Bilayered Distribution of Ag and Fe₃O₄ in Electrospun TPU Films for Low-Reflection Electromagnetic Interference Shielding and Multiple Thermal Management Functionalities

Low-reflection electromagnetic interference (EMI) shielding composites are crucial to next-generation electronic equipment. Moreover, it is highly desirable to integrate thermal management performance into the composites to broaden their applications. Herein, a bilayered EMI shielding composite film with thermal management performances was fabricated successfully via electrospinning, in situ growth, and hot-pressing approaches. Fe₃O₄ particles are distributed in the upper layer for EM wave absorption and photothermal conversion, while Ag particles are distributed in the lower layer for EMI shielding, thermal conduction, and electrothermal conversion. The resultant film achieved a remarkable EMI shielding effectiveness of 98.2 dB with an average reflection coefficient value as low as 0.64. Subsequently, the composite film showed an optimum in-plane thermal conductivity of 6.49 W/(m·K), due to the three-dimensional (3D) interconnected network of Ag particles. In addition, the upper layer of the composite film exhibited admirable photothermal conversion performance, reaching a saturated temperature of 91.3 °C (1 sun). Meanwhile, the lower layer of the composite film showed favorable electrothermal conversion performance, contributing to a high saturated temperature of 92.6 °C (6 V). This work would propose one novel strategy for developing low-reflection EMI shielding composite films integrated with multiple thermal management functionalities in microelectronic systems.