Microfluidic phase change valve with a two-level cooling/heating system

作者：Gui Lin; Yu Bo Yang; Ren Carolyn L^*; Huissoon Jan P

来源：Microfluidics and Nanofluidics, 2011, 10(2): 435-445.

DOI：10.1007/s10404-010-0683-3

• Phase change valve
• Microfluidics
• Freeze/thaw valve

A phase change (PC) microvalve with an integrated two-level cooling/heating system is developed for microfluidic applications in this article. This PC microvalve utilizes the liquid-solid PC of a small portion of the working medium in a microchannel to switch on/off the flow in the microchannel. The size of the working medium for the PC microvalve is 5-mm long, 50-mu m high, and 80-mu m wide (50 mu m x 80 mu m is the cross-sectional area of the channel) in this study. The switch is actuated by using a two-level cooling/heating system integrated on the chip. The first-level cooling/heating unit keeps the working medium in the valve area in the temperature range of supercooling state. Based on the supercooling state, the second-level cooling/heating unit either heats up or cools down the medium in the valve area to trigger its PC between liquid and solid for valving purposes. The proposed microfluidic PC microvalve is characterized experimentally in microfluidic chips. The thermal impact of one PC microvalve in one particular microchannel on its adjacent channels is discussed by establishing a preliminary analytical model and a numerical model. In addition to no leakage and no moving element, this PC microvalve with a two-level cooling/heating system can achieve a very short cooling time (i.e., 2.72 s).

• 出版日期2011-2