A monolithic poly(dimethylsiloxane) electrostatic actuator for controlling integrated pneumatic microsystems

Although pneumatic microvalves are widely utilized in microfluidic systems, they are rarely used in portable applications due to the bulky ancillary equipment required for their actuation. The microvalves rely on transducers that convert electrical signals into mechanical forces, and the miniaturization and integration of these transducers has proven to be challenging. Here, we report a strategy for operating pneumatic valves where microscale electrostatic actuators were used to relay commands from electronic ancillaries. Each electrostatic actuator occupied a footprint less than 0.5 mm2, and was composed entirely of poly(dimethylsiloxane) and multi-walled carbon nanotubes. Similar to typical pneumatic microvalves, the electrostatic actuators were fabricated exclusively with soft-lithographic techniques, which permitted both components to be integrated monolithically. The actuators operated at electric potentials less than 300 V, and regulated microchannels pressurized up to ~4 kPa, which is sufficient for many microfluidic applications.