Capillary Microvalve Actuation Using Thermal Expansion of Trapped Air Bubble

Abstract

In this study, we demonstrate a compact actuation mechanism of a silicon capillary stop microvalve, based on electrothermal expansion of a trapped air bubble in a chamber. The bubble is heated using an integrated aluminum microheater deposited on the silicon substrate above the air chamber. The heater occupies an area of 320 µm × 300 µm and has a resistance of 40 Ohms. By applying a 500 ms voltage pulse of 3 V amplitude we could generate a pressure sufficient to breach the capillary barrier pressure of valve, which is around 1000 Pa.

Keywords

• Lab on Chip
• micro analysis devices
• microfluidics
• capillary valves