Through-plane Thermal Conductivity Research Articles

Construction of three-dimensional network using boron nitride microspheres and the thermal conductivity/stability of epoxy resin composites

Efficient heat dissipation has become the focus of electronic packaging materials, constructing three-dimensional thermally conductive filler networks to prepare composites can realize efficient heat transfer. However, there are few studies comparing the effects of different ways of constructing three-dimensional networks on the thermal conductivity enhancement of polymers. In this study, BNMS self-assembled from BNNSs was used as a thermally conductive filler, and the three-dimensional skeleton was constructed by both the powder mixing pressing method and the ice template method, and scanned to analyze the morphological and structural characteristics. At the same time, the epoxy composites were prepared, and the advantages and disadvantages of the thermal conductivity of the composites prepared in different ways were analyzed by combining the SEM structures. In the powder mixing pressing method, the in-plane and through-plane thermal conductivity of the epoxy composites with the BNMS additive amount of 53.92 wt% reached 10.961 W·m−1·K−1 and 9.955 W·m−1·K−1, respectively, which was increased by 58 and 52 times. The thermal stability has been improved significantly that the T60 was in creased by 60.89°C compared to pure epoxy. Using the ice template method with 7.67 wt% of BNMS addition, the through-plane thermal conductivity of the epoxy composites reaches 0.977 W·m−1·K−1, which is an improvement of 428.1 % compared with pure EP. In addition, both composites maintain low dielectric constants and dielectric losses. It is instructive for the preparation method of subsequent construction of three-dimensional thermally conductive filler networks.

Soft and Damping Thermal Interface Materials with Honeycomb-Board-Mimetic Filler Network for Electronic Heat Dissipation.

High-power-density electronic devices under vibrations call for soft and damping thermal interface materials (TIMs) for efficient heat dissipation. However, integrating low hardness, high damping, and superior heat transfer capability into one TIM is highly challenging. Herein, soft, damping, and thermally conductive TIMs are designed and prepared by constructing a honeycomb-board-mimetic boron nitride nanosheet (BNNS) network in a dynamic polyimine via one-step horizontal centrifugal casting. The unique filler network makes the TIMs perform a high through-plane thermal conductivity (> 7.69W m-1 K-1) and a uniform heat transfer process. Meanwhile, the hierarchical dynamic bonding of the polyimine endows the TIMs with low compressive strength (2.16MPa at 20% strain) and excellent damping performance (tan δ > ≈0.3 at 10-2-102Hz). The resulting TIMs also exhibit electrical insulation and remarkable recycling ability. Compared with the commercial ones, the TIMs provide better heat dissipation (4.1°C) for a high-power 5G base station and less temperature fluctuation (1.8°C) for an automotive insulated gate bipolar transistor (IGBT) under vibrations. This rational design offers a viable approach to prepare soft and damping TIMs for effective heat dissipation of high-power-density electronic devices under vibrations.

Thermal conductivity of epoxy composites containing 3D honeycomb boron nitride filler

Polymer matrix composites with excellent thermal management performance have emerged as remarkable materials in the realms of microelectronic devices and wireless communication technologies. However, achieving high thermal conductivity in most composites often requires a high filling load, which will compromise other desirable properties. Herein, utilizing physical foaming and vacuum infiltration methods, we introduce a 3D honeycomb composite consisting of surface-hydroxylated hexagonal boron nitride (OH-BN) and epoxy. The 3D OH-BN honeycomb foam in the composite features a lightweight design (0.33 g/cm3), high strength (7178 times its own weight) and prominent heat transfer performance. Significantly, these composites achieve notable thermal properties, including high through-plane thermal conductivity (2.073 W m−1 K−1) and relatively low thermal resistance (0.995 °C/W) at a reduced filling load (17.2 vol%). In comparison with pure epoxy, the through-plane thermal conductivity is enhanced by an impressive 894 %, while the thermal resistance is reduced to 1/9.4 of that observed in pure epoxy. Besides, the 3D honeycomb composites combine outstanding mechanical performance, low dielectric properties and excellent insulation, underscoring their potential in the field of thermal management applications in microelectronic devices, wireless communication systems and integrated circuits.

