By utilizing the high gas permeability of PDMS, a simple syringe-assisted micropumping method is presented. A constant, controllable pumping rate ranging from 0.3 to 4 nl/s was achieved by controlling the gap distance (g) and overlap area (S0) between a dead-end channel and a surrounded chamber. This method enables a syringe-assisted, instantaneous, recurring, point-of-care pumping system without connecting cumbersome external pumps or pre-evacuating the devices in a vacuum chamber. A dead-end channel is partly surrounded by a chamber with a thin gap distance. A glass syringe is connected with the chamber by a tube. By pulling a plunger, low pressure will be generated inside the chamber. Liquid is loaded in an inlet port after waiting a few seconds to allow constant and steady-state air flux. The pressure difference between the dead-end channel and the surrounded chamber allows air diffusion through the gas-permeable PDMS, from inside the channel to the chamber across the gap. Therefore, the fluid can be drawn inside the dead-end channel.
Journal: TechConnect Briefs
Volume: 2, Nanotechnology 2013: Electronics, Devices, Fabrication, MEMS, Fluidics and Computational (Volume 2)
Published: May 12, 2013
Pages: 305 - 309
Industry sector: Sensors, MEMS, Electronics
Topics: Modeling & Simulation of Microsystems