SUBJECT: Ph.D. Dissertation Defense
BY: Michael Toth
TIME: Tuesday, April 3, 2018, 12:00 a.m.
PLACE: Marcus Nanotechnology Building, 1116
TITLE: High Precision Control of Integrated Microfluidics for Nanomanufacturing and Fluidic Sampling
COMMITTEE: Dr. YongTae Kim, Chair (ME)
Dr. Jun Ueda (ME)
Dr. Thomas Kurfess (ME)
Dr. Peter Hesketh (ME)
Dr. Gang Bao (BioE)


Combining the engineering principles of system dynamics and control theory with biological applications of nanoparticle synthesis and organ-on-a-chip, this work aims to advance these areas of research by developing precision control systems for high-throughput synthesis and high-precision sampling, respectively. A high-precision feedback pressure control system is developed to regulate the inlet pressure of microfluidic device, controlling the flow rate, for high precision nanoparticle synthesis. Mathematical derivation and experimental validation of the pressure system are discussed, with performance achieving less than 0.5% steady-state error for long term experimental duration (3 hours) and 0.3s settling time. The pressure control system is integrated with the development of a parallelized microvortex array, designed to increase the multiplicity of microfluidic reactors in parallel for high-throughput nanoparticle manufacturing. Critical parameters (i.e., Reynolds number and precursor composition) to maintaining nanoparticle quality are assessed and factored into the development of fluidic circuit analog and computational fluid dynamic models. A robust 3-part device is fabricated for experimental validation of the design methodology. Lastly, the development of a tunable low-cost ($250) high-precision sampling device with settling times less than 0.3 seconds, overshoot less than 2%, and zero steady-state error. Mathematical derivation of the controller and microvolumetric sampler constraints are discussed. The performance is experimentally validated through various input flow profiles. The entirety of this work can potentially advance not only the clinical translation of nanoparticles and biological sampling but can additionally create high-precision experimentation in a variety of fields such as chemistry, life sciences, energy conversion, and defense.