Variable orientation in material extrusion of short carbon fiber reinforced polymer composites with high thermal conductivity

Controllable orientation architecture possesses tunable thermal behavior for effective heat dissipation in unidirectional product fields, meanwhile without interference with adjacent components. Herein, we proposed a variable orientation strategy in material extrusion of short carbon fiber (SCF) reinforced polymer composites framework with spatially tunable thermal properties. It was achieved due to the following reasons: (Ⅰ) Inherent shear flow in the nozzle; (Ⅱ) Increasing tensile flow by changing the ratio between the printing speed of monofilament and the feeding speed of filament (Vp/f); (Ⅲ) Further surface tension due to thinning monofilament by varying Vp/f. The SCF with different orientations and content reinforced polyether-ether-ketone (PEEK) composites were successfully fabricated. The microcosmic orientation of SCF could be programmed from a three-layer hierarchical framework to a single-layer oriented framework at different Vp/f. Benefit from variable orientation, the through-plane thermal conductivity of SCF/PEEK composites achieved a thermal conductivity enhancement of 173.9 %. In addition, the simulated application of SCF/PEEK composites in the CPU of the computer showed excellent heat transfer during heating. Further, the thermal conductivity mechanism of the synergistic influence between Vp/f and SCF content was analyzed by cross-sectional microstructure. The proposed strategy in this work for fabricating variable orientation of SCF reinforced polymer composites showcases great application prospects in electronic devices and unidirectional product fields.

Highly thermally conductive composites with boron nitride nanoribbon array

The traditional approaches to fabricate highly thermally conductive yet electrically insulating polymers relies mainly on adding massive ceramic fillers, which not only degrade the mechanical properties of polymers but also introduce more interfaces that lead to more scattering sites for phonons. Thus, it remains a major challenge to achieve high thermal conductivity with low filler content. Herein, to create directional conductors with fewer interfaces, we prepared array of vertically aligned hexagonal boron nitride nanoribbons (BNNRs) and then infused them with polydimethylsiloxane (PDMS). By optimizing the assembly density and crystalline structure of the BNNRs, the BNNR/PDMS composite achieves a remarkable through-plane thermal conductivity of 8.19 W/(m·K) at a low nanoribbon loading of 9.3 wt%, outperforming thermally conductive polymers with insulating fillers in spherical, fibrous, and flaky shapes at similar filler contents. Furthermore, high thermal–mechanical stability and outstanding electrical insulating properties are also discovered. In the thermal interface material (TIM) performance test, the BNNR/PDMS composite exhibits higher cooling efficiency than commercial TIMs, with a decrease in chip temperature of up to 16 °C, and maintains good thermal stability even after continuous heating–cooling processes of as long as 12 h.

Vitrimeric phase change material facilitating 3D-structured boron nitride network for reliable thermal conductive interface materials

Phase change materials (PCMs) shows great promise as thermal interface materials (TIMs) due to their compliance and thermal management properties from solid-liquid phase transition characteristics. However, the significantly reduced thermal conductivity resulting from that randomly dispersed thermal conductive fillers susceptible to localized volume change by solid-liquid phase transition deteriorates the reliable heat transfer of TIM but is often overlooked. In this work, 3D-structured network of boron nitride (BN) fillers is created in vitrimeric PCM (vPCM) consisting of dynamic covalent crosslinked polyolefin elastomer (POE)/paraffin wax (PW) blends. The resulted composites with interconnected BN network show a through-plane thermal conductivity (κ⊥) of 3.08 W m−1 K−1 at 29.8 vol% BN. Significantly, the composites can keep the BN network continuous when heated, and remain κ⊥ of about 1.4 W m−1 K−1 after the solid-liquid phase transition of PW, which ensures reliable heat transfer when achieving thermal management by melting endotherm of PW. Moreover, the composites conform to the surface topography of sandwiching surfaces through solid plasticity under low stress when the crosslinked network rearranges via the exchange of dynamic covalent bonds activated by the melting of POE, reducing the thermal contact resistance. When the composites are used as TIM through thermally triggered reconfigurable package procedures at 80 °C and 50 kPa, the heat dissipation is better than a commercial thermal pad with κ⊥ of 3.86 W m−1 K−1. Vitrimeric PCM facilitates reliable 3D-structured BN network and thermally triggered conformability, paving a promising way for high-performance TIM with excellent heat dissipation.

