Yunsong Pang

Gold nanoparticles (Au NPs) provide useful but difficult-to-measure heating in optical tweezers used for colloidal transport, assembly, optofluidics, and bubble-mediated manipulation. Here, we combine 60 nm Au NPs with 5 μm polystyrene (PS) microspheres in a dual-laser Raman optical-tweezers platform. Au NPs serve as heat sources and PS microspheres report the microscale temperature through their Raman spectra. The PS band near 1,000 cm-1 has a calibrated temperature coefficient of -0.0054 cm-1·K-1. For Au stock-dispersion fractions of 0, 0.3, and 1 vol.%, the temperature-power coefficients are 53.5 ± 10.9, 110.4 ± 23.8, and 170.3 ± 18.2 K·W-1, respectively. At 1 vol.% Au suspension, extrapolation of the pre-bubble temperature-power relation to 0.341 W gives a PS-reported temperature of approximately 351 K, below the normal boiling point of water. Electromagnetic simulations show that normalized per-particle absorption increases from 1.00 for an isolated Au nanoparticle to 15.35 for a seven-particle cluster, supporting aggregation-induced nanoscale heating as a mechanism for bubble formation. The PS reporter thus gives the microscale thermal response, and the nanoscale hotspots associated with bubble formation are inferred, not measured directly.

The pursuit of efficient thermal management for AI electronics devices requires TIMs capable of simultaneously lowering bulk and contact thermal resistance. Herein, we report a phase‐change TIM (PC‐TIM) designed on this principle, synthesized by grafting octadecane onto poly(methylhydrosiloxane) and compounding it with polydimethylsiloxane and aluminum fillers. Owing to structural polar compatibility among the polymer chains, the material achieves exceptional stability with a leakage ratio below 0.3 wt.%, alongside a low thermal resistance of 0.03°C·cm ² ·W ^−1— performance that is competitive with leading polymer‐based and commercial TIMs. The outstanding performance is attributed to a multiscale optimization strategy: macroscale reorganization of polymer chains and the filler network reduce bond line thickness; microscale enhancement in compliance ensures conformal contact; and atomic‐scale improvements in wettability and phonon spectrum matching jointly boost cross‐interface heat transfer. The effectiveness of PC‐TIM has been validated in multiple devices, including LEDs, optical modules, and MOSFETs, where it exhibits outstanding heat dissipation performance, superior to the referenced commercial products. Notably, in AI‐oriented GPU tests, the PC‐TIM reduced the operating temperature by an additional 5°C compared to the original TIM while maintaining excellent stability.

In recent years, adhesive thermal interface materials have attracted much attention because of their reliable adhesion properties on most substrates, preventing moisture, vibration impact, or chemical corrosion damage to components and equipment, as well as solving the heat dissipation problem. However, thermal interface materials have a huge contradiction between strong adhesion and high thermal conductivity. Here, we report a polymer-based thermal interface material consisting of polydimethylsiloxane/spherical aluminum fillers, which possesses both adhesion properties (adhesion strength of 3.59 MPa and adhesion toughness of 1673 J m^-2 and enhanced thermal conductivity of 3.90 W m^-1 K^-1). These excellent properties are attributed to the modified chain structure by introducing acrylate accelerators into the polydimethylsiloxane network, thereby striking a balance between interfacial toughness and intrinsic dissipation. The addition of thermally conductive aluminum fillers not only increases the thermal conductivity but also improves the bulk energy dissipation of the thermal interface material. This work provides a novel strategy for designing a novel thermal interface material, leading to new ideas in long-term applications in high-power electronics.

The multifunctional composite elastomers serve as thermal interface materials for heat dissipation in electronic devices when their thermal transport performance is enhanced. The common method for enhancement, continuously raising the thermal conductive filler loading only can improve thermal conductivity of composite elastomers but reduces compliance, resulting in elevated contact thermal resistance with solid surfaces, compromising thermal transport. To address this, we propose grafting short dangling chains onto the composite elastomer matrix to further promote compliance under a certain filler loading. Characterization results demonstrate that the grafted chains effectively reduce relaxation time, enabling faster deformation for the material under pressure. This approach enhances interfacial compatibility, widening the thermal transport path at contact interfaces to contact thermal resistance by 94% (from 17.8 to 1.07 mm²W/K), significantly improving overall thermal transport. Additionally, we discussed the feasibility of employing composite elastomers as thermal interface materials for efficient chip heat dissipation.Highlight: The grafted dangling chains can promote the composite elastomers softness. The softness promotion can help reduce thermal contact resistance. A series of theories are employed to learn the mechanisms of the promotion. The resulting composite elastomers can be used as thermal interface materials.

Adhesion ability and interfacial thermal transfer capacity at soft/hard interfaces are of critical importance to a wide variety of applications, ranging from electronic packaging and soft electronics to batteries. However, these two properties are difficult to obtain simultaneously due to their conflicting nature at soft/hard interfaces. Herein, we report a polyurethane/silicon interface with both high adhesion energy (13535 J m^-2) and low thermal interfacial resistance (0.89 × 10^-6 m² K W^-1) by regulating hydrogen interactions at the interface. This is achieved by introducing a soybean-oil-based epoxy cross-linker, which can destroy the hydrogen bonds in polyurethane networks and meanwhile can promote the formation of hydrogen bonds at the polyurethane/silicon interface. This study provides a comprehensive understanding of enhancing adhesion energy and reducing interfacial thermal resistance at soft/hard interfaces, which offers a promising perspective to tailor interfacial properties in various material systems.

The pursuit of enhancing the heat transfer performance of composite elastomers as the thermal interface materials (TIMs) is a compelling and timely endeavor, given the formidable challenges posed by interfacial thermal transport in the domains of energy science, electronic technology, etc. Despite the efficacy of phase change materials (PCMs) in enhancing composite elastomers’ interfacial compatibility, thereby reducing contact thermal resistance for heat transfer improvement, their leakage post‐transition has impeded the widespread adoption of this approach. Herein, a strategy is proposed for developing a solid‐solid phase change composite elastomer by grafting alkene chains onto the crosslink network to eliminate the possibility of leakage. A series characterization suggest that the resulting material possesses a self‐adjusting interfacial compatibility feature to help reduce contact thermal resistance for heat transfer facilitating. The investigations on adhesion strength and surface energy reveal that the presence of amorphous grafted alkane chains at the interface facilitates easier absorption onto the contacting solid surface, enhancing intermolecular interactions at the interface to promote across‐boundary heat transfer. By integrating these findings with the thermal performance evaluation of composite elastomers using a real test vehicle, valuable insights are gained for the design of composite elastomers, establishing their suitability as TIMs in relevant fields.