Using a walnut shellas a carbon source and ZnCl_2 as an activating agent,we resolved the temperature gradient problems of activated carbon in the microwave desorption process.An appropriate amount of silicon carbide w...Using a walnut shellas a carbon source and ZnCl_2 as an activating agent,we resolved the temperature gradient problems of activated carbon in the microwave desorption process.An appropriate amount of silicon carbide was added to prepare the composite activated carbon with high thermalconductivity while developing VOC adsorption-microwave regeneration technology.The experimentalresults show that the coefficient of thermalconductivity of SiC-AC is three times as much as those of AC and SY-6.When microwave power was 480 W in its microwave desorption,the temperature of the bed thermaldesorption was 10 ℃ to 30 ℃ below that of normalactivated carbon prepared in our laboratory.The toluene desorption activation energy was 16.05 k J·mol^(-1),which was 15% less than the desorption activation energy of commercialactivated carbon.This study testified that the process could maintain its high adsorption and regeneration desorption performances.展开更多
High thermal conductivity dense silica bricks have the higher thermal conductivity than ordinary silica bricks,which is conducive to the realization of energy saving and emission reduction in the iron and steel indust...High thermal conductivity dense silica bricks have the higher thermal conductivity than ordinary silica bricks,which is conducive to the realization of energy saving and emission reduction in the iron and steel industry.The performance of ordinary silica bricks and high thermal conductivity dense silica bricks was compared,and the high thermal conductivity mechanism was analyzed.The results show that(1)compared with ordinary silica bricks,high thermal conductivity dense silica bricks have the characteristics of higher thermal conductivity,lower apparent porosity,higher tridymite content,higher compressive strength,and higher thermal expansion;(2)by increasing the tridymite content and reducing the porosity,the close packing of honeycombα-tridymite improves the density and continuity of the SiO_(2)frame structure of the silica bricks,and the larger area perpendicular to the heat transfer direction improves the thermal conductivity of the bricks;(3)the densification of the silica bricks also increases the thermal expansion of the bricks,but they still meet the standard requirements.展开更多
Highly thermally conductive graphitic film(GF)materials have become a competitive solution for the thermal management of high-power electronic devices.However,their catastrophic structural failure under extreme altern...Highly thermally conductive graphitic film(GF)materials have become a competitive solution for the thermal management of high-power electronic devices.However,their catastrophic structural failure under extreme alternating thermal/cold shock poses a significant challenge to reliability and safety.Here,we present the first investigation into the structural failure mechanism of GF during cyclic liquid nitrogen shocks(LNS),which reveals a bubbling process characterized by“permeation-diffusion-deformation”phenomenon.To overcome this long-standing structural weakness,a novel metal-nanoarmor strategy is proposed to construct a Cu-modified graphitic film(GF@Cu)with seamless heterointerface.This well-designed interface ensures superior structural stability for GF@Cu after hundreds of LNS cycles from 77 to 300 K.Moreover,GF@Cu maintains high thermal conductivity up to 1088 W m^(−1)K^(−1)with degradation of less than 5%even after 150 LNS cycles,superior to that of pure GF(50%degradation).Our work not only offers an opportunity to improve the robustness of graphitic films by the rational structural design but also facilitates the applications of thermally conductive carbon-based materials for future extreme thermal management in complex aerospace electronics.展开更多
