Demonstration of an integrated electroactive polymer actuator on a microfluidic electrophoresis device

The construction of microfluidic devices from siloxane-based polymers is widely reported in the current literature. While the use of these materials is primarily due to their rapid and facile fabrication, low cost and robustness, they also have the ability to function as smart materials. This feature, however, has not been commonly exploited in conjunction with their fluid-handling capabilities. Siloxanes are considered smart materials because their shapes can be modified in the presence of an electric field. The energy in the electric field can be transduced into mechanical energy and directly coupled with a microfabricated channel network in order to affect or initiate the movement of fluids. Here, we present a novel microfluidic device into which an electroactive polymer (EAP) actuation unit is integrated. The EAP actuation unit features a microfluidic channel placed above a patterned electrode. The patterned electrode is insulated from the channel by an EAP layer that is composed of PDMS. When a potential is applied across the EAP layer, it changes shape, which also changes the volume of the microfluidic channel above it. With this proof-of-concept device we demonstrated the ability to inject plugs of sample on a standard electrophoresis cross chip solely by changing the magnitude of the electric field between the channel and the electrode. Using an EAP actuation unit, the size of the injection plugs can be varied as a function of the electric field, the active area of the EAP actuation unit and the softness of the EAP.