Recyclable/reversible adhesives have attracted growing attention for sustainability and intelligence but suffer from low adhesion strength and poor durability in complex conditions. Here, we demonstrate an aromatic siloxane adhesive that exploits stimuli-responsive reversible assembly driven by π-π stacking, allowing for elimination and activation of interfacial interactions via infiltration-volatilization of ethanol. The robust cohesive energy from water-insensitive siloxane assembly enables durable strong adhesion (3.5 MPa shear strength on glasses) on diverse surfaces. Long-term adhesion performances are realized in underwater, salt, and acid/alkali solutions (pH 1-14) and at low/high temperatures (−10-90°C). With reversible assembly/disassembly, the adhesive is closed-loop recycled (~100%) and reused over 100 times without adhesion loss. Furthermore, the adhesive has unique combinations of high transparency (~98% in the visible light region of 400-800 nm) and flame retardancy. The experiments and theoretical calculations reveal the corresponding mechanism at the molecular level. This π-π stacking–driven siloxane assembly strategy opens up an avenue for high-performance adhesives with circular life and multifunctional integration.

Nanomaterials have a critical role in functional materials engineering; however, their efficient recycling, durable use, and multifunctional integration remain a huge challenge for sustainable development. Herein, we report multifunctional biophenolic nanospheres that exploit stimuli-responsive reversible assembly based on multiple directional interactions, allowing for closed-loop recycling and durability, even in complex systems of thermosets. The biobased nanospheres can serve long-term in various environments (high temperature, water, acid, surfactant solutions, etc.). By matching disassembly conditions, the nanospheres can be circularly dissociated into precursors, removed from application systems, reassembled, and reused sustainably. The corresponding mechanism is illustrated by experimental characterization and theoretical simulation. We further demonstrate the recycling and durable multifunctional effects of the nanospheres in thermoset foams. The reproducible nanospheres with diverse radical scavenging abilities endow nanocomposites with excellent mechanical enhancement, aging resistance, and durable flame retardancy. This study paves the way for tackling the pressing issue of high-value functional nanomaterial sustainability.

Fire-resistant coatings have been favored to mitigate fire threat of billion-ton flammable materials. Their durable application inevitably expects high resistance in various complex environments, however, discarded stable materials will turn...