Composites that can rapidly self-healing their structure and function at room temperature have broad application prospects.However,in view of the complexity of composite structure and composition,its self-heal is faci...Composites that can rapidly self-healing their structure and function at room temperature have broad application prospects.However,in view of the complexity of composite structure and composition,its self-heal is facing challenges.In this article,supramolecular effect is proposed to repair the multistage structure,mechanical and thermal properties of composite materials.A stiff and tough supramolecular frameworks of 2-[[(butylamino)carbonyl]oxy]ethyl ester(PBA)–polydimethylsiloxane(PDMS)were established using a chain extender with double amide bonds in a side chain to extend prepolymers through copolymerization.Then,by introducing the copolymer into a folded graphene film(FGf),a highly thermally conductive composite of PBA–PDMS/FGf with self-healing capacity was fabricated.The ratio of crosslinking and hydrogen bonding was optimized to ensure that PBA–PDMS could completely self-heal at room temperature in 10 min.Additionally,PBA–PDMS/FGf exhibits a high tensile strength of 2.23±0.15 MPa at break and high thermal conductivity of 13±0.2 W m^(−1)K^(−1);of which the self-healing efficiencies were 100%and 98.65%at room temperature for tensile strength and thermal conductivity,respectively.The excellent self-healing performance comes from the efficient supramolecular interaction between polymer molecules,as well as polymer molecule and graphene.This kind of thermal conductive self-healing composite has important application prospects in the heat dissipation field of next generation electronic devices in the future.展开更多
The nitrogen dimer as both a fundamental building unit in designing a new type of nitrides, and a material gene associated with high electrical and thermal conductivities is investigated by first principles calculatio...The nitrogen dimer as both a fundamental building unit in designing a new type of nitrides, and a material gene associated with high electrical and thermal conductivities is investigated by first principles calculations.The results indicate that the predicted Si N4 is structurally stable and reasonably energy-favored with a striking feature in its band structure that exhibits free electron-like energy dispersions. It possesses a high electrical conductivity(5.07 × 10^5 S/cm) and a high thermal conductivity(371 W/m·K) comparable to copper. The validity is tested by isostructural Al N4 and Si C4. It is demonstrated that the nitrogen dimers can supply a high density of delocalized electrons in this new type of nitrides.展开更多
The exponentially increasing heat generation in electronic devices,induced by high power density and miniaturization,has become a dominant issue that affects carbon footprint,cost,performance,reliability,and lifespan....The exponentially increasing heat generation in electronic devices,induced by high power density and miniaturization,has become a dominant issue that affects carbon footprint,cost,performance,reliability,and lifespan.Liquid metals(LMs)with high thermal conductivity are promising candidates for effective thermal management yet are facing pump-out and surface-spreading issues.Confinement in the form of metallic particles can address these problems,but apparent alloying processes elevate the LM melting point,leading to severely deteriorated stability.Here,we propose a facile and sustainable approach to address these challenges by using a biogenic supramolecular network as an effective diffusion barrier at copper particle-LM(EGaIn/Cu@TA)interfaces to achieve superior thermal conduction.The supramolecular network promotes LM stability by reducing unfavorable alloying and fluidity transition.The EGaIn/Cu@TA exhibits a record-high metallic-mediated thermal conductivity(66.1 W m^(-1) K^(-1))and fluidic stability.Moreover,mechanistic studies suggest the enhanced heat flow path after the incorporation of copper particles,generating heat dissipation suitable for computer central processing units,exceeding that of commercial silicone.Our results highlight the prospects of renewable macromolecules isolated from biomass for the rational design of nanointerfaces based on metallic particles and LM,paving a new and sustainable avenue for high-performance thermal management.展开更多
Epoxy resins with a high dielectric constant and low intrinsic thermal conductivity coefficient cannot meet the current application requirements of advanced electronic and electrical equipment.Therefore,novel fluorine...Epoxy resins with a high dielectric constant and low intrinsic thermal conductivity coefficient cannot meet the current application requirements of advanced electronic and electrical equipment.Therefore,novel fluorine-containing liquid crystal epoxy compounds(TFSAEy)with fluorinated groups,biphenyl units,and flexible alkyl chains are first synthesized via amidation and esterification reactions.Then,4,4′-diaminodiphenylmethane(DDM)is used as a curing agent to prepare the corresponding fluorine-containing liquid crystal epoxy resins.The