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

Interfaces play an important role in the heat and stress transfer within applications such as electronic cooling. The coexistence of apparently contradictory properties between heat dissipation and adhesion at interfaces poses a constant challenge for existing interface materials. Herein, a thermal interface material is reported, consisting of epoxy‐functionalized polydimethylsiloxane and aluminum fillers with excellent interfacial heat/force transfer ability. This material optimizes the combination of thermal conductivity of 3.46 W m−1 K−1 and adhesion energy of 1.17 kJ m−2. Using two viscoelastic models, the excellent interfacial force transfer ability is attributed to a hierarchical energy dissipation via the introduction of borate ester bonds and the aluminum filler networks. A simple kinetic bond model demonstrates that the borate ester bonds increase molecular chain segment mobility, allowing full extension at debonding interface for stress dispersion and efficient energy dissipation. The aluminum filler networks not only facilitate thermal transfer, but also dissipate the mechanical energy during filler network destruction due to the bond breakage between fillers. The excellent heat dispassion and mechanical stability are further demonstrated when this thermal interface material is used in flexible light emitting diodes and high‐power chips. This work provides a new strategy for balancing interfacial heat and force transfer. [ABSTRACT FROM AUTHOR]

Thermal interface materials (TIMs) play a pivotal role in the transfer of heat from high‐temperature sources, such as CPUs, to heat sinks in power electronics. The effectiveness of grease‐type TIMs is determined by their effective thermal impedance (REFF), which hinges on optimizing both the specific bulk (RB) and contact (RC) thermal resistances. Achieving concurrent optimization of these resistances poses a significant challenge, especially in high filler loading TIMs, typically above 76 vol%. This research leverages interface engineering through Self‐Assembled Monolayers (SAMs) to address this challenge. A substantial decrease in REFF is realized to 0.169 K cm2 W−1, a tenfold enhancement compared to non‐SAM treated TIMs, which exhibit REFF values of 2.265 K cm2 W−1. This leap in performance is primarily ascribed to the reduced surface energy of SAM treated Al2O3, leading to lower particle‐to‐particle Van der Waals forces, thereby improving particle dispersion and strengthening interfacial bonds. Furthermore, longer carbon chains in SAMs result in increased RB, yet a decrease in RC, due to the chains' capacity for enhanced energy absorption and molecular entanglement. The investigation underscores the significance of shorter‐chain SAMs in fine‐tuning thermal resistance, highlighting the crucial role of molecular architecture in the design of advanced TIMs. [ABSTRACT FROM AUTHOR]

The relationship between interfacial structure and thermal conductivity in epoxy resin/Al2O3 composite is important but is still elusive. Here, we illuminate this issue by investigating the role of four silane coupling agents in thermal conductivity for epoxy resin/Al2O3 composites. The results show that 3‐glycidoxypropyltrimethoxysilane (KH560) is the best silane coupling agent to modify Al2O3, resulting in the lowest viscosity and the highest thermal conductivity of the epoxy resin/Al2O3‐KH560 composite compared with alternative systems. This is attributed to the strong interfacial interaction between Al2O3‐KH560 and epoxy resin, as confirmed by the Fowkes model and broadband dielectric spectroscopy. The interfacial thermal resistance between the epoxy resin and Al2O3 is also quantitatively measured via a photothermal radiometry technique. The epoxy resin/Al2O3‐KH560 also has the lowest interfacial thermal resistance (1.50 ± 0.02 × 10−6 m2 K W−1), compared with the other three systems. This study advances the understanding of the relationship between interfacial structure and thermal conductivity in polymer composites. Highlights: The relationship between interfacial structure and thermal conductivity in epoxy resin/Al2O3 composite is understood.The interfacial structure is characterized by broadband dielectric spectroscopy.The interfacial thermal resistance is quantitatively measured via a photothermal radiometry technique. [ABSTRACT FROM AUTHOR]

Elastomers are widely used for their large‐strain reversible stretchability, but their low thermal conductivity limits their applications in thermal management. Increasing the thermal conductivity of elastomers usually involves adding fillers, which deteriorate their stretchability and other desirable properties. Here, a supramolecular structure design strategy is proposed to enhance the thermal conductivity of amorphous elastomers without compromising their stretchability and self‐healing abilities. Supramolecular poly(thioctic acid‐N,N′‐methylenebis acrylamide) elastomers are designed with ordered hydrogen bonding interactions that improve the heat transfer efficiency and maintain excellent stretchability. The resulting elastomers exhibit a thermal conductivity of 0.72 W m−1 K−1, a remarkable stretchability of 427%, a low elastic modulus of 475 kPa, and self‐healing and reprocessing capabilities. This strategy offers a promising alternative for developing thermally conductive elastomers that do not rely on traditional fillers. [ABSTRACT FROM AUTHOR]