Generating customised temperature gradients in miniaturised flow-free liquid chambers is challenging due to the dominance of diffusion. Inducing internal flows in the form of vortices is an effective strategy for overcoming the limitations of diffusion in such environments. Vortices can be produced by applying pressure, temperature and electric potential gradients via miniaturised actuators. However, the difficulties associated with the fabrication, integration, maintenance and operation of such actuators hinder their utility. Here, we utilise liquid metal enabled pumps to induce vortices inside a miniaturised liquid chamber. The configuration and rotational velocity of these vortices can be controlled by tuning the polarity and frequency of the energising electrical signal. This allows creation of customised spatial temperature gradients inside the chamber. The absence of conventional moving elements in the pumps facilitates the rapid reconfiguration of vortices. This enables quick transition from one temperature profile to another, and creates customised spatiotemporal temperature gradients. This allows temperature oscillation from 35 to 62 °C at the hot spot, and from 25 to 27 °C at the centre of the vortex within 15 seconds. Our liquid metal enabled vortex generator can be fabricated, integrated and operated easily, and offers opportunities for studying thermo-responsive materials and biological samples.

中文翻译：

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由启用液态金属的涡流发生器创建的定制时空温度梯度

由于扩散占主导地位，因此在小型无流动液体腔室中生成定制的温度梯度具有挑战性。以涡流形式产生内部流动是克服此类环境中扩散限制的有效策略。涡流可以通过施加压力，温度和电位梯度来产生经由小型化的执行器。然而，与这种致动器的制造，集成，维护和操作相关的困难阻碍了它们的实用性。在这里，我们利用具有液态金属功能的泵在小型化的液体室内产生涡流。这些旋涡的配置和旋转速度可以通过调整通电电信号的极性和频率来控制。这允许在腔室内创建定制的空间温度梯度。泵中没有传统的运动元件，有利于涡旋的快速重新配置。这样可以从一种温度曲线快速过渡到另一种温度曲线，并创建自定义的时空温度梯度。这样可以使热点温度从35到62°C波动，并在15秒内在涡旋中心从25到27°C。我们的液态金属涡流发生器可以轻松制造，集成和操作，并为研究热敏材料和生物样品提供了机会。