Hu Dechao, Ma Wenshi, Zhang Zhilin, Ding Yong, Wu Li
School of Materials Science and Engineering, South China University of Technology, 381 Wushan Road, Guangzhou 510640, PR China.
South China Institute of Collaborative Innovation, Dongguan 523808, PR China.
ACS Appl Mater Interfaces. 2020 Mar 4;12(9):11115-11125. doi: 10.1021/acsami.0c01425. Epub 2020 Feb 21.
Highly thermally conductive, electrically insulating, and flexible nanocellulose composite films are crucially significant for the thermal management of next-generation green electronics. However, the intrinsic hygroscopicity of nanocellulose poses a daunting challenge to the reliability and structural stability of electronic products. To address these issues, herein, a dual bio-inspired design was innovatively introduced to fabricate highly thermally conductive and superhydrophobic nanocellulose-based composite films via vacuum-assisted self-assembly of cellulose nanofibers (CNFs) and hydroxylated boron nitride nanosheets (OH-BNNS) and subsequent hydrophobic modification. Driven by the highly orderly hierarchical architecture and a strong hydrogen bonding interaction, the laminated CNF-based composite films with 50 wt % OH-BNNS show a high in-plane thermal conductivity (15.13 W/mK), which results in a 505% enhancement compared with the pure CNF films. On the other hand, the rough surface combined with a low surface energy modifier endows CNF/OH-BNNS composite films with unique superhydrophobicity (contact angle over 155°) and a simultaneous self-cleaning function. Furthermore, the as-fabricated multifunctional CNF/OH-BNNS composite films were designed as a flexible printed circuit board to simulate the potential applications in the field of cooling electronic devices. The development of CNF/OH-BNNS composite films with synergetic properties of high thermal conductivity and superhydrophobicity may shed light on the functional thermal management materials and offer an innovative insight toward fabricating multifunctional nanocomposites via a dual bio-inspired design.
高导热、电绝缘且柔性的纳米纤维素复合薄膜对于下一代绿色电子产品的热管理至关重要。然而，纳米纤维素固有的吸湿性对电子产品的可靠性和结构稳定性构成了严峻挑战。为了解决这些问题，本文创新性地引入了双重仿生设计，通过纤维素纳米纤维（CNF）和羟基化氮化硼纳米片（OH-BNNS）的真空辅助自组装以及随后的疏水改性，制备出高导热且超疏水的纳米纤维素基复合薄膜。在高度有序的分级结构和强氢键相互作用的驱动下，含有50 wt% OH-BNNS的层状CNF基复合薄膜表现出高的面内热导率（15.13 W/mK），与纯CNF薄膜相比提高了505%。另一方面，粗糙表面与低表面能改性剂相结合，赋予了CNF/OH-BNNS复合薄膜独特的超疏水性（接触角超过155°）和同时具备的自清洁功能。此外，所制备的多功能CNF/OH-BNNS复合薄膜被设计成柔性印刷电路板，以模拟在冷却电子设备领域的潜在应用。具有高导热性和超疏水性协同性能的CNF/OH-BNNS复合薄膜的开发，可能为功能性热管理材料提供启示，并为通过双重仿生设计制备多功能纳米复合材料提供创新思路。
