Thermoresponsive Mucin-Inspired Polymers as a Sustainable Water Treatment Technology

Plastic pollution represents a critical threat to global ecosystems, as fragmentation generate micro- and nanoplastics (NPs) that pose unique ecological and toxicological risks. The detection and removal of NPs from aquatic systems remain a major challenge due to their nanoscale dimensions and extreme dilution. To address this, we developed multifunctional mucin-inspired, amphiphilic bottlebrush copolymers based on oligo(ethylene glycol) acrylate (OEGA) that self-assemble into micelles in aqueous solution. These copolymers exhibit a reversible, temperature-triggered sol-gel-syneresis transition, driven by the OEGA methoxy groups, that enables hydrophobic enrichment of NPs in the collapsing hydrogel matrix. Using fluorophore-labeled polystyrene NPs (PS-NPs; 20, 100, and 1000 nm) as a model system, removal efficiencies between 68-100% dependent on NP size and copolymer composition were achieved and further enhanced by activated carbon. The scalability of the approach was demonstrated by employing pre-collapsed hydrogels under passive filtration conditions, achieving capture efficiencies >70% within 24 h. Additionally, the system facilitates NP release, as the collapsed hydrogel re-dissolves upon cooling, allowing controlled NP release and recovery efficiencies up to 61% by ultracentrifugation (UC). Finally, further chemical functionalization with charged groups enabled selective dye capture, underscoring the system’s adaptability towards a modular, programmable platform for advanced water purification technologies.