A piezoelectric actuator is a device that converts electrical energy into mechanical motion using the piezoelectric effect. In the context of microfluidic devices, piezoelectric actuators can be used to control fluidic delivery by generating mechanical displacements that manipulate fluids within tiny channels and chambers.
Here's how a piezoelectric actuator can control fluidic delivery in microfluidic devices:
Piezoelectric Effect: Piezoelectric materials, such as certain crystals and ceramics, exhibit the piezoelectric effect, which means they can generate an electrical charge when subjected to mechanical stress or deformation, and vice versa. When an electrical voltage is applied to a piezoelectric material, it causes a deformation (strain) in the material.
Mechanical Displacement: In a microfluidic setup, a piezoelectric actuator is often integrated into the device's structure, such as a microchannel or a chamber. When an electrical signal is applied to the piezoelectric actuator, it undergoes mechanical deformation or displacement. This displacement can be controlled precisely by adjusting the applied voltage.
Fluid Manipulation: The mechanical displacement of the piezoelectric actuator is transmitted to the microfluidic structure, causing changes in the shape, volume, or dimensions of the fluidic channel or chamber. This manipulation of the fluidic structure results in the movement, mixing, or control of fluids within the microfluidic device.
Valve Operation: Piezoelectric actuators can be used to create microfluidic valves. By strategically placing and designing the actuator, it is possible to deform the channel walls or a diaphragm in such a way that the fluid flow is controlled or blocked. This enables precise control over fluid flow rates and direction.
Dispensing and Droplet Generation: Piezoelectric actuators can also be employed to dispense precise volumes of fluids or to generate droplets. The rapid deformation of a chamber or nozzle through the actuator's movement can lead to the ejection of fluid in the form of a droplet.
Mixing and Reactions: Controlled mechanical deformation induced by piezoelectric actuators can facilitate efficient mixing of different fluids within microfluidic channels. This is important for chemical reactions, sample preparation, and other applications that require thorough mixing.
Sensors and Feedback: In some cases, piezoelectric actuators can also be used as sensors to monitor the mechanical properties or forces experienced within the microfluidic device. This feedback information can be used to optimize the fluidic control process.
Overall, piezoelectric actuators offer precise and rapid control over fluidic delivery in microfluidic devices, enabling various applications in fields such as lab-on-a-chip technology, biomedical research, diagnostics, and chemical analysis.