Abstract
The lifetime of electrochemical gas sensors suffers from electrolyte evaporation and from the impracticality to perform recalibration. To tackle these issues, a prototype of a microfabricated gas diffusion controlling system, based on coplanar electrowetting-on-dielectric (EWOD) actuation of ionic liquid microdroplets, is presented. The system is designed to be integrated with electrochemical gas sensors to allow on-demand sealing of the sensing chamber from the environment. The MEMS device can be electrically toggled between an open and a closed state, in which the microdroplets are used to cover or uncover the openings of a perforated membrane connecting to the sensing compartment, respectively. This ON/OFF diffusion-blocking valve mechanism potentially allows for recalibration and for liquid electrolyte evaporation reduction when the sensor is not in use, thus extending the gas sensor lifetime. A one order of magnitude reduction of evaporation rate and a more than three orders of magnitude reduction of gas diffusion time were experimentally demonstrated. Ionic liquid movement can be performed with an applied AC voltage as low as 18 V, using super-hydrophobic cover plates to facilitate droplet motion. Furthermore, the shown ionic liquid micro-droplet manipulation provides a robust and low voltage platform for digital microfluidics, readily adaptable to serve different applications.
Sign-in/Register to access full text options 
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 callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
