Abstract
In microfluidics, electric fields are widely used to assist the generation and the manipulation of droplets or jets. However, uncontrolled electric field can disrupt the operation of an integrated microfluidic system, for instance, through undesired coalescence of droplets, undesired changes in the wettability of the channel wall or unexpected death of cells. Therefore, an approach to control the distribution of electric fields inside microfluidic channels is needed. Inspired by the electro-magnetic shielding effect in electrical and radiation systems, we demonstrate the shielding of electric fields by incorporating 3D metallic coils in microfluidic devices. Using the degree of coalescence of emulsion drops as an indicator, we have shown that electric fields decrease dramatically in micro-channels surrounded by these conductive metallic coils both experimentally and numerically. Our work illustrates an approach to distribute electric fields in integrated microfluidic networks by selectively installing metallic coils or electrodes, and represents a significant step towards large-scale electro-microfluidic systems.
Highlights
Electric fields are frequently used in droplet-based microfluidics to assist the droplet generation and manipulation [1,2,3]
Emulsion droplets tend to coalesce in the presence of an applied electric field
We showed that the inserted metallic coil can successfully shield an electric field and prevent touching droplets from coalescence
Summary
Electric fields are frequently used in droplet-based microfluidics to assist the droplet generation and manipulation [1,2,3]. The interfaces of fluids are polarized or charged These charged interfaces experience an electric stress, which is quantified as the multiplication of an electric field’s strength, E, by electric charges, Q: FE = E Q. The electric stress can cause the coalescence of neighboring emulsion droplets [7,8]; this phenomenon is often known as electro-coalescence and is frequently utilized in applications including triggered chemical reaction [9], injection of liquid contents into stabilized droplets [1,10], droplet mixing [3] and characterization of emulsion stability [11]. We insert segments of a microfluidic channel into a 3D metallic coil to shield the electric field. Our approach in shielding electric fields using a 3D metallic coil will provide a simple and effective approach to tailor electric fields in sophisticated and integrated microfluidic devices for droplet-based engineering involving electric fields
Sign-in/Register to view highlights & summary 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.
