Hydrogen Bonds Significantly Enhance Out-of-Plane Thermal and Electrical Transport in 2D Graphamid: Implications for Energy Conversion and Storage

Ma, Hao; Li, Chen; Tian, Zhiting

doi:10.1021/acsanm.0c02261

Cited by 6 publications

(4 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, simulations have shown that enhancing intermolecular interactions with hydrogen bonds could significantly improve thermal conductivity. 65,66 At high contrast ratios, thermal conductivity increases linearly with NP size, which is a direct result of depleting interfaces (Figure 4g). We begin to observe saturated enhancements at k f /k m = 60.5 (Fe 3 O 4 ), albeit maintaining a substantial increase in thermal conductivity with size, once again highlighting that thermal percolation is not exclusive to highly conductive fillers such as graphene (k f /k m = 10 5 ).…”

Section: ■ Results and Discussionmentioning

confidence: 98%

“…This result has significant implications as van der Waals bonded matrix–filler interfaces, which represent the most common type of polymer composite, fall under this regime. , Hence, despite the formation of networks, thermal percolation is unlikely to occur when the filler is weakly bonded to the organic phase. However, simulations have shown that enhancing intermolecular interactions with hydrogen bonds could significantly improve thermal conductivity. , …”

Section: Results and Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Thermal Percolation in Well-Defined Nanocomposite Thin Films

Chang

Dai

et al. 2022

ACS Appl. Mater. Interfaces

Self Cite

View full text Add to dashboard Cite

Thermal percolation in polymer nanocomposites the rapid increase in thermal transport due to the formation of networks among fillersis the subject of great interest in thermal management ranging from general utility in multifunctional nanocomposites to high-conductivity applications such as thermal interface materials. However, It remains a challenging subject encompassing both experimental and modeling hurdles. Successful reports of thermal percolation are exclusively found in high-aspectratio, conductive fillers such as graphene, albeit at filler loadings significantly higher than the electrical percolation threshold. This anomaly was attributed to the lower filler−matrix thermal conductivity contrast ratio k f /k m ∼10 4 compared to electrical conductivity ∼10 12 −10 16 . In a randomly dispersed composite, the effect of a low contrast ratio is further accentuated by uncertainties in the morphology of the percolating network and presence of other phases such as disconnected aggregates and colloidal dispersions. Thus, the general properties of percolating networks are convoluted as they lack a defined structure. In contrast, a prototypical system with controllable nanofiller placement enables the elucidation of structure−property relations such as filler size, loading, and assembly. Using self-assembled nanocomposites with a controlled 1,2,3-dimension nanoparticle (NP) arrangement, we demonstrate that thermal percolation can be achieved in spite of using spherical, nonconductive fillers (k f /k m ∼60) at a low volume fraction (9 vol %). We observe that the effects of volume fraction, interfacial thermal resistance, and filler conductivity on thermal conductivity depart from effective medium approximations. Most notably, contrast ratio plays a minor role in thermal percolation above k f /k m ∼60a common range for semiconducting nanoparticles/polymer ratios. Our findings bring new perspectives and insights to thermal percolation in nanocomposites, where the limits in contrast ratio, interfacial thermal conductance, and filler size are established.

show abstract

Section: ■ Results and Discussionmentioning

confidence: 98%

Section: Results and Discussionmentioning

confidence: 99%

Thermal Percolation in Well-Defined Nanocomposite Thin Films

Chang

Dai

et al. 2022

ACS Appl. Mater. Interfaces

Self Cite

View full text Add to dashboard Cite

show abstract

“…The system was relaxed in isothermal–isobaric (NPT), canonical (NVT), and microcanonical (NVE) ensembles subsequently for 100, 50, and 50 ps, respectively, and then heat flux data was collected in an NVE ensemble for another 1 ns. The k was determined with the Green–Kubo formula, which relates the ensemble average of the autocorrelation of the heat flux to k . − …”

Section: Methodsmentioning

confidence: 99%

Significantly Enhanced Thermal Conductivity of hBN/PTFE Composites: A Comprehensive Study of Filler Size and Dispersion

Alexis,

Lee,

Alvarez

et al. 2024

ACS Appl. Mater. Interfaces

Self Cite

View full text Add to dashboard Cite

High-temperature polymers are attractive for applications in extreme temperatures, where they maintain their mechanical flexibility and electrical insulating properties. However, their heat dissipation capability is limited due to their intrinsically low thermal conductivities. Hexagonal boron nitride (hBN) is a chemically inert, thermally stable, and electrically insulative compound with a high thermal conductivity, making it an ideal candidate as a filler within a high-temperature polymer matrix to increase the thermal conductivity. This study evaluates the effect of filler size and dispersion on thermal conductivity by producing homogeneous composite samples using a combination of solvent mixing and resonant acoustic mixing (RAM). We carefully characterized our samples, including the spread of the size distribution, and observed that the smaller sized hBN centered around 5 μm was able to integrate more seamlessly into the polytetrafluoroethylene (PTFE) matrix with particle size in the 15 μm range and hence outperformed 30 μm, in contrast to the conventional wisdom, which asserts that larger fillers universally perform better than smaller ones. Our thermal conductivity of hBN/PTFE composites at 30 wt % is 2× higher than the literature values. Notably, we reached the record-high value of 3.5 W/m K at 40 wt % with an onset of percolation at 20 wt %, attributed to optimized hBN dispersion that facilitates the formation of thermal percolation. Our findings provide general guidelines to enhance the thermal conductivity of polymer composites for thermal management, ranging from power transmission to microelectronics cooling.

show abstract

“…This is mainly because the force fields lack key parameters (such as the π−π interactions) that are necessary to keep the columnar pores and the stacked layers intact. In addition, although PCFF can handle nonbonded interactions such as π−π interactions and hydrogen bonds, 38 it cannot describe some complicated covalent bonds or interactions between multiple atoms. Therefore, lacking some key parameters required to correctly model all interactions in COFs, these potentials are not fully equipped to study the fundamental thermal transport processes for a wide array of COF structures.…”

Section: Simulations As Discussed Above MD Simulations Have Already P...mentioning

confidence: 99%

Thermal Conductivity of Covalent-Organic Frameworks

Kwon

Giri

et al. 2023

ACS Nano

Self Cite

View full text Add to dashboard Cite

Covalent-organic frameworks (COFs) are a highly promising class of materials that can provide an excellent platform for thermal management applications. In this Perspective, we first review previous works on the thermal conductivities of COFs. Then we share our insights on achieving high, low, and switchable thermal conductivities of future COFs. To obtain the desired thermal conductivity, a comprehensive understanding of their thermal transport mechanisms is necessary but lacking. We discuss current limitations in atomistic simulations, synthesis, and thermal conductivity measurements of COFs and share potential pathways to overcoming these challenges. We hope to stimulate collective, interdisciplinary efforts to study the thermal conductivity of COFs and enable their wide range of thermal applications.

show abstract

Hydrogen Bonds Significantly Enhance Out-of-Plane Thermal and Electrical Transport in 2D Graphamid: Implications for Energy Conversion and Storage

Cited by 6 publications

References 50 publications

Thermal Percolation in Well-Defined Nanocomposite Thin Films

Thermal Percolation in Well-Defined Nanocomposite Thin Films

Significantly Enhanced Thermal Conductivity of hBN/PTFE Composites: A Comprehensive Study of Filler Size and Dispersion

Thermal Conductivity of Covalent-Organic Frameworks

Contact Info

Product

Resources

About