Compressible thermal interface materials with high through-plane thermal conductivity from vertically oriented carbon fibers

The mechanical properties especially the compression performance are very important for thermal interface materials (TIMs) to mitigate warpage failure caused by stress concentration and reduce contact resistance in practical applications. However, high thermal conductivity and excellent mechanical properties are generally incompatible in traditional TIMs. Herein, we fabricate a high-performance carbon fiber-based TIM by using an extrusion method based on the flow shearing effect. The vertically oriented composite shows a through-plane thermal conductivity up to 18.5 W·m−1·K−1 at 20 wt% carbon fiber content, which is 92.7 times that of pure matrix and 6.3 times that of the random structure. Moreover, the as-prepared material exhibits low hardness of 56 (Shore 00) and outstanding elastic compression performance of 51.4% compression under a pressure of 45 psi. These excellent properties are primarily attributed to the high orientation of the carbon fibers (CFs), thereby establishing a direct and effective thermal conductivity path in the vertical direction. In addition, the synergistic effect of carbon fibers and alumina particles is also beneficial for building thermal conduction pathways. Our work provides an insight to further research in fabricating high-performance flexible TIMs as a promising candidate for applying in advanced thermal management fields.

A Novel Thermal Interface Material Composed of Vertically Aligned Boron Nitride and Graphite Films for Ultrahigh Through-Plane Thermal Conductivity.

The relentless drive toward miniaturization in microelectronic devices has sparked an urgent need for materials that offer both high thermal conductivity (TC) and excellent electrical insulation. Thermal interface materials (TIMs) possessing these dual attributes are highly sought after for modern electronics, but achieving such a combination has proven to be a formidable challenge. In this study, a cutting-edge solution is presented by developing boron nitride (BN) and graphite films layered silicone rubber composites with exceptional TC and electrical insulation properties. Through a carefully devised stacking-cutting method, the high orientation degree of both BN and graphite films is successfully preserved, resulting in an unprecedented through-plane TC of 23.7Wm-1K-1 and a remarkably low compressive modulus of 4.85MPa. Furthermore, the exceptional properties of composites, including low thermal resistance and high resilience rate, make them a reliable and durable option for various applications. Practical tests demonstrate their outstanding heat dissipation performance, significantly reducing CPU temperatures in a computer cooling system. This research work unveils the possible upper limit of TC in BN-based TIMs and paves the way for their large-scale practical implementation, particularly in the thermal management of next-generation electronic devices.

Phase change composites with ultra-high through-plane thermal conductivity achieved by vertically-aligned graphite film and double-shelled microcapsules

The heat dissipation in electronic devices has become bottleneck problem. One of the best solutions is to develop high performance materials which can not only dissipate the heat away, but also absorb heat energy. This kind of double function materials can be obtained by simultaneously using high thermal conductivity (TC) materials and phase change materials. The formation of continuous network of thermally conductive fillers is demonstrated as one of the most effective methods for fabricating highly thermally conductive composites. Here, graphite films (GF) are stacked and vertically cut to endow the composites with high through-plane TC. The obtained composites exhibit a through-plane TC of 51.55 W m−1 K−1 and a low thermal resistance of 0.398 °C cm2 W−1. Besides, double-shelled PDA@SiO2@paraffin (Pa) microcapsules are embedded into the composite to give its good heat-absorption capacity. Via a CPU thermal stress test, the composites demonstrate satisfactory temperature controlling performance.

Stable self-crosslinking phase change composites with vertically aligned boron nitride for high thermal conductivity thermal interface materials

Thermal interface materials (TIMs) must have a high through-plane thermal conductivity in order to efficiently transfer the heat generated by electronic components to heat sinks. Nevertheless, the achievement of high through-plane thermal conductivity is still a great challenge due to the inadequate thermal conductivity network as well as the lack of thermal response from the polymer matrix. Herein, we have developed a solid-solid phase change polymer matrix achieved through self-crosslinking polyethylene glycol (SCPEG). Subsequently, high-performance TIMs based on the SCPEG matrix and vertically aligned boron nitride (BN) nanosheets are obtained by bidirectional freezing, hot pressing, and longitudinal slicing. The prepared BN/SCPEG composites (BN content of 80 vol%) with a vertically oriented network achieved a through-plane thermal conductivity of 23.03 W m-1 K-1. More importantly, the vertically aligned BN nanosheets improve the thermal conductivity of composites, while the SCPEG matrix can reduce the hardness of composites by absorbing the heat, thus decreasing the contact thermal resistance.