obtained dielectric constant(ε)and dielectric loss(tanδ)values of TFSAEy/DDM at 1 MHz are 2.54 and 0.025,respectively,which are significantly lower than those of conventional epoxy resins(E-51/DDM,3.52 and 0.038).Additionally,the intrinsic thermal conductivity coefficient(λ)of TFSAEy/DDM is 0.36 W/(m⋅K),71.4%higher than that of E-51/DDM(0.21 W/(m⋅K)).Meanwhile,the corresponding elastic modulus,hardness,glass transition temperature,and heat resistance index of TFSAEy/DDM are 5.73 GPa,0.35 GPa,213.5◦C,and 188.7℃,respectively,all superior to those of E-51/DDM(3.68 GPa,0.27 GPa,107.2℃,and 174.8℃),presenting potential application in high-heating electronic component packaging and printed circuit boards.展开更多
High-thermal-conductivity silicon nitride ceramic substrates are indispensable components for nextgeneration high-power electronic devices because of their excellent mechanical properties and high thermal conductiviti...High-thermal-conductivity silicon nitride ceramic substrates are indispensable components for nextgeneration high-power electronic devices because of their excellent mechanical properties and high thermal conductivities, which make them suitable for applications in complex and extreme environments. Here, we present an overview of the recent developments in the preparation of high-thermal-conductivity silicon nitride ceramics. First,the factors affecting the thermal conductivity of silicon nitride ceramics are described. These include lattice oxygen and grain boundary phases, as well the oxygen content of the crystal lattice, which is the main influencing factor.Then, the methods to prepare high-thermal-conductivity silicon nitride ceramics are presented. Recent work on the preparation of high-thermal-conductivity silicon nitride is described in detail, including the raw materials used and the forming and sintering processes. Although great progress has been made, the development of a high-quality,low-cost fabrication process remains a challenge. Nevertheless, we believe that high-thermal-conductivity silicon nitride substrates are promising for massive practical applications in the next generation of high-power electronic devices.展开更多
With the packing density growing continuously in integrated electronic devices,sufficient heat dissipation becomes a serious challenge.Recently,dielectric materials with high thermal conductivity have brought insight ...With the packing density growing continuously in integrated electronic devices,sufficient heat dissipation becomes a serious challenge.Recently,dielectric materials with high thermal conductivity have brought insight into effective dissipation of waste heat in electronic devices to prevent them from overheating and guarantee the performance stability.Layered CrOCl,an antiferromagnetic insulator with low-symmetry crystal structure and atomic level flatness,might be a promising solution to the thermal challenge.Herein,we have systematically studied the thermal transport of suspended few-layer CrOCl flakes by microRaman thermometry.The CrOCl flakes exhibit high thermal conductivities along zigzag direction,from~392±33 to~1,017±46 W·m^(−1)·K^(−1) with flake thickness from 2 to 50 nm.Besides,pronounced thickness-dependent thermal conductivity ratio(/from~2.8±0.24 to~4.3±0.25)has been observed in the CrOCl flakes,attributed to the discrepancy of phonon dispersion and phonon surface scattering.As a demonstration to the heat sink application of layered CrOCl,we then investigate the energy dissipation in graphene devices on CrOCl,SiO_(2) and hexagonal boron nitride(h-BN)substrates,respectively.The graphene device temperature rise on CrOCl is only 15.4%of that on SiO_(2) and 30%on h-BN upon the same electric power density,indicating the efficient heat dissipation of graphene device on CrOCl.Our study provides new insights into two-dimentional(2D)dielectric material with high thermal conductivity and strong anisotropy for the application of thermal management in electronic devices.展开更多
