Formulation of Chitosan-MOF-Polymer Core–Shell Fibers for Organophosphate Hydrolysis under Nonbuffered Conditions

Metal–organic frameworks (MOFs) have been shown to facilitate organophosphate hydrolysis; however, they often necessitate amine buffers to induce high activity and turnover. While nonvolatile buffers can be integrated into MOF composites through amine polymers, solid-state MOF formulations suffer reduced organophosphate hydrolysis due to the reduction of MOF accessibility and hydrophilicity within polymer composites. Herein, we utilized the hydrophilic biopolymer chitosan in conjunction with MOFs to fabricate highly active composites for the hydrolysis of dimethyl-p-nitrophenylphosphate (DMNP) under nonbuffered conditions. In addition, we used an acrylic 3D-printed dual nozzle in the fabrication of highly reactive core–shell wet-spun fibers. This fabrication process is amenable to different core polymers and facilitates modular fiber strength and elastic properties. We demonstrate that polyelectrolyte complexation (PEC) facilitates enhanced chitosan-MOF sheath coverage of the core and consequently increases DMNP hydrolysis. To enhance chitosan-MOF sheath retention upon physical manipulation of elastic fibers, we chemically adhered the MOF-chitosan sheath to a chloromethyl-functionalized styrene-ethylene-butylene-styrene (SEBS) elastic polymer. We believe that our fabricated active fibers offer advancements for the practical and recyclable utilization of MOF composites for organophosphate protection.