摘要：
Flexible electronics face increasing challenges in thermal management due to their high heat flux and compact form factors. Traditional metal-based heat sinks often fail to meet the foldable requirements of these flexible devices, while polymer-based microfluidic heat sinks are constrained by the inherently low thermal conductivity (TC) of polymer substrates. This study presents a novel flexible thermally conductive composite, enhanced with a 2D metal framework, designed for application in microfluidic heat sinks and flexible thermal management applications. The composite, consisting of copper screen, graphene, and polydimethylsiloxane (PDMS), was systematically characterized for its flexibility, conformability, TC, mechanical properties, and thermal stability. Results demonstrate a significant enhancement in TC, with in-plane TC reaching 4.3 W·m−1·K−1, a 2609.4% increase compared to pure PDMS. The composite also exhibited superior mechanical performance (17.0 MPa, a 1242.9% increase) and favorable electromagnetic interference (EMI) shielding effectiveness (34.0 dB, a 2065.6% enhancement). Notably, the material maintained exceptional flexibility and durability, preserving its thermal performance even after one million bending cycles. Furthermore, microfluidic heat sinks fabricated with this composite showed notable thermal performance, with uniform temperature distributions (SDT < 8 °C) and minimal temperature variations (<5 °C) across varying flow rates and bending conditions. The device also achieved high energy efficiency, with a coefficient of performance (COP) up to 31,000, and favorable thermal dynamic stability, with only a 4% temperature fluctuation under continuous bending. This work offers a promising solution for advanced thermal management in next-generation flexible electronics, wearable devices, and integrated thermal management applications.