With the increasing integration level of modern electronics,thermal management becomes an urgent issue for guaranteeing the work efficiency and lifespan of electronics.On the basis of intrinsic high thermal conductivi...With the increasing integration level of modern electronics,thermal management becomes an urgent issue for guaranteeing the work efficiency and lifespan of electronics.On the basis of intrinsic high thermal conductivity nature,highly ordered graphite and copper stripes are densely aligned in the silicone gel pads in vertical(VCuGr)and oblique(@15°CuGr)directions to couple the high thermal conductivity and mechanical softness.The wetting nature of liquid metal(LM)on the chemically treated Cu surface is utilized to form a LM layer on the two surfaces of thermal pads.The obtained LM-pad TIMs possessed ultrahigh through-plane thermal conductivity(VCuGr:71.4 W/(m K),@15°CuGr:62.5 W/(m K))under the normal packaging pressure.The thermal resistance decreased from 0.69 cm^(2) K/W to 0.25 cm^(2) K/W with the surface modification with LM.Theoretical simulation and practical thermal dissipation test results further demonstrate the excellent thermal management capability of these composites in high-power electronics.展开更多
Polymer-dispersed liquid crystal(PDLC)films comprising polyvinyl alcohol(PVA)and liquid crystal monomer(LCM)were successfully obtained by the method of solution casting&thermal compressing.LCM was distributed orde...Polymer-dispersed liquid crystal(PDLC)films comprising polyvinyl alcohol(PVA)and liquid crystal monomer(LCM)were successfully obtained by the method of solution casting&thermal compressing.LCM was distributed orderly in PVA matrix by hydrogen bond interaction,to form PVA-LCM interpe net rating-layered networks.When the mass fraction of LCM was up to 35 wt%,the corresponding in-plane thermal conductivity coefficient(λ//)of PDLC film was significantly increased to 1.41 W m^(-1)K^(-1),about 10.8 times that of neat PVA(0.13 W m^(-1)K^(-1)).High intrinsicλ//values of PDLC films were mainly attributed to the formed microscopic-ordered structures from ordered stacking of LCM,ordered arrangement of PVA chains,and their hydrogen bond interaction.This work would offer a new way to design and prepare novel intrinsic high thermal conductive polymers.展开更多
基金Funded by the National High Technology Research and Development Program of China("863"Program)(No.2006AA06A310)
文摘Using a walnut shellas a carbon source and ZnCl_2 as an activating agent,we resolved the temperature gradient problems of activated carbon in the microwave desorption process.An appropriate amount of silicon carbide was added to prepare the composite activated carbon with high thermalconductivity while developing VOC adsorption-microwave regeneration technology.The experimentalresults show that the coefficient of thermalconductivity of SiC-AC is three times as much as those of AC and SY-6.When microwave power was 480 W in its microwave desorption,the temperature of the bed thermaldesorption was 10 ℃ to 30 ℃ below that of normalactivated carbon prepared in our laboratory.The toluene desorption activation energy was 16.05 k J·mol^(-1),which was 15% less than the desorption activation energy of commercialactivated carbon.This study testified that the process could maintain its high adsorption and regeneration desorption performances.
文摘High thermal conductivity dense silica bricks have the higher thermal conductivity than ordinary silica bricks,which is conducive to the realization of energy saving and emission reduction in the iron and steel industry.The performance of ordinary silica bricks and high thermal conductivity dense silica bricks was compared,and the high thermal conductivity mechanism was analyzed.The results show that(1)compared with ordinary silica bricks,high thermal conductivity dense silica bricks have the characteristics of higher thermal conductivity,lower apparent porosity,higher tridymite content,higher compressive strength,and higher thermal expansion;(2)by increasing the tridymite content and reducing the porosity,the close packing of honeycombα-tridymite improves the density and continuity of the SiO_(2)frame structure of the silica bricks,and the larger area perpendicular to the heat transfer direction improves the thermal conductivity of the bricks;(3)the densification of the silica bricks also increases the thermal expansion of the bricks,but they still meet the standard requirements.
基金the National Natural Science Foundation of China(Nos.52272046,52090030,52090031,52122301,51973191)the Natural Science Foundation of Zhejiang Province(LR23E020003)+4 种基金Shanxi-Zheda Institute of New Materials and Chemical Engineering(2021SZ-FR004,2022SZ-TD011,2022SZ-TD012,2022SZ-TD014)Hundred Talents Program of Zhejiang University(188020*194231701/113,112300+1944223R3/003,112300+1944223R3/004)the Fundamental Research Funds for the Central Universities(Nos.226-2023-00023,226-2023-00082,2021FZZX001-17,K20200060)National Key R&D Program of China(NO.2022YFA1205300,NO.2022YFA1205301,NO.2020YFF0204400,NO.2022YFF0609801)“Pioneer”and“Leading Goose”R&D Program of Zhejiang 2023C01190.
