Contributors: T. Glawdel, C. Elbuken, D. Chan, C. L. Ren
Droplet microfluidics can realize kHz throughput, which is a revolutionary technology for combinatorial high throughput testing applicable to various fields from material synthesis, disease diagnosis, drug discovery and water quality control. Normally droplet microfluidics employs two immiscible fluids to generate picoliter- to nanoliter-sized droplets or bubbles in microfluidic channel networks to perform high throughput testing. A truly functional droplet-based microfluidic platform should include the following functions: droplet generation, merging, splitting, heating and trafficking. We have systematically studied droplet generation, droplet detection and trafficking. We are also working towards heating individual droplets and using the temperature control to manipulate droplets actively while passive means have also been developed in parallel.
This study numerically and experimentally evaluates specific design modifications that contribute to:
i) Droplet trafficking in a channel network with asymmetry channel dimensions and asymmetry flow conditions.
Sorting under asymmetry channel dimensions.
ii) Droplet generation models and experiments spanning both squeeze and transitional regimes.
Images of the drop formation process for four experiments broken down into three identifiable stages: (i) lag (ii) filling (iii) necking. Silicon oil is the continuous phase and 10%wt glycerol/water the dispersed phase; other experimental data is listed beside the images.
iii) Capacitance sensor detection of droplet size, speed, and frequency.
Capacitive detection principle.
(a) Schematic and (b) optical microscope image of droplet sensor with interdigital fingers. (c) Illustration of the ideal capacitance signal obtained from the interdigital sensor.
Bibliography
T. Glawdel, C. Elbuken, C. L. Ren, "Droplet Formation in Microfluidics T-junction Generators Operating in the Transitional REgime: Part II - Theoretical and Numerical Modellin (PDF)", Phy Review E, accepted (2012).
T. Glawdel, C. Elbuken, C. L. Ren, "Droplet Formation in Microfluidics T-junction Generators Operating in the Transitional REgime: Part I - Experimental Observations (PDF)", Phy Review E, accepted (2012).
T. Glawdel, C. Elbuken, C. L. Ren, "Passive Droplet Trafficking at Microfluidic Junctions Under Geometric and Flow Asymmetries (PDF)", Lab Chip, 11 (2011) 3774-3784. [featured on cover page]
C. Elbuken, T. Glawdel, D. Chan, C. L. Ren, "Detection of Microdroplet Size and Speed Using Capacitive Sensors (PDF)", Sens Actuator A: Phys, (2011), doi:10.1016/j.sna.2011.07.007.