Agarwal Abhishek K, Dong Liang, Beebe David J, Jiang Hongrui
Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA.
Lab Chip. 2007 Mar;7(3):310-5. doi: 10.1039/b617767k. Epub 2007 Jan 3.
We present autonomously-triggered on-chip microfluidic cooling devices that utilize thermo-responsive hydrogels to adapt to local environmental temperatures. An external rotating magnetic stirrer couples with an in situ fabricated nickel impeller in these centrifugal-based microfluidic cooling devices to recirculate cooler water. Temperature-responsive hydrogels, which exhibit volumetric expansion and contraction, are integrated at the axle of the impeller. In this design, the hydrogels behave similar to an automotive clutch, to autonomously control the impeller's rotation as a function of the local environmental temperature. Therefore, the hydrogels act as both sensors and actuators and help take away the necessity for additional temperature sensing, feedback, and/or control units here. Cooling devices capable of on-chip thermal management at multiple predetermined onset operation points are realized by changes to the composition of hydrogel to alter its lowest critical solution temperature (LCST). Furthermore, the effect of magnetic stirrer frequency on the fluid cooling and flowrates for different two-blade nickel impeller designs are presented.
我们展示了自主触发的片上微流体冷却装置，该装置利用热响应水凝胶来适应局部环境温度。在这些基于离心的微流体冷却装置中，外部旋转磁力搅拌器与原位制造的镍叶轮耦合，以使较冷的水再循环。表现出体积膨胀和收缩的温度响应水凝胶集成在叶轮的轴上。在这种设计中，水凝胶的行为类似于汽车离合器，根据局部环境温度自动控制叶轮的旋转。因此，水凝胶既充当传感器又充当致动器，在此有助于消除对额外温度传感、反馈和/或控制单元的需求。通过改变水凝胶的成分以改变其最低临界溶液温度（LCST），实现了能够在多个预定起始操作点进行片上热管理的冷却装置。此外，还展示了磁力搅拌器频率对不同两叶片镍叶轮设计的流体冷却和流速的影响。