文摘Highly thermally conductive graphitic film(GF)materials have become a competitive solution for the thermal management of high-power electronic devices.However,their catastrophic structural failure under extreme alternating thermal/cold shock poses a significant challenge to reliability and safety.Here,we present the first investigation into the structural failure mechanism of GF during cyclic liquid nitrogen shocks(LNS),which reveals a bubbling process characterized by“permeation-diffusion-deformation”phenomenon.To overcome this long-standing structural weakness,a novel metal-nanoarmor strategy is proposed to construct a Cu-modified graphitic film(GF@Cu)with seamless heterointerface.This well-designed interface ensures superior structural stability for GF@Cu after hundreds of LNS cycles from 77 to 300 K.Moreover,GF@Cu maintains high thermal conductivity up to 1088 W m^(−1)K^(−1)with degradation of less than 5%even after 150 LNS cycles,superior to that of pure GF(50%degradation).Our work not only offers an opportunity to improve the robustness of graphitic films by the rational structural design but also facilitates the applications of thermally conductive carbon-based materials for future extreme thermal management in complex aerospace electronics.
基金financially supported by National Natural Science Foundation of China (Grant Nos. 52173078, 52130303, 51973158, 51803151, and 51973152)the Science Foundation for Distinguished Young Scholars in Tianjin (No. 19JCJQJC61700)Tianjin Postgraduate Scientific Research Innovation Project in 2019 (2019YJSB181)
文摘Composites that can rapidly self-healing their structure and function at room temperature have broad application prospects.However,in view of the complexity of composite structure and composition,its self-heal is facing challenges.In this article,supramolecular effect is proposed to repair the multistage structure,mechanical and thermal properties of composite materials.A stiff and tough supramolecular frameworks of 2-[[(butylamino)carbonyl]oxy]ethyl ester(PBA)–polydimethylsiloxane(PDMS)were established using a chain extender with double amide bonds in a side chain to extend prepolymers through copolymerization.Then,by introducing the copolymer into a folded graphene film(FGf),a highly thermally conductive composite of PBA–PDMS/FGf with self-healing capacity was fabricated.The ratio of crosslinking and hydrogen bonding was optimized to ensure that PBA–PDMS could completely self-heal at room temperature in 10 min.Additionally,PBA–PDMS/FGf exhibits a high tensile strength of 2.23±0.15 MPa at break and high thermal conductivity of 13±0.2 W m^(−1)K^(−1);of which the self-healing efficiencies were 100%and 98.65%at room temperature for tensile strength and thermal conductivity,respectively.The excellent self-healing performance comes from the efficient supramolecular interaction between polymer molecules,as well as polymer molecule and graphene.This kind of thermal conductive self-healing composite has important application prospects in the heat dissipation field of next generation electronic devices in the future.
基金Supported by the National Natural Science Foundation of China under Grant Nos 51532010,91422303,51672306 and 51772322the National Key Research and Development Program of China under Grant No 2016YFA0300604+1 种基金the Beijing Municipal Science&Technology Commission under Grant No Z161100002116018the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No XDB07020100
文摘The nitrogen dimer as both a fundamental building unit in designing a new type of nitrides, and a material gene associated with high electrical and thermal conductivities is investigated by first principles calculations.The results indicate that the predicted Si N4 is structurally stable and reasonably energy-favored with a striking feature in its band structure that exhibits free electron-like energy dispersions. It possesses a high electrical conductivity(5.07 × 10^5 S/cm) and a high thermal conductivity(371 W/m·K) comparable to copper. The validity is tested by isostructural Al N4 and Si C4. It is demonstrated that the nitrogen dimers can supply a high density of delocalized electrons in this new type of nitrides.
