Author ORCID Identifier
https://orcid.org/0000-0003-1504-1932
Date Available
6-1-2026
Year of Publication
2025
Document Type
Doctoral Dissertation
Degree Name
Doctor of Philosophy (PhD)
College
Engineering
Department/School/Program
Mechanical Engineering
Faculty
Christine A. Trinkle
Faculty
Jonathan Wenk
Abstract
Precise fluid transport through microscale geometries can help optimize electrochemical and biochemical processes by maximizing the mass transfer rate of reactants. By introducing intricate structural features inside microchannels, it is possible to manipulate the fluid motion and direct the flow towards any surface of interest. In this study, we have demonstrated that rationally designed fluid pathways can improve the performance of electrochemical and biochemical systems.
The emergence of additive manufacturing has enabled rapid fabrication of robust structures with intricate features to guide fluid motion. However, their application in nonaqueous electrochemical systems has been limited due to their interaction with organic solvents. We first explored the chemical compatibility of common additive manufacturing polymers with organic solvents frequently used in electrochemical energy storage devices. Results indicated that some polymers may not swell excessively after immersing in a solvent, yet this interaction can significantly alter the mechanical properties of the polymer. Hansen solubility parameters were utilized to explain the interactions observed in the swelling study. This study proposes a systematic guideline for material screening for additively manufactured batteries, along with a chemical compatibility chart that can serve as a practical reference tool.
We then demonstrated a proof-of-concept novel pumpless redox flow cell, which was tested using a nonaqueous organic electrolyte and fabricated using the polymer selected through the compatibility study. This passively driven cell was operated by sinusoidal motion, and the interior geometry ensured that the liquid electrolyte was guided towards the flowfield-electrode region. We have revealed that lower oscillation rates induce higher mass transfer in the porous electrode, resulting in lower area-specific resistance and higher current density. As oscillation rates were increased, the amplitude of the current response during potentiostatic hold went down. Using the optimized operating parameters, this flow cell was successfully run for 100 cycles, proving its robustness over long-term operations.
We have then improved the performance of a zinc finger protein-based direct DNA detection mechanism by employing a low-cost, easy-to-fabricate colorimetric microfluidic chip. Capillary action within an absorbent material at the outlet was used to drive reagents and rapidly displace existing volumes across the microchannel of this chip. This chip was then demonstrated to be highly specific in detecting target DNA sequence, with a sensitivity of 25 pM. By increasing the surface retention of capture probes through covalent bonding and by lowering the surface area-to-volume ratio, the limit of detection was successfully improved by 200-fold compared to past work on this assay.
Digital Object Identifier (DOI)
https://doi.org/10.13023/etd.2025.554
Funding Information
This material is based upon work supported by the National Science Foundation under Cooperative Agreement No. 1849213. Title: "Kentucky Advanced Manufacturing Partnership", Years: 2021-2024
Recommended Citation
Bhuiyan, Shaikh Al Mahmud, "FLUID PATHWAYS FOR ENHANCED MASS TRANSFER IN THE MICRO REGIME: APPLICATIONS IN NOVEL PUMPLESS REDOX FLOW CELL AND ZINC FINGER PROTEIN-BASED DNA DETECTION" (2025). Theses and Dissertations--Mechanical Engineering. 251.
https://uknowledge.uky.edu/me_etds/251
