Microfluidic Flowmeter Using a Single Hot Wire

The objective of this study is the design and fabrication of a microfluidic thermal flow sensor using polymethylmethacrylate (PMMA) as a substrate. This enables the simple fabrication process of the channel structure and the sensor itself using a laser engraver/cutter machine and a solvent-based bonding process. A thin platinum wire called a Wollaston wire is directly integrated into the fluidic chip and acts as the only sensor element. The combination of this sensor and customized measurement electronics enables a measurement range at flow velocities from 4 mm/s up to 400 mm/s (volume flow rate range from 10 µL/min up to 1 mL/min).