基金National Talents ProgramNational Natural Science Foundation of China,Grant/Award Numbers:22108181,22178233+4 种基金Talents Program of Sichuan ProvinceDouble First-Class University Plan of Sichuan UniversityState Key Laboratory of Polymer Materials Engineering,Grant/Award Number:sklpme 2020-03-01Sichuan Science and Technology Program,Grant/Award Number:2022YFN0070The Sichuan Province Postdoctoral Special Funding。
文摘The exponentially increasing heat generation in electronic devices,induced by high power density and miniaturization,has become a dominant issue that affects carbon footprint,cost,performance,reliability,and lifespan.Liquid metals(LMs)with high thermal conductivity are promising candidates for effective thermal management yet are facing pump-out and surface-spreading issues.Confinement in the form of metallic particles can address these problems,but apparent alloying processes elevate the LM melting point,leading to severely deteriorated stability.Here,we propose a facile and sustainable approach to address these challenges by using a biogenic supramolecular network as an effective diffusion barrier at copper particle-LM(EGaIn/Cu@TA)interfaces to achieve superior thermal conduction.The supramolecular network promotes LM stability by reducing unfavorable alloying and fluidity transition.The EGaIn/Cu@TA exhibits a record-high metallic-mediated thermal conductivity(66.1 W m^(-1) K^(-1))and fluidic stability.Moreover,mechanistic studies suggest the enhanced heat flow path after the incorporation of copper particles,generating heat dissipation suitable for computer central processing units,exceeding that of commercial silicone.Our results highlight the prospects of renewable macromolecules isolated from biomass for the rational design of nanointerfaces based on metallic particles and LM,paving a new and sustainable avenue for high-performance thermal management.
基金Foundation ofNational Natural Science Foundation of China,Grant/Award Number:51973173+3 种基金Fundamental Research Funds for the Central UniversitiesUndergraduate Innovation and Business Program in Northwestern Polytechnical UniversityInnovation Foundation for Doctor’s Dissertation of Northwestern Polytechnical University,Grant/Award Number:CX2023026Polymer Electromagnetic Functional Materials Innovation Team of Shaanxi Sanqin Scholars。
文摘Epoxy resins with a high dielectric constant and low intrinsic thermal conductivity coefficient cannot meet the current application requirements of advanced electronic and electrical equipment.Therefore,novel fluorine-containing liquid crystal epoxy compounds(TFSAEy)with fluorinated groups,biphenyl units,and flexible alkyl chains are first synthesized via amidation and esterification reactions.Then,4,4′-diaminodiphenylmethane(DDM)is used as a curing agent to prepare the corresponding fluorine-containing liquid crystal epoxy resins.The obtained dielectric constant(ε)and dielectric loss(tanδ)values of TFSAEy/DDM at 1 MHz are 2.54 and 0.025,respectively,which are significantly lower than those of conventional epoxy resins(E-51/DDM,3.52 and 0.038).Additionally,the intrinsic thermal conductivity coefficient(λ)of TFSAEy/DDM is 0.36 W/(m⋅K),71.4%higher than that of E-51/DDM(0.21 W/(m⋅K)).Meanwhile,the corresponding elastic modulus,hardness,glass transition temperature,and heat resistance index of TFSAEy/DDM are 5.73 GPa,0.35 GPa,213.5◦C,and 188.7℃,respectively,all superior to those of E-51/DDM(3.68 GPa,0.27 GPa,107.2℃,and 174.8℃),presenting potential application in high-heating electronic component packaging and printed circuit boards.
基金financially supported by the National Key Research and Development Program of China (No.2017YFB0310400)the National Natural Science Foundation of China (No.51427802)。
文摘High-thermal-conductivity silicon nitride ceramic substrates are indispensable components for nextgeneration high-power electronic devices because of their excellent mechanical properties and high thermal conductivities, which make them suitable for applications in complex and extreme environments. Here, we present an overview of the recent developments in the preparation of high-thermal-conductivity silicon nitride ceramics. First,the factors affecting the thermal conductivity of silicon nitride ceramics are described. These include lattice oxygen and grain boundary phases, as well the oxygen content of the crystal lattice, which is the main influencing factor.Then, the methods to prepare high-thermal-conductivity silicon nitride ceramics are presented. Recent work on the preparation of high-thermal-conductivity silicon nitride is described in detail, including the raw materials used and the forming and sintering processes. Although great progress has been made, the development of a high-quality,low-cost fabrication process remains a challenge. Nevertheless, we believe that high-thermal-conductivity silicon nitride substrates are promising for massive practical applications in the next generation of high-power electronic devices.
