electroadhesive

Electroadhesive, more commonly described as electroadhesion, is a mechanism in which an electric field induces an attractive force between surfaces, enabling dry adhesion and contact without traditional adhesives. In practical devices, a thin dielectric layer sits between conductive electrodes; when a voltage is applied, the electric field polarizes the dielectric and generates Maxwell stresses at the interface, pulling the surfaces into contact. The adhesion is rapidly switchable by applying or removing the voltage and can be modulated with alternating current signals to optimize grip and release.

Mechanism: The applied field causes charge separation across the dielectric and at the contact interfaces. The resulting electrostatic pressure increases with the square of the electric field and is enhanced by small gaps and compliant contact. The effect is strongest on dielectric, non-conductive surfaces and is influenced by electrode geometry, dielectric material, surface roughness, and humidity. Some designs use two flexible electrode sheets with a dielectric layer and operate with AC or pulsed DC to improve performance and reduce electrochemical effects at the interface.

Applications: Electroadhesive devices are used in soft robotics and micro-manipulation to pick up and place delicate or lightweight objects such as plastic films, foams, or small components, often without damage or residue. They offer dry adhesion and rapid releasability.

Advantages and limitations: The approach provides reversible, controllable adhesion without chemical bonding and without residues. Drawbacks include dependence on surface type and contamination, the need for a power supply, and typically lower grip strength on rough or conductive surfaces or at large scales, as well as voltage requirements.