Bono Shinji, Konishi Satoshi
Department of Mechanical Engineering, College of Science and Engineering, Ritsumeikan University, Kusatsu, 525-8577, Japan.
Graduate Course of Science and Engineering, Ritsumeikan University, Kusatsu, 525-8577, Japan.
Sci Rep. 2022 Aug 12;12(1):13733. doi: 10.1038/s41598-022-18008-y.
We proposed the detection mechanism of the micro-levels of temperature gradient in a micro-electromechanical system using the unidirectional rotation of cholesteric-liquid crystal (Ch-LC) droplets. Ch-LC droplets in the presence of an isotropic phase subjected to a heat flux rotate with a speed proportional to the magnitude of the temperature gradient. We further quantified the temperature gradient-to-torque conversion efficiency to apply the thermomechanical cross-correlation to the detection of temperature gradient. Then, we observed the rotational behavior of Ch-LC droplets after introducing them onto model devices containing patterned Au thin-film electrodes. Direct electric current applied to these Au electrodes results in unidirectional rotation of the Ch-LC droplets in response to heat flux generated from the Au electrodes. By evaluating the possible temperature gradient detection resolution using Ch-LC droplet rotation, we show that Ch-LC droplets can achieve both high spatial resolution (~ 10 µm) and high detection accuracy (~ 0.1 mK/µm).
我们提出了一种利用胆甾相液晶（Ch-LC）液滴的单向旋转来检测微机电系统中微尺度温度梯度的机制。在存在各向同性相且受到热通量作用的情况下，Ch-LC液滴会以与温度梯度大小成正比的速度旋转。我们进一步量化了温度梯度到扭矩的转换效率，以便将热机械互相关应用于温度梯度检测。然后，我们将Ch-LC液滴引入到包含图案化金薄膜电极的模型器件上后，观察了它们的旋转行为。施加到这些金电极上的直流电会导致Ch-LC液滴响应金电极产生的热通量而单向旋转。通过评估使用Ch-LC液滴旋转可能实现的温度梯度检测分辨率，我们表明Ch-LC液滴可以实现高空间分辨率（约10 µm）和高检测精度（约0.1 mK/µm）。
