Silica Glass-Based Droplet Generation Microfluidic Chips Enabled by Femtosecond Laser: Simulation Analysis, Controllable Fabrication, and Performance Evaluation

Microdroplet technology is widely used in biomedicine, material synthesis, and the petrochemical industry due to its unique biological and mechanical properties. Silica glass has emerged as a key substrate for droplet microfluidic chips because of its excellent physical, chemical, and biocompatible characteristics. However, its intrinsic hardness and brittleness create significant challenges in fabrication. This study investigates the use of femtosecond laser processing for the fabrication of silica glass-based microfluidic devices for droplet generation. A combined approach of simulation, numerical calculations, and experimental validation is employed to investigate key factors influencing droplet size and generation frequency, including channel wall wettability and phase flow rates. The results demonstrate that femtosecond laser direct writing enables the high-precision fabrication of microfluidic structures, such as microchannels and functional features at the channel bottom and through holes. Furthermore, ultrafast laser processing allows the creation of a cross-junction microfluidic device with superhydrophobic walls, confirming its feasibility for liquid-liquid droplet generation. This work highlights the potential of femtosecond laser processing for manufacturing high-performance microfluidic devices with exceptional precision, efficiency, and functionality, providing valuable insights for advancing microfluidic applications.