Mechanically and Thermally Guided, Honeycomb-like Nanocomposites with Strain-Insensitive High Thermal Conductivity for Stretchable Electronics.

Thermal management materials have become increasingly crucial for stretchable electronic devices and systems. Drastically different from conventional thermally conductive materials, which are applied at static conditions, thermal management materials for stretchable electronics additionally require strain-insensitive thermal conductivity, as they generally undergo cyclic deformation. However, realizing such a property remains challenging mainly because conventional thermally conductive polymer composites generally lack a mechanically guided design. Here, we report a honeycomb-like nanocomposite with a three-dimensional (3D) thermally conductive network fabricated by an arrayed ice-templating technique followed by elastomer infiltration. The hexagonal honeycomb-like structure with thin, compact walls (≈ 40 μm) endows our composite with a high through-plane thermal conductivity (≈ 1.54 W m-1 K-1) at an ultralow boron nitride nanosheet (BNNS) loading (≈ 0.85 vol %), with an enhancement factor of thermal conductivity up to 820% and thermal-insensitive strain up to 200%, which are 2.7 and 2 times higher than those reported in the literature. We report an intelligent strategy for the development of advanced thermal management materials for high-performance stretchable electronics.

Regulated orientation and exfoliation of flaky fillers by close packing structures in polymer composites for excellent thermal conduction and EMI shielding

Efficient heat dissipation and electromagnetic interference (EMI) shielding are essential demands on packaging intensively integrated circuits in advanced electronics. Multicompetent polymer composites with thermal conduction and EMI shielding capacity have attracted tremendous interest in the material science community. Herein, we report the preparation of thermally conductive polymer composites with superior EMI shielding effectiveness (SE) by building a 3D interconnected conductive network under close-packing circumstances. The build of the 3D network relies on the coordinated stacking of flaky and spherical fillers, where the asymmetric graphite flakes (FG) are confined in the interstitial regions of the close-packing structures of hollow glass microspheres (HGμS). The “rigid” close-packing structure of HGμS inhibits the in-plane orientation of FG along the flow direction during melt processing and facilitates the exfoliation of FG under external forces producing a conductive network with enhanced interconnectedness. The model system comprised of thermoplastic polyurethane (TPU), FG and HGμS has attained in-plane and through-plane thermal conductivity of 20.54 W m−1 K−1 and 6.55 W m−1 K−1 with 30 vol% FG (while maintaining a low mass density of 1.15 g cm−3, identical to neat TPU). Meanwhile, a high EMI SE of 69 dB has been achieved at a thickness of 1 mm.

Molecular simulation and experimental investigation of thermal conductivity of flexible graphite film

Flexible graphite film (FGF), as a traditional interface heat dissipation material, has high anisotropy. It is a challenge to enhance both in-plane and through-plane thermal conductivity of FGF. For this reason, the effects of oxygen content, layer spacing, density and particle size on the in-plane and through-plane thermal conductivity of FGF were studied by both molecular simulation and experimental investigation. The simulation results indicate that the ways to improve the thermal conductivity of FGF include reducing oxygen content and layer spacing, increasing the density and matching the size of graphite sheets. The FGF prepared from room temperature exfoliated graphite (RTFGF) has a wide range of adjustable density (1.3–2.0 g/cm3) and thickness (50–400 μm). The thermal conductivity of the RTFGF is significantly improved after heat treatment owing to reduced oxygen content and layer spacing, which is consistent with the simulation results. Moreover, RTFGF with both high in-plane (518 W⋅m−1⋅K−1) and through-plane (7.2 W⋅m−1⋅K−1) thermal conductivity can be obtained by particle size matching of graphite.

Highly thermally conductive and soft thermal interface materials based on vertically oriented boron nitride film

Thermal interface materials (TIMs) with high through-plane thermal conductivity (TC), softness, and electrical insulation are highly desired for modern electronics. However, it is challenging to simultaneously achieve these properties. Boron nitride (BN)-based polymer composites are promising candidates for advanced TIMs owing to the high TC and great electrical insulation of BN. However, previous works perform either low TC (< 8 W m−1 K−1) or high stiffness. The ultimate properties of BN-based TIMs remain largely unclear and unrealized. Here, we fabricate BN film-filled silicone rubber composites by a facile stacking-cutting method, which maintains the high degree of orientation the BN film, so that a record-high though-plane TC of 19.1 W m−1 K−1 and a low compressive modulus of 5.42 MPa are achieved. The low BN content (37 vol%) ensures the softness and resilience of the as-prepared TIMs. This work presents a highly efficient strategy to enhance the performance of BN based TIMs, promoting their large-scale manufacturing and practical applications.

