Abstract
A room temperature liquid metal-based microvalve has been proposed in this work. The microvalve has the advantages of easy fabrication, high flexibility, and a low leak rate. By designing a posts array in the channel, the liquid metal can be controlled to form a deformable valve boss and block the flow path. Besides, through adjustment of the pressure applied to the liquid metal, the microvalve can perform reliable switching commands. To eliminate the problem that liquid metal is easily oxidized, which causes the microvalve to have poor repeatability, a method of electrochemical cathodic protection has been proposed, which significantly increases the number of open/close switch cycles up to 145. In addition, this microvalve overcomes the shortcomings of the traditional microvalve that requires an alignment process to assemble all the parts. When the valve is closed, no leak rate is detected at ≤320 mbar, and the leak rate is ≤0.043 μL/min at 330 mbar, which indicates it has good tightness. As an application, we also fabricate a chip that can control bubble flow based on this microvalve. Therefore, this microvalve has great prospects in the field of microfluidics.
Highlights
Microvalves are essential components in the field of microfluidics [1,2,3,4]
When −800 V is applied, the closing pressure of liquid metal for all angles is from 363.3 ± 5.8 mbar to
When the pressure of the liquid metal is not high enough to overcome the surface tension, the liquid metal tongue will withdraw back to its microchannel even if the water pressure is 0 mbar. These results indicate that if we want the valve to withstand more pressure, a 75◦ valve with liquid metal pressure of 400 mbar is the best choice
Summary
Microvalves are essential components in the field of microfluidics [1,2,3,4]. Microvalves can change the resistance of the fluid in the channel and the shape of the flow channel with the help of a micro-pump. The presence of microvalves greatly reduces manual labor and increases the efficiency of microfluidic control [12]. The materials of microfluidic chips are typically polydimethylsiloxane (PDMS). There are many studies on all kinds of PDMS-based microvalves, including electrostatic [13,14], electrokinetic [15], piezoelectric [16], phase change [17], electromagnetic [18], and SMA [19]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
