Reversible\nAdhesive Film with Ultralow Dielectric\nLoss in High Frequency via Surface Anchoring of Catechol

Debonding\nof the dielectric adhesive material will make the high-frequency\ncommunication equipment unusable, leading to resource wasting and\nelectronic waste. Reversible adhesive is an ideal strategy to realize\nthe reuse of debonding devices, but the low dielectric loss requirement\nof the dielectric adhesive materials in high-frequency devices limits\nits development. Here, the surface anchoring design of catechol was\nproposed to prepare a reversible adhesive film with ultralow dielectric\nloss in high frequency. The catechol structure was linked to the end\nof polybutadiene (PB) macromolecule to synthesize catechol-terminated\nPB (PB-D). The PB-based adhesive film (PB-F) with ultralow dielectric\nloss was used as the base film, and then PB-D was sprayed on PB-F\nto form a thin layer. In the subsequent curing process, the catechol\ngroup on the surface of PB-F could be anchored by the cross-linking\nreaction between the heterogeneous PB segments. The surface modification\ntransforms the interface debonding between PB-F and copper foil into\ncohesive failure within the PB-D layer, showing a strong adhesion\nof more than 1.1 N/mm. More importantly, relying on the reversible\nhydrogen bonding of catechol structures, the debonding material can\nregain stable bonding in a mild way. Because the catechol group is\nonly distributed on the film surface, the reversible adhesive film\nkept an ultralow dielectric loss (<i>D</i><sub>f</sub> =\n2.5–2.9 × 10<sup>–3</sup>) at 10 GHz. In this work,\nan ultralow dielectric loss and reversible adhesive film with commercial\nprospects was prepared for the first time, which is expected to be\nused for simple recovery of communication substrate bonding failure.