Strong electroadhesion at low voltage enabled by nanoscale roughness

Electroadhesion conventionally relies on kilovolt potentials to bridge macroscopic gaps in many practical applications. Here, we demonstrate that the governing length scale for strong electroadhesion is not the device-level separation but the nanoscale gap distribution imposed by surface roughness. By combining boundary-element rough-contact modeling with macroscopic friction measurements on oxidized silicon interfaces, we establish a quantitative framework that predicts adhesion pressures approaching 100 MPa at voltages below 30 V. Furthermore, we uncover a strong polarity-dependent asymmetry in adhesion and friction, which we attribute to charge trapping at grain boundaries. Our findings demonstrate that strong, low-voltage electroadhesion is viable and identify mechanisms through which undesired electroadhesion can be suppressed.

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