Extreme in-plane thermal conductivity anisotropy in Rhenium-based dichalcogenides

Anisotropies in thermal conductivity are important for thermal management in a variety of applications, but also provide insight on the physics of nanoscale heat transfer. As materials are discovered with more extreme transport properties, it is interesting to ask what the limits are for how dissimilar the thermal conductivity can be along different directions in a crystal. Here we report on the thermal properties of rhenium-based transition metal dichalcogenides (TMDs), specifically rhenium disulfide (ReS2) and rhenium diselenide (ReSe2), highlighting their extraordinary thermal conductivity anisotropy. Along the basal crystal plane of ReS2, a maximum of 169±11 W mK−1 is detected along the b-axis and a minimum of 53±4 W mK−1 perpendicular to it. For ReSe2, the maximum and minimum values of 116±3 W mK−1 and 27±1 W mK−1 are found to lie 60° and 150° away from the b-axis, along the polarization direction of some of the principal Raman modes. These measurements demonstrate a remarkable anisotropy of 3.2 × and 4.3 × in the conductivity within the crystal basal planes, respectively. The through-plane thermal conductivities, recorded at 0.66±0.01 W mK−1 for ReS2 and 2.31±0.01 W mK−1 for ReSe2, highlight the impact of their layered structures, contributing to notably high in-plane to through-plane thermal conductivity ratios of 256 × for ReS2 and 50 × for ReSe2. This research demonstrates the unique thermal properties that these comparatively underexplored TMDs have, shedding light on the need for further exploration into the intricate thermal behavior of such materials, while underscoring their potential significance for future applications in the fields of semiconductor devices and nanotechnology.

Superior corrosion resistance and thermal/electro properties of graphene−epoxy composite coating on Mg alloy with biomimetic interface and orientation

Biomimetic graphene−epoxy composite coating was fabricated with a “brick and mud” structure via a spin-coating strategy. Imidazolium-based ionic liquids modified graphene (GI) was synthesized to improve the interfacial compatibility between the graphene (G) layers and epoxy resin. The surface morphology and chemical structures were observed and analyzed through scanning electron microscopy (FE-SEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) as well as Fourier transform infrared spectroscopy (FTIR). The thermal imager was used to record the temperature change on the surface. The surface resistivity and thermal conductivity of the coating were determined via volumetric surface area resistivity tester and laser flash method, respectively. The corrosion resistance was investigated through electrochemical impedance spectroscopy (EIS) and salt spray testing. The GI layers in the composite coating exhibited a near-parallel orientation, which led to improved heat transfer and electrostatic dissipative efficiency. The through-plane thermal conductivity and surface resistivity were 0.77 W·m−1·K−1 and 1.6×106 Ω·cm, respectively. Electrochemical impedance spectroscopy tests revealed that the low-frequency modulus of the coating reached 6.76×1010 Ω·cm2 after 40 d of immersion, which was about two orders of the magnitude higher than that of the pure epoxy coating, showing a superior corrosion resistance.

Dressing Paraffin Wax/Boron Nitride Phase Change Composite with a Polyethylene "Underwear" for the Reliable Battery Safety Management.

Phase change material (PCM) can provide a battery system with a buffer platform to respond to thermal failure problems. However, current PCMs through compositing inorganics still suffer from insufficient thermal-transport behavior and safety reliability against external force. Herein, a best-of-both-worlds method is reported to allow the PCM out of this predicament. It is conducted by combining a traditional PCM (i.e., paraffin wax/boron nitride) with a spirally weaved polyethylene fiber fabric, just like the traditional PCM is wearing functional underwear. On the one hand, the spirally continuous thermal pathways of polyethylene fibers in the fabric collaborate with the boron nitride network in the PCM, enhancing the through-plane and in-plane thermal conductivity to 10.05 and 7.92Wm-1 K, respectively. On the other, strong polyethylene fibers allow the PCM to withstand a high puncture strength of 47.13 N and tensile strength of 18.45MPa although above the phase transition temperature. After this typical PCM packs a triple Li-ion battery system, the battery can be promised reliable safety management against both thermal and mechanical abuse. An obvious temperature drop of >10°C is observed in the battery electrode during the cycling charging and discharging process.

