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Date of Award

Spring 2012

Degree Type

Thesis

Degree Name

Master of Applied Science (MASc)

Department

Mechanical Engineering

Supervisor

P. R. Selvaganapathy

Co-Supervisor

C. Y. Ching, T. Hoare

Language

English

Committee Member

C. Y. Ching, T. Hoare

Abstract

Microdroplets have large and varied areas of application ranging from document printing to complex lab-on-chip devices. Lab-on-chip systems often require precise volume control as well as high throughput operations. Microdroplets fulfill these requirements and have become a staple in these devices. The work presented in this thesis involves the design and characterization of two individual devices capable of droplet generation utilizing flow focusing and electrogeneration methods.

The first design involved the generation of gel microdroplets utilizing the flow focusing technique. This device proved to be robust and reliable producing large volumes of uniformly mixed droplets. Long term operation of this device was analyzed and determined to be a feasible route for the manufacture of large quantities of droplets. The device was operated for over 30 hours creating gel droplets ranging from 40-200 μm in diameter with acceptable polydispersities for use in drug release studies.

The second device involved the design and characterization of a system for the electrogeneration of microdroplets. This novel device involved the injection of droplets via high voltage and high frequency signals into a cross-flow of oil. The droplet generation was characterized and different droplet generation modes were observed. With the careful selection of parameters ideal conditions were obtained to generate monodisperse droplets of sizes ranging from under 5 to over 100 μm in a highly repeatable manner.

To conclude, two separate microfluidic droplet generation devices operating in distinct modes were designed and analyzed. These devices are robust, reliable, and flexible with some applications being tested.

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