Solvent-resistant polyHOF membranes with well-defined nanostructures and high structural stability

Hydrogen-bonded organic frameworks (HOFs) have gained growing attention in the design and fabrication of advanced nanoporous membranes, while there have been few reports about their potential applications requiring long-term immersion of membranes in liquid, especially organic solvents. Herein, we fabricated solvent-resistant HOF@polymer (polyHOF) membranes through facile polymer network-reinforced synthesis strategy of polyHOF nanosheets, followed by vacuum filtration. Two hydrophilic polymers, polyvinyl alcohol (PVA) and polyethylene glycol (PEG), were selected to form multiple-site hydrogen bonding interactions with the pristine HOF framework. Benefiting from the reinforced hydrogen bonding networks and the electrostatic interactions between polymer chains and the HOF framework, these polyHOF membranes demonstrate exceptional stability in many solvents (even in water) for more than 30 days. Moreover, the enriched and regular channel of HOF enables the ultrafast solvent permeance (367.8 L·m⁻²·h⁻¹·bar⁻¹ to water) and precise molecular sieving (> 99.6% rejection to Evans blue). This modification technique presents a generic and promising strategy to robust HOF membranes, which can maintain high performance during long-term operation.