The advancement of electronic devices is trending toward miniaturization, integration, and intelligence, necessitating the adoption of efficient thermal management techniques to boost system performance and reliability. This is particularly critical in burgeoning fields such as soft robotics, electronic skin, wearable devices, and flexible displays, where there is a demand for thermal management materials that not only transfer heat effectively but are also soft and stretchable, thus maintaining mechanical compliance. However, most soft materials exhibit low thermal conductivity due to their amorphous structure and associated phonon scattering events. Polymers, for instance, typically display thermal conductivities ranging from 0.1 to 0.5 W m-1 K-1. Extensive efforts have been directed toward engineering polymer composites with highly thermally conductive fillers such as graphene nanosheets (GNs), carbon nanotubes (CNTs), boron nitride nanosheets (BNNSs), boron nitride nanotubes (BNNTs), and MXene nanosheets. Although these composites demonstrate enhanced thermal conductivity, their high filler loadings often lead to the creation of materials that are mechanically stiff and lack the necessary stretchability. The challenge of designing soft composites that combine high thermal conductivity with mechanical compliance remains significant.
Recently, Professor Yagang Yao’s Group at Nanjing University has proposed a noncovalent assembly strategy for developing novel soft composites, designated as PULG, facilitated by polyphenol-mediated binary fillers of LM and GN, specifically LM-TA-GN, embedded in a polyurethane (PU) matrix. Natural polyphenols, such as tannic acid (TA), possess numerous hydrophobic aromatic rings and hydrophilic phenolic hydroxyl groups, fostering multiple interfacial supramolecular interactions within the composite. These interactions between LM-TA-GN particles and PU chains are crucial, allowing the composite to achieve exceptional thermal conductivity and mechanical compliance. Moreover, the composite displays robust broadband light absorption and outstanding photothermal conversion efficiency, effective under both normal sunlight and 808 nm near-infrared laser irradiation. The findings overcome the traditional trade-off between high thermal conductivity and mechanical compliance in a single material. This design strategy will pave the way for advanced thermal management materials that require functional integration.
Figure 1. Chemical structure and design concept of PULG composites. a) Schematic illustration of the nanostructure of PULG composites. b) Schematic illustration of the interfacial supramolecular interactions of PULG composites. c) Schematic illustration of the diverse functionalities of PULG composites for potential thermal management applications.
Figure 2. Characterization of PULG composites.
Figure 3. Mechanical performance of PULG composites.
Figure 4. Thermal conductivity of PULG composites.
Figure 5. Photothermal performance of PULG composites.
The related research work, titled “Noncovalent Soft Composites with Superior Thermal Conductivity and Photothermal Efficiency for Advanced Thermal Management,” was published in Nano Letters. Xuhua He, a 2021 Ph.D. candidate at the College of Engineering and Applied Sciences at Nanjing University, served as the first author of the paper, with Professor Yagang Yao as the corresponding author. This work was supported by the National Key R&D Program of China (2024YFE0109200), the Fundamental Research Funds for the Central Universities (No. 2024300440), and Guangdong Basic and Applied Basic Research Foundation (2025A1515011098). The experimental work for this study received significant support from the research groups of Professors Zhaosheng Li, Hui Wei, and Xuebin Wang at the College of Engineering and Applied Sciences, Nanjing University. The work also received strong support and assistance from the National Laboratory of Solid State Microstructures, the College of Engineering and Applied Sciences, the Jiangsu Key Laboratory of Artificial Functional Materials, the Collaborative Innovation Center of Advanced Microstructures at Nanjing University, and the Shenzhen Research Institute of Nanjing University.
Article link：https://doi.org/10.1021/acs.nanolett.5c01391
