in-plane thermal conductivity of 3.75 W m−1 K−1 at ultra-low filler ratio of 7.10 vol%. The combination of high electrical insulation of filler and low filler content results in excellent electrical insulating property (>1017 Ω cm) and stable dielectric properties over a frequency range of 103-106 Hz, enabling the successful implementation of heterogeneous integration in challenging environments. This work has the potential to offer a groundbreaking approach for achieving interconnected functional networks within polymer-based composites.

Synthesis and thermophysical property characterization of aqueous graphene quantum dot dispersions for air-conditioning applications

Air-conditioning systems are on track to demand most of the electricity consumed by buildings around the world. The authors propose that dispersing quantum dots into the chilled water loops of air-conditioners represents a path towards improving the efficiency of air-conditioners. As such, the thermophysical properties of carbon-based quantum dot ‘nanofluids’ (e.g., nanoparticles dispersed in liquids) are presented in this study for sub-ambient temperatures (5–15°C)—an under-explored temperature range which requires understanding for air-conditioning applications. This study also explores dispersion stability and materials compatibility—another under-explored area in the literature which is required for commercial uptake. In this study, carbon quantum dots were synthesized via the hydrothermal route and characterized with UV–Vis, FT-IR, Raman spectroscopy, and TEM. Next, the thermophysical properties of specific heat capacity, thermal conductivity, and viscosity of the nanofluids were experimentally measured between 5 and 15°C (not previously reported for aqueous quantum dots). The highest thermal conductivity enhancement was ∼11% (compared to DI water) for 0.3 wt.% at ∼11 °C. Finally, the stability of the fluid was monitored over time and after exposing the fluids to common materials used in air-conditioning systems (e.g., copper, brass, and stainless steel). Unchanged UV–Vis spectra and the lack of sedimentation indicate that the developed dispersions are indeed suitable for chilled water air-conditioning applications.

Green synthesis, characterization and thermophysical properties of diverse molar Ag decorated GO hybrid nanofluids

The present work critically analyses the thermal characteristics of diverse molar (0.03, 0.06, and 0.09 M) Ag decorated GO hybrid nanofluids at constant 0.05 wt.%. The study broadly encompassed the synthesis, characterization, stability, thermophysical properties, reactivity, and contact angle measurements on copper substrates using varied molar Ag-GO hybrid nanofluids. The thermal impact of these hybrid nanofluids was evaluated across a temperature range of 293–333 K, encompassing thermal conductivity, specific heat, viscosity, surface tension, and density. The results illustrate that increasing the molarity of Ag over GO significantly influenced the thermal properties of the hybrid nanofluids. Notably, the most substantial improvements in thermal conductivity are observed at 333 K, reaching 30.12, 22.63, and 17.13% for 0.09, 0.06, and 0.03 M Ag-GO, respectively, compared to the base fluid. Furthermore, central composite design approach (CCD) was employed to establish correlations between the experimental and predicted thermal conductivity enhancement ratio (K-ratio) results. In conclusion, these studies underscore a promising insight that the optimizing of Ag molarity in GO hybrid nanofluids holds substantial potential for enhancing heat transfer performance across diverse heat transfer applications.

Enhancement of thermal conductivity and abrasion resistance of woody carbon fiber composites via boride catalysis

In order to investigate the effect of boron element on liquefied wood carbon fibers and their composites, boric acid and boron carbide were utilized to modify liquefied wood resin through copolymerization and blending methods respectively. Then boric acid-modified liquefied wood carbon fiber (BA-WCF) and boron carbide-modified liquefied wood carbon fiber (BC-WCF) were produced via melt spinning, curing, and carbonization treatments. As expected, this modification approach effectively prevents the formation of skin-core structures and accelerates the evolution of a graphite microcrystalline structure, thereby enhancing the mechanical properties of the carbon fibers. Particularly, the tensile strength and elongation at break of BA-WCF increased to 331.57 MPa and 7.57 % respectively, representing increments of 117 % and 86 % compared to the conventional fibers. Furthermore, the as-fabricated carbon fiber/resin composites (CFPRs), composing of BA-WCF or BC-WCF as fillers and liquefied wood resin as matrix, exhibited excellent interlaminar shear strength, outstanding abrasion resistance, and well thermal conductivity, as well as electrical performance, significantly outperforming the conventional carbon fiber/phenolic resin composites. The friction rate of BC-WP/BA-WCF/CF was 2.37 %, while its thermal conductivity could reach 1.927 W/(m·K). These promising attributes lay the groundwork for the development of high-performance carbon fiber-based materials, fostering their widespread utilization across various industries.

Investigation on the synergistic effect and thermal properties of poly-hydroxyethyl methacrylate encapsulated graphene quantum dot-paraffin hybrid nanofluid

In this study, a novel water-based hybrid nanofluid was developed using poly-hydroxyethyl methacrylate-encased graphene quantum dot-paraffin nanocomposite (HEMA GQD-P). Graphene quantum dots (GQD) with an average size of 10 to 15 nm were synthesized by citric acid nucleation and the HEMA GQD-P nanocomposites were synthesized by an emulsion polymerization reaction. The emission spectra of GQD obtained using photo-luminescent spectroscopy confirm the occurrence of quantum confinement effect. The synthesis of HEMA GQD-P was carefully carried out to ensure its optimal properties. The synergistic effect due to high thermal conductivity of GQD and high latent heat capacity of paraffin were recognized in the enhanced properties of nanocomposite and hybrid nanofluid. The latent heat capacity of the synthesized nanocomposite was found to be 21.8 % higher than the pure paraffin. The prepared hybrid nanofluid possesses high dispersion stability at pH 7 and the thermal conductivity of the hybrid nanofluid enhances with an increase in nanoparticle concentration. A maximum thermal conductivity enhancement of 53 % (±2) was obtained for the hybrid nanofluid (0.3 vol%) at 30 °C. The present work reveals that the encapsulation of GQD-paraffin in a poly-hydroxyethyl methacrylate shell creates nanocomposites with high heat transfer properties. The synergistic effect of the HEMA GQD-P enhances their potential in the preparation of hybrid nanofluids with enhanced properties for desired thermal management applications.