Tree-ring structured phase change materials with high through-plane thermal conductivity and flexibility for advanced thermal management

Phase change materials (PCMs) as one of the most promising latent heat storage materials have been applied for thermal management of electronic devices. Nonetheless, simultaneously endowing PCMs with high through-plane thermal conductivity and flexibility remains challenging. Herein, a coupling strategy combining scraping, hot compression, and roll-cutting is proposed to fabricate polydimethylsiloxane/paraffin/boron nitride (PDMS/PW/BN) composites. The BN alignment across the in-plane (x-y direction) was firstly obtained via scraping, then hot compression and roll-cutting were introduced to induce BN aligned across the through-plane (z-direction). Consequently, PW was wrapped by the cross-linked PDMS/BN network, thus forming a similar tree-ring structure to natural wood. The tree-ring structure effectively avoided the liquid leakage of PW, thus showing a high dimension retention ratio of 98 %. The vertical orientation of the BN network imparted the PCMs improved through-plane thermal conductivity of the PCMs to 2.16 W·m−1·K−1 at a BN loading of 13.0 wt%, showing a remarkable improvement of 943 % in comparison with PDMS/PW. Interestingly, the PCMs exhibited tunable thermal conductivity by triggering the melting-crystallization transition of PW. The in-situ X-ray diffraction indicated that the BN network rearrangement occurred during the phase transition. Furthermore, the good thermal management capability of PCMs was practically confirmed on working chips and via finite element simulation. This work presents a cost-effective approach for producing flexible PCMs with high through-plane thermal conductivity, which have the potential to be used in the thermal management of advanced electronics.

Improving thermal conductivity of graphene films with assistance of melamine

Due to the high degree of integration and high-power-density, excessive heat accumulation significantly endangers the performance of electronics. Therefore, developing high-performance thermal interface materials has become particularly vital for ensuring the regular operation of the electronics. Graphene-based materials attract great attention due to graphene’s intrinsic excellent thermal conductivity. However, the internal defects in graphene and the lack of interlayer heat conduction pathways between graphene microsheets dramatically reduce the thermal conductivity of graphene-based materials. Herein, melamine is used to improve the thermal properties of graphene films prepared by thermal reduction of graphene oxide (GO) microsheets. With an addition of 3 wt% of melamine, the in-plane and through-plane thermal conductivities of the graphene films with a thickness of 35 μm reach 1.32 × 103 and 5.09 W m−1 K−1, respectively. This is likely due to the covalent connection of graphene microsheets through amide structure formed by the chemical reaction between melamine and GOs, and the remedy of defects in graphene by nitrogen doping with the assistance of high-temperature annealing. The operation temperature of LED is greatly reduced, when the prepared graphene films is used as thermal interface material, compared to other commercial products. The results provide a promising way to improve the thermal properties of graphene films, which is of great significance for various applications, such as thermal management for high-power-density electronics.

Thin paints for durable and scalable radiative cooling

Passive daytime radiative cooling (PDRC) is environment-friendly without energy input by enhancing the coating’s solar reflectance (R¯solar) and thermal emittance (ε¯LWIR) in the atmosphere’s long-wave infrared transmission window. However, high R¯solar is usually achieved by increasing the coating’s thickness, which not only increases materials’ cost but also impairs heat transfer. Additionally, the desired high R¯solar is vulnerable to dust pollution in the outdoors. In this work, a thin paint was designed by mixing hBN plates, PFOTS, and IPA.R¯solar = 0.963 andε¯LWIR = 0.927 was achieved at a thickness of 150 μm due to the high backscattering ability of scatters. A high through-plane thermal conductivity (∼1.82 W m−1 K−1) also can be obtained. In addition, the porous structure coupled with the binder PFOTS resulted in a contact angle of 154°, demonstrating excellent durability under dust contamination. Outdoor experiments showed that the thin paint can obtain a 2.3 °C lower temperature for sub-ambient cooling than the reference PDRC coating in the daytime. Furtherly, the above-ambient heat dissipation performance can be enhanced by spraying the thin paint on a 3D heat sink, which was 15.7 °C lower than the reference 1D structure, demonstrating excellent performance for durable and scalable PDRC applications.