Magneto-responsive thermal switch for remote-controlled locomotion and heat transfer based on magnetic nanofluid

Heat transfer and thermal management have garnered widespread attention due to their industrial applications, particularly for thermal and electronics devices. Therefore, new thermal management solutions are urgently required to maintain optimum temperature and efficiency of the systems. Herein, Fe3O4 magnetic nanofluid was prepared to establish the quick heat conduction channel between heat source and heat sink relying on the high thermal conductivity. And a magneto-responsive remote-controlled heat transfer method was presented by controlling the external physical field and material property. The appearance and disappearance of magnetic "needle-like protuberance" could be tuned by external magnetism ON or OFF. The magnetic responsiveness, adjustability and recyclability of heat transfer have been demonstrated experimentally. The Nusselt number at 30 mT has an enhancement of 112.4% compared to that without magnetic field. And the overheating protection experiments in the heat sink showed that it can effectively reduce the working temperature of electronic components, and the steady temperature decreased by 22.6% using Fe3O4 magnetic nanofluid when applying a magnetic field. This research exhibited a novel approach to achieve excellent heat exchange characteristics by tuning the magnetic field intensities for the utilization of thermal management.