Dynamic switching of interfacial phenomena for heat transfer and water management
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Authors
Parisi, Gregory
Issue Date
2024-05
Type
Electronic thesis
Thesis
Thesis
Language
en_US
Keywords
Mechanical engineering
Alternative Title
Abstract
Chemical composition and physical texturing are two key aspects that determine the wetting characteristics of materials. Understanding the interaction between materials and fluids is critical in various applications, including self-cleaning surfaces, microfluidic devices, oil-water separation, water collection, and thermal management. Smart materials possess advanced interfacial super-wettable properties capable of reversibly switching between non-wetting and superwetting states. This dissertation centers on the interaction between interfacial behavior and switchable wettability, with a specific emphasis on heat transfer and water management.In the first part, a novel coating is introduced, demonstrating the reversible switching between wetting states through the application of pH as an external stimulus. This coating selectively separates water, oil, and water-in-oil emulsions, offering potential advancements in oil-water separation processes and oil spill clean-up. Additionally, a single-step sintering process is explored for optimizing the separation flow rate and efficiency of a tailorable membrane.
The second part focuses on utilizing a switchable surface for thermal management. Unlike previous studies concentrating on the evaporation kinetics of either hydrophobic or hydrophilic surfaces, this research investigates the evaporation of liquids on a surface capable of possessing both wetting properties. A theoretical model is developed to calculate evaporation kinetics using calorimetry, particularly beneficial when resolving droplet boundaries becomes challenging with conventional goniometer profiler methods. Also focusing on thermal management, this work developed a dynamic window that can switch fluid-fluid wetting properties with a temperature stimulus, regulating light transmittance for indoor self-cooling applications.
The final part of the dissertation introduces meshes and harps developed through an electrospinning technique, creating switchable fibers for fog water harvesting. These electrospun fibers, incorporating titanium dioxide (TiO2), switch wetting states in response to UV light stimuli. The modified wetting properties enhance fog capture capabilities, particularly in adverse fog conditions where conventional mesh collectors may underperform. The investigation also reveals promising results in improving fog water collection through the manipulation of the collector's macrostructure. This dissertation contributes valuable insights into the interfacial dynamics of smart materials, offering a comprehensive exploration of switchable surfaces and their potential applications in heat transfer and water management. The findings pave the way for advancements in diverse fields, ranging from environmental remediation to energy-efficient building technologies to sustainable water sources.
Description
May2024
School of Engineering
School of Engineering
Full Citation
Publisher
Rensselaer Polytechnic Institute, Troy, NY