High-Speed Microfluidic Mixers for Controllable Nanoparticle Synthesis

Author

Avery EnglandFollow

Date of Award

Summer 8-2025

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

First Committee Advisor

Rosemary Smith

Second Committee Member

Scott Collins

Third Committee Member

Tomas Marangoni

Additional Committee Members

Michael Mason

Robert Meulenberg

Carl Tripp

Abstract

The design, fabrication, simulation, and experimental characterization of two high-speed microfluidic mixers are presented. The mixers were engineered to achieve rapid mixing (< 1 ms), enabling control over kinetically-limited chemical reactions, such as ultra-small nanoparticles, i.e. particles with diameters less than 3 nm. The properties of ultra-small nanoparticles are determined by their size. Therefore, controlling size is of the upmost importance for applications such as electronics, catalysis, and photonics. Of the noble metal particles, ultra-small silver nanoparticles (uAgNPs) are particularly difficult to controllably synthesize due to their sub-millisecond reaction kinetics. Chemical methods reported in the literature are ineffective at synthesizing primary shell Ag₁₃ particles without bulky ligands, which provide high stability, but make them unsuitable for many applications. This work presents two scalable and reproducible methods for producing ultra-small AgNPs, including primary shell Ag₁₃ particles, through precise control of mixing conditions, reaction time, and reagent concentrations, thereby overcoming the challenges associated with traditional synthesis routes.

Recommended Citation

England, Avery, "High-Speed Microfluidic Mixers for Controllable Nanoparticle Synthesis" (2025). Electronic Theses and Dissertations. 4223.
https://digitalcommons.library.umaine.edu/etd/4223