Electroactive polymers

Electroactive Polymers or EAPs are polymers whose shape is modified when a voltage is applied to them. They can be used as actuators or sensors. As actuators, they are characterized by the fact that they can undergo a large amount of deformation while sustaining large forces. Due to the similarities with biological tissues in term of achievable stress and force, they are often called artificial muscles, and have possible application in the fields of robotics, where large linear movement are often needed.

EAP may take several configurations, but they can be divided in two principal classes :

• Dielectric EAP, for which actuation is due to electrostatic forces between two electrodes squeezing the polymer. This kind of EAP is characterized with large actuation voltage (several thousands volts), but very low power consumption. It requires no power to keep the actuator at a given position.
• Ionic EAP, for which actuation is due to the displacement of ions inside the polymer. A few volts are needed for actuation, but the ionic flow implies a higher electrical power needed for actuation, and energy is needed to keep the actuator at a given position