A review of microfluidic technologies for thermal management in flexible electronics

Flexible electronics with the features of soft, ultrathin, and shape adaptable properties, are believed as next-generation devices for physiological monitoring, digital diagnostics, and human-computer interaction. With the development of devices towards miniaturization and integration, thermal management has emerged as an essential challenge, which not only influences device performance and long-term stability but also affects user comfort. Various thermal management strategies, including passive and active approaches, have been employed to regulate the operating temperature. Nevertheless, it is still challenging to develop thermal regulation systems with a large temperature regulation range, good temperature uniformity, and high mechanical flexibility. Recently, the microfluidics-based thermal regulation method has emerged as a promising method that integrates active and passive thermoregulation methods. This review explores the thermal management mechanisms enabled by microfluidic devices, emphasizing an integrated strategy that combines material selection, structural geometry, and system optimization to enhance thermal performance. We analyze heat transfer principles in microchannels and highlight applications in device-level thermal management, personal thermal regulation, and thermal regulation interface for human-machine interaction and healthcare, addressing their specific demands. Finally, we outline the challenges and future perspectives for advancing microfluidics-based thermal management systems, focusing on capability, integration, and applications.