Keywords
Abstract
Microfluidic chips are critical components in numerous biomedical, chemical, and analytical applications. This study investigates the influence of femtosecond laser parameters on microfluidic channel morphology and explores methods for precise wettability control through surface chemical modification. Using ultrafast laser processing with pulse durations in the femtosecond range, we systematically varied laser fluence (0.5-10 J/cm²), scanning speed (10-500 mm/s), and pulse repetition rate (1-1000 kHz) to fabricate microchannels on polydimethylsiloxane (PDMS) and polymethyl methacrylate (PMMA) substrates. Surface characterization revealed that femtosecond laser processing not only enables precise microchannel geometry control but also induces chemical and topographical modifications that significantly alter surface wettability. By combining laser processing with subsequent chemical treatments including oxygen plasma exposure and silane-based surface functionalization, we achieved spatially resolved patterns of hydrophilic and hydrophobic regions with contact angle contrasts exceeding 120°. The developed techniques provide a versatile platform for creating microfluidic chips with tailored surface properties for applications such as droplet manipulation, cell patterning, and diagnostic assays.