Effect of Interfacial Complexation of Two Oppositely Charged Polyelectrolytes for Low-Voltage Reversible Electroadhesion

Electro-adhesion offers significant advantages through its programmability and reversibility, which enable a wide range of applications in robotics. The heterojunction of two polyelectrolytes provides an effective means for the reversible control of adhesion at substantially low voltages below 10 V, whereas most traditional dielectric electro-adhesives require several kV of operating voltage. The low-voltage operation of polyelectrolyte heterojunction electro-adhesives has been commonly attributed to interfacial electrostatic interactions between oppositely charged fixed polyelectrolytes under reverse bias. However, our study demonstrates that this behavior is also governed by electrophoretically driven interfacial complex formation, rather than by electrostatic interactions only. By calculating energetic terms while excluding viscoelastic effects through contact adhesion tests, we observe correlations between charging time and adhesion energy, as well as between frequency and adhesion energy, suggesting additional interaction mechanisms beyond purely electrostatic attraction, which are attributed to electrophoretically driven interfacial complex formation.