基于银微米纤维导电网络的超高电磁屏蔽且耐极端环境聚酰亚胺薄膜

Extreme environment-bearable polyimide film with a three-dimensional Ag microfiber conductive network for ultrahigh electromagnetic interference shielding

聚合物基电磁屏蔽材料可以保证电子设备的正常运行以及保护人体免受电磁辐射的伤害,因而在电子通信领域得到了广泛的发展.然而,制备在恶劣环境中(例如:太空中的极高温和极低温环境)仍具有超高电磁屏蔽效率(EMI SE)、低厚度、高耐用性和柔性的电磁屏蔽复合材料仍然是一个挑战.在本研究中,我们通过气流纺丝和压缩成型相结合的方法,构建了一种银微米纤维海绵(AgMS)/聚酰亚胺(PI)电磁屏蔽膜.在AgMS/PI薄膜厚度仅为20μm时,由28 vol%AgMS构成的三维导电网络使其具有极高的导电性(4.5×10^(6)S m^(-1))和高达90.6 d B的电磁屏蔽效率.该薄膜在-196和250℃条件下持续120 h,均能保持良好的电磁屏蔽性能,且电磁屏蔽效率均保持在85.1 d B以上.此外,AgMS/PI薄膜还表现出出色的热管理性能,比如在极低的供电电压(1.1 V)下实现200.2℃的高饱和温度,快速的响应时间(3.1 s),优秀的循环加热稳定性和出色的可靠性.这些优异的性能表明AgMS/PI薄膜在恶劣环境下的电子通讯领域和人工智能领域具有巨大的应用潜力.

To ensure the normal operation of electronic equipment and provide protection from electromagnetic radiation,polymer-based electromagnetic interference(EMI)shielding materials are widely developed in the electronic communication field.However,it remains a challenge to prepare EMI shielding composites with ultrahigh EMI shielding efficiency(EMI SE),low thickness,high durability,and flexibility in harsh environments,such as extremely high or low temperatures in aerospace.In this study,we used blow spinning and compression molding to construct a highly efficient EMI shielding polyimide(PI)film containing a Ag microfiber sponge(AgMS).The three-dimensional(3D)conductive network constructed by 28-vol%AgMS endows the Ag MS/PI film with very high electrical conductivity of 4.5×10^(6)S m^(-1)and an EMI SE of up to 90.6 d B,at only 20-μm thickness.Even after working at-196 or 250℃for 120 h,the excellent EMI shielding performance is maintained,with EMI SE retention higher than 85.1 d B.Furthermore,AgMS/PI film exhibits outstanding thermal management performance,achieving a high saturation temperature of 200.2℃at very low supplied voltage(1.1 V),revealing a quick response time(3.1 s),excellent cyclic heating stability,and outstanding reliability.These outstanding properties indicate the great potential of AgMS/PI films in the electronic communication field under harsh environments and artificial intelligence.