The ability to modulate heat transfer with widely tunable and high thermal conductance is desirable for various applications in energy conversion, thermal management, and thermal logics. Current thermal switches based on controlling heat conduction via forming and breaking mechanical contacts are limited by the narrow range of conductance modulation and the low conductance value when the switch is at the ON state, and/or suffer from reliability issues due to the use of liquid metal or high contact pressure. Here, we demonstrated widely tunable liquid-vapor phase change heat transfer with high thermal conductance. While traditional phase change heat transfer phenomena, such as boiling and evaporation, are often not tunable, we utilized a new “thin film boiling” mechanism recently discovered by us. We implemented the thin film boiling of a low surface tension fluid, ethanol, on nanoporous membranes, which showed a wide range of boiling curves with negative differential thermal conductance (NDTC), that is, decreasing superheat with increasing heat flux. Importantly, this NDTC is fully reversible and can be actively tuned by changing the liquid pressure. This unique feature enables us to actively and reversibly regulate the thermal conductance over a wide range of working conditions. The demonstrated ON/OFF conductance ratio was over 6000, and during the ON states, the conductance could be modulated over 100 times. Additionally, the maximum ON state conductance is close to 20 W/cm² K, which is an order of magnitude higher than that of the current solid/solid contact thermal switches. This work paves the way for constructing active thermal switches and regulators to dynamically control heat transfer for a variety of applications.

在能量转换，热管理和热逻辑的各种应用中，希望能够以广泛的可调性和高热导率来调节热传递。基于通过形成和断开机械触点来控制热传导的当前热敏开关受到电导调制的窄范围和当开关处于导通状态时的低电导值的限制，和/或由于使用液体而遭受可靠性问题金属或高接触压力。在这里，我们展示了具有高导热率的可广泛调节的液体-蒸汽相变传热。尽管传统的相变传热现象（例如沸腾和蒸发）通常是不可调节的，但我们利用了我们最近发现的一种新的“薄膜沸腾”机理。我们在纳米多孔膜上实施了一种低表面张力流体乙醇的薄膜沸腾工艺，该工艺在负电导率差（NDTC）的情况下显示了宽泛的沸腾曲线，即随着热通量的增加而降低了过热度。重要的是，该NDTC是完全可逆的，并且可以通过更改液体压力来积极地进行调整。这种独特的功能使我们能够在广泛的工作条件下主动且可逆地调节热导率。演示的开/关电导率超过6000，在开状态下，电导可以调制100倍以上。此外，最大导通状态电导接近20 W / cm 随着热通量的增加而降低过热度。重要的是，该NDTC是完全可逆的，并且可以通过更改液体压力来积极地进行调整。这种独特的功能使我们能够在广泛的工作条件下主动且可逆地调节热导率。演示的开/关电导率超过6000，在开状态下，电导可以调制100倍以上。此外，最大导通状态电导接近20 W / cm 随着热通量的增加而减少过热。重要的是，该NDTC是完全可逆的，并且可以通过更改液体压力来积极地进行调整。这种独特的功能使我们能够在广泛的工作条件下主动且可逆地调节热导率。演示的开/关电导率超过6000，在开状态下，电导可以调制100倍以上。此外，最大导通状态电导接近20 W / cm 电导可以调制100倍以上。此外，最大导通状态电导接近20 W / cm 电导可以调制100倍以上。此外，最大导通状态电导接近20 W / cm² K，比当前的固态/固态接触式热敏开关高一个数量级。这项工作为构造有源热控开关和调节器以动态控制各种应用的热传递铺平了道路。