基金supported by the National Natural Science Foundation of China(No.11874423).
文摘With the packing density growing continuously in integrated electronic devices,sufficient heat dissipation becomes a serious challenge.Recently,dielectric materials with high thermal conductivity have brought insight into effective dissipation of waste heat in electronic devices to prevent them from overheating and guarantee the performance stability.Layered CrOCl,an antiferromagnetic insulator with low-symmetry crystal structure and atomic level flatness,might be a promising solution to the thermal challenge.Herein,we have systematically studied the thermal transport of suspended few-layer CrOCl flakes by microRaman thermometry.The CrOCl flakes exhibit high thermal conductivities along zigzag direction,from~392±33 to~1,017±46 W·m^(−1)·K^(−1) with flake thickness from 2 to 50 nm.Besides,pronounced thickness-dependent thermal conductivity ratio(/from~2.8±0.24 to~4.3±0.25)has been observed in the CrOCl flakes,attributed to the discrepancy of phonon dispersion and phonon surface scattering.As a demonstration to the heat sink application of layered CrOCl,we then investigate the energy dissipation in graphene devices on CrOCl,SiO_(2) and hexagonal boron nitride(h-BN)substrates,respectively.The graphene device temperature rise on CrOCl is only 15.4%of that on SiO_(2) and 30%on h-BN upon the same electric power density,indicating the efficient heat dissipation of graphene device on CrOCl.Our study provides new insights into two-dimentional(2D)dielectric material with high thermal conductivity and strong anisotropy for the application of thermal management in electronic devices.
基金This work was financially supported by the National Natural Science Foundation of China(Grant Nos.11204097 and U1530120).
文摘With the increasing integration level of modern electronics,thermal management becomes an urgent issue for guaranteeing the work efficiency and lifespan of electronics.On the basis of intrinsic high thermal conductivity nature,highly ordered graphite and copper stripes are densely aligned in the silicone gel pads in vertical(VCuGr)and oblique(@15°CuGr)directions to couple the high thermal conductivity and mechanical softness.The wetting nature of liquid metal(LM)on the chemically treated Cu surface is utilized to form a LM layer on the two surfaces of thermal pads.The obtained LM-pad TIMs possessed ultrahigh through-plane thermal conductivity(VCuGr:71.4 W/(m K),@15°CuGr:62.5 W/(m K))under the normal packaging pressure.The thermal resistance decreased from 0.69 cm^(2) K/W to 0.25 cm^(2) K/W with the surface modification with LM.Theoretical simulation and practical thermal dissipation test results further demonstrate the excellent thermal management capability of these composites in high-power electronics.
基金support from the National Natural Science Foundation of China(51903207 and 51773169)Guangdong Basic and Applied Basic Research Foundation(2019B1515120093)+3 种基金Natural Science Basic Research Plan for Distinguished Young Scholars in Shaanxi Province(2019JC-11)Priority Research and Development Foundations of Shaanxi Provincial Government(2018GY-174)Fundamental Research Funds for the Central Universities(No.310201911py010)Open Fund from Henan University of Science and Technology(2020-RSC02)。
文摘Polymer-dispersed liquid crystal(PDLC)films comprising polyvinyl alcohol(PVA)and liquid crystal monomer(LCM)were successfully obtained by the method of solution casting&thermal compressing.LCM was distributed orderly in PVA matrix by hydrogen bond interaction,to form PVA-LCM interpe net rating-layered networks.When the mass fraction of LCM was up to 35 wt%,the corresponding in-plane thermal conductivity coefficient(λ//)of PDLC film was significantly increased to 1.41 W m^(-1)K^(-1),about 10.8 times that of neat PVA(0.13 W m^(-1)K^(-1)).High intrinsicλ//values of PDLC films were mainly attributed to the formed microscopic-ordered structures from ordered stacking of LCM,ordered arrangement of PVA chains,and their hydrogen bond interaction.This work would offer a new way to design and prepare novel intrinsic high thermal conductive polymers.