Ion-Containing Bottlebrush Elastomers as Pressure-Sensitive Electroadhesives

Abstract

Abstract This study presents a materials-design framework for low-voltage pressure-sensitive electroadhesives based on ion-containing bottlebrush polymers that combine the on-demand reversibility of traditional electroadhesives with the tunable conformability typical of pressure-sensitive adhesives (PSAs). Two complementary bottlebrush polymers bearing pendant flexible side chains and independently tunable anionic or cationic groups were designed to form soft and tough elastomers after cross-linking. When the two oppositely charged bottlebrush networks were brought into contact, a smooth, continuous interface formed, which is locally charge neutral due to the presence of mobile counterions. At low voltages (≤ 2 V), mobile ions migrate toward the electrodes, creating an interfacial heterojunction and significant electrostatic attraction that enhances adhesion, yielding an on/off ratio of up to more than 4.5. The low-voltage operation and PSA-like mechanics of bottlebrush electroadhesives, even at a charge density as low as 18 C/g, create opportunities in applications such as soft robots, haptic devices, and biomedical devices.