Date of Award

Summer 8-2025

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Doctor of Philosophy (PhD)

Department

Biomedical Engineering

First Committee Advisor

Caitlin Howell

Second Committee Member

Richard Corey

Third Committee Member

Onur Apul

Additional Committee Members

Brett Ellis

Aaron Brown

Abstract

Textured surfaces have diverse applications, ranging from antibacterial properties to microfluidic devices. However, fabricating textured surfaces is often complex, time-intensive, and costly. This dissertation explores the development of cost-effective, mass-manufacturable textured surfaces by leveraging technology from the Maine paper industry. Three high-value applications of these surfaces are investigated: water sensor (kL/h), water treatment (L/h), and water emulsions (µL/h). The water sensor uses a diffraction grating texture to detect chemical and biological fluids in real-time, generating distinct spectral signatures for various analytes, including dyes, microalgae species, and nickel sulfate. The sensor achieved a manual detection limit of 5 µg/mL for methylene blue dye, which improved to 3 µg/mL with deep learning techniques. Additionally, integrating the diffraction texture onto the back and sides of a glass rectangular prism water tank enabled spatial and temporal tracking of fluid dynamics, facilitating 3D visualization of water movement and mixing. For water treatment, computational modeling was employed to identify the surface texture most likely to maximize the electric field within a fluidic device. The selected texture was fabricated onto a metal shim using metal 3D printing and post-processing, demonstrating the feasibility of rapid prototyping and iterative testing before finalizing the master texture for large-scale production. Water emulsions were generated by using a microdroplet generator fabricated by Sappi. To get a contained flow through the microdroplet generator, a modular housing was designed, allowing for cleaning and reuse. The device produced water emulsions with volumes of ~100–300 pL and a coefficient of variance of ~3–20%. Performance analysis revealed that reusability was constrained by mechanical stress on the silicone layer of the housing rather than the microfluidic texture itself. Together, these results highlight the potential of mass-manufactured textures for high-value water applications, significantly improving their cost, functionality, and deployment.

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