Kunpeng Ruan, Mukun Li, Yuheng Pang, Mukun He, Hua Guo*, Xuetao Shi and Junwei Gu*. Molecular Brush-Grafted Liquid Crystalline Hetero-Structured Fillers for Boosting Thermal Conductivity of Polyimide Composite Films. Advanced Functional Materials, 2025, 10.1002/adfm.202506563.2023IF=18.5.（1區材料科學Top期刊）
https://advanced.onlinelibrary.wiley.com/doi/10.1002/adfm.202506563
Abstract
Hetero-structured thermally conductive fillers, benefiting from the low interfacial thermal resistance and fillers’ synergistic effect, have been proven to be the ideal choice for improving the thermal conductivities of polymer composites. However, hetero-structured fillers are usually disorderly distributed in the polymer matrix, hindering the further improvement of the efficiency of constructing thermal conduction pathways in polymer composites. This work proposes the new strategy to graft polymethyl methacrylate molecular brushes on the surfaces of fluorinated graphene@carbon nanotube (FG@CNT) hetero-structured thermally conductive fillers by atom transfer radical polymerization. FG@CNT is orderly arranged and present the liquid crystalline state (LC-(FG@CNT), which are then introduced into the liquid crystalline polyimide (LC-PI) matrix with high intrinsic thermally conductivity to fabricate LC-(FG@CNT)/LC-PI thermally conductive composite films. The in-plane and through-plane thermal conductivities (λ∥, λ⊥) of 15 wt% LC-(FG@CNT)/LC-PI films reach 5.66 and 0.76 W·m-1·K-1, respectively, which are 168.2% and 137.5% higher than those of the LC-PI films (λ∥=2.11 W·m-1·K-1, λ⊥=0.32 W·m-1·K-1), also significantly higher than those of 15 wt% FG@CNT/LC-PI composite films (λ∥=4.72 W·m-1·K-1, λ⊥=0.74 W·m-1·K-1). Demonstrated by heat dissipation testing and finite element simulation, the LC-(FG@CNT)/LC-PI composite films show excellent thermal management capabilities and great application potential in the new generation of flexible electronic devices.
異質結構導熱填料受益于低界面熱障和填料協同效應，已被證明是提升高分子復合材料導熱性能的理想選擇，但其往往在高分子基體內無序分布，影響高分子復合材料內導熱通路構筑效率的進一步提升。本文提出通過原子轉移自由基聚合在氟化石墨烯@碳納米管（GeF@CNT）異質結構導熱填料表面接枝聚甲基丙烯酸甲酯分子刷的新策略，使GeF@CNT有序排列并呈液晶態（LC-(GeF@CNT)），并將其引入本征高導熱液晶聚酰亞胺（LC-PI）基體中制備LC-(GeF@CNT)/LC-PI導熱復合膜。當LC-(GeF@CNT)的質量分數為15 wt%時，LC-(GeF@CNT)/LC-PI導熱復合膜室溫下的面內導熱系數（λ∥）和面間導熱系數（λ⊥）分別達到5.66 W·m-1·K-1和0.76 W·m-1·K-1，較本征導熱LC-PI膜的λ∥（2.11 W·m-1·K-1）和λ⊥（0.32 W·m-1·K-1）提升了168.2%和137.5%，也明顯高于相同GeF@CNT用量下GeF@CNT/LC-PI導熱復合膜（λ∥=4.72 W·m-1·K-1，λ⊥=0.74 W·m-1·K-1）。經實際散熱測試和有限元模擬，LC-(GeF@CNT)/LC-PI導熱復合膜展現出優異的熱管理能力，在新一代柔性電子設備中具備強大的應用潛力。
論文亮點
1. 以氨基化改性氟化石墨烯（f-GeF）和羧基化改性CNT（f-CNT）為基本組分，通過化學鍵合法制備了具有“線-面”異質結構的GeF@CNT導熱填料。
2. 通過原子轉移自由基聚合在GeF@CNT異質結構導熱填料表面接枝聚甲基丙烯酸甲酯分子刷，使GeF@CNT有序排列并呈液晶態（LC-(GeF@CNT)）。
3. 當LC-(GeF@CNT)的質量分數為15 wt%時，LC-(GeF@CNT)/LC-PI導熱復合膜室溫下的λ∥和λ⊥分別達到5.66 W·m-1·K-1和0.76 W·m-1·K-1，較本征導熱LC-PI膜的λ∥和λ⊥提升了168.2%和137.5%，也明顯高于相同GeF@CNT用量下GeF@CNT/LC-PI導熱復合膜。
第一作者：阮坤鵬
郵件地址：ruankunpeng@nwpu.edu.cn
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