Yongqiang Guo, Hua Qiu*, Kunpeng Ruan, Yali Zhang and Junwei Gu*. Hierarchically multifunctional polyimide composite films with strongly enhanced thermal conductivity. Nano-Micro Letters, 2021, 10.1007/s40820-021-00767-4. 2020IF=16.419.（1区材料科学Top期刊）

https://doi.org/10.1007/s40820-021-00767-4

Abstract

The development of lightweight and integration for electronics requires flexible films with high thermal conductivity and electromagnetic interference (EMI) shielding to overcome heat accumulation and electromagnetic radiation pollution. Herein, the hierarchical design and assembly strategy was adopted to fabricate hierarchically multifunctional polyimide composite films, with graphene oxide/expanded graphite (GO/EG) as the top thermally conductive and EMI shielding layer, Fe3O4/polyimide (Fe3O4/PI) as the middle EMI shielding enhancement layer and electrospun PI fibers as the substrate layer for mechanical improvement. PI composite films with 61.0 wt% of GO/EG and 23.8 wt% of Fe3O4/PI exhibits high in-plane thermal conductivity coefficient (95.40 W/(m·K)), excellent EMI shielding effectiveness (34.0 dB), good tensile strength (93.6 MPa), and fast electric-heating response (5 s). The test in the central processing unit verifies PI composite films present broad application prospects in electronics fields.

电子产品的轻薄化和高集成化发展亟需具有优异导热和电磁屏蔽性能的柔性薄膜材料来解决其快速热积聚和内在的电磁干扰问题。本文通过分层设计再组装策略制备了上层为氧化石墨烯/膨胀石墨（GO/EG）、中间层为四氧化三铁/聚酰亚胺（Fe3O4/PI）、下层为PI纤维的多层级多功能PI基复合薄膜。当GO/EG和Fe3O4/PI的用量分别为61.0 wt%和23.8 wt%时，HMPM兼具最佳的面内导热系数（95.40 W/(m·K)）、电磁屏蔽效能（34.0 dB），优异的拉伸强度（93.6 MPa）和快速的电热响应性（5 s）。以电脑CPU为实际散热场景验证了PI复合薄膜在轻薄化、小型化的电子设备领域具有广阔应用前景的可能性。

论文创新点

1. 通过分层设计再组装策略制备了多层级多功能聚酰亚胺基柔性复合薄膜。

2. 通过向膨胀石墨中添加少量氧化石墨烯解决了膨胀石墨无法成膜的问题。