Solvent-mediated biomimetic reversible assembly of supraparticles from polyphenol Janus nanosheets.

Achieving fully reversible disassembly-reassembly cycles in supraparticles remains a significant challenge, particularly with respect to developing methods that are facile, rapid, and require no surface functionalization. Inspired by reversible structural transition behavior of velvet worm slime, this study proposes a solvent-mediated strategy to construct recyclable supraparticles using Janus nanosheets (JNSs) as building blocks. These JNSs consist of hydrophilic polypyrogallol domains and hydrophobic alkyl chains. Combined experimental and computational simulations reveal that the JNSs disassemble into fragments (FJNSs) in hexane/ethanol mixed solvents, and solvent evaporation induces FJNSs self-assembly into supraparticles. The dynamic breakage and reformation of π-π stacking and hydrogen bonding between FJNSs upon solvent addition and evaporation endow this process with reversibility. These intermolecular interactions can be modulated by solvent ratio, polarity, and temperature, leading to the construction of supraparticles with tunable morphologies. This method is applicable to other polyphenols and on various substrates, achieving programmable and diversified construction of polyphenol-based supraparticles and a general surface modification strategy. This study provides a facile approach for the design of stimuli-responsive reversible supraparticles, with potential applications in the field of functional materials.