Gas Selectivity Enhancement Using Serpentine Microchannel Shaped with Optimum Dimensions in Microfluidic-Based Gas...

Area of Science:

• Microfluidics
• Chemical Sensing
• Computational Modeling

Background:

• Microfluidic gas sensors offer advantages in size, accuracy, and cost over traditional gas chromatography and mass spectroscopy.
• Microchannel geometry is a critical factor influencing gas sensor performance, including response and selectivity.
• Multiphysics modeling provides a powerful tool for investigating complex phenomena in microfluidic devices.

Purpose of the Study:

• To simulate and compare the performance of simple and serpentine microchannel geometries for microfluidic gas sensors.
• To investigate the impact of microchannel dimensions (length, height) on gas sensor selectivity and response.
• To identify optimal microchannel geometry for enhanced microfluidic gas sensor performance.

Main Methods:

• Utilized COMSOL Multiphysics 5.6 for 3D numerical simulations of microfluidic gas sensors.
• Employed multiphysics modeling to analyze diffusion, surface adsorption/desorption, and surface reactions.
• Fabricated a polydimethylsiloxane (PDMS) serpentine microfluidic channel using a 3D printed mold for experimental validation.

Main Results:

• The simple channel geometry exhibited approximately 50% greater response but lower selectivity compared to the serpentine channel.
• Increasing microchannel length and decreasing height were found to improve gas sensor selectivity.
• A serpentine microchannel with dimensions W = 3 mm, H = 80 µm, and L = 22.5 mm was identified as optimal for high selectivity and response.

Conclusions:

• Microchannel geometry significantly impacts microfluidic gas sensor performance, with serpentine designs offering improved selectivity.
• Optimized dimensions, particularly increased length and decreased height, enhance sensor selectivity.
• The study provides a validated optimal design for microfluidic gas sensors, confirmed through simulation and experimental fabrication.