Date of Graduation
5-2024
Document Type
UAF Access Only - Thesis
Degree Name
Bachelor of Science in Chemistry
Degree Level
Undergraduate
Department
Chemistry & Biochemistry
Advisor/Mentor
Fritsch, Ingrid
Committee Member/Reader
Dong, Bin
Committee Member/Second Reader
Muldoon, Timothy
Committee Member/Third Reader
Lessner, Faith
Abstract
As small-scale “lab-on-a-chip” devices become more prevalent for chemical and biological analysis, it is critical to have precise control of small volumes of solutions. A relatively new microfluidic technique is redox-magnetohydrodynamics (R-MHD), which utilizes the force produced by an ionic current in the presence of a magnetic field to propel solution. This project sought to determine the extent to which nanoliter volumes can be manipulated by R-MHD. The chip design used in this study features two, parallel linear arrays of nine microelectrodes, each of which can be individually addressed and modified with the conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT) to convert an externally-applied electric current into ionic current within the solution without bubble formation or electrode corrosion and allow compatibility with a wide variety of liquid conditions. Strategic activation of these PEDOT-modified microelectrodes to produce various magnitudes and directions of ionic current over a permanent magnet can generate fluid flow with different speeds, paths, and profiles that redirect, split, or combine solutions. The prospects for electrodeposition of PEDOT onto the small microelectrodes that are in close proximity to each other while retaining their individuality was explored, and the R-MHD pumping capacity of the resulting system was characterized. A “magnet-switching” device was automated to sustain R-MHD fluid flow in a single direction, indefinitely extending the maximum pumping duration of the system. These studies of the fluid flow profiles at the nanoliter scale are motivated by possible applications in lab-on-a-chip devices, including chemical separations and sampling, chemical synthesis, and point-of-care analysis utilized in healthcare.
Keywords
microfludics, ethylenedioxythiophene, PEDOT, microelectrodes, particle velocimetry, magnet switching
Citation
Johnson, J. (2024). Maximizing the capability of a poly(3,4-ethylenedioxythiphene) (PEDOT)-modified microelectrode array for manipulating fluids with redox-magnetohydrodynamics (R-MHD) for applications in chip-based chemical analysis. Chemistry & Biochemistry Undergraduate Honors Theses Retrieved from https://scholarworks.uark.edu/chbcuht/52