Efficient fabrication of micropillars for water repellency using photolightography

This study focuses on the fabrication and characterization of SU-8-based micropillars designed for water repellency and related applications. Using SU-8 photoresist, we created micropillars with various shapes and structures on silicon wafers to achieve enhanced water-repellent surfaces. Optimal baking and exposure parameters were thoroughly evaluated, revealing that efficient fabrication requires a higher exposure dose (~800 mJ/cm²) and extended baking time (~30 minutes) compared to standard recommendations. Both SU-8-2005 and SU-8-2015 were examined for their performance under these conditions. To enhance hydrophobicity and achieve superhydrophobic properties, two different hydrophobic coatings and boehmite nanostructures were applied. Surface characterization was conducted using 3D confocal microscopy and a microgoniometer, with results demonstrating that the micropillars could increase water droplet contact angles by approximately 30° on hydrophobic surfaces, reaching a contact angle of ~149° with C4F8 coating. The application potential of these micropillars for water removal in condensation conditions was explored using Environmental Scanning Electron Microscopy (ESEM). The micropillars effectively support applications in water repellency, condensation, boiling, and particularly in droplet jumping phenomena on superhydrophobic surfaces. By optimizing the fabrication recipe, this study advances the fundamental understanding of micro- and nanoscale interactions for various applications, paving the way for future studies in water-repellent surface design and heat transfer efficiency improvements.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2024

Author dc:creator

• Faghihi, Parsa

Contributors dc:contributor

• Miljkovic, Nenad

• Micro Pillars
• Water Repellency
• Su8
• Photolithography

Statement dc:rights

• Copyright 2024 Parsa Faghihi

Language dc:language

eng, en

Handle dc:identifier

https://hdl.handle.net/2142/127341

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F127341