Abstract
Polymer-grafted metal–organic frameworks (MOFs) address the powder form and poor processability of crystalline MOFs by forming free-standing self-assembled MOF monolayers (SAMMs). However, to date, SAMMs have been limited to microporous MOFs. Herein, we report the first successful synthesis of polymer-grafted mesoporous PCN-222 nanorods using chain transfer agent (CTA)-anchored reversible addition-fragmentation chain transfer polymerization (RAFT) polymerization of methyl acrylate (MA) and methyl methacrylate (MMA), extending SAMMs beyond microporous frameworks. Monodisperse PCN-222 nanorods were surface-functionalized and polymer grafts were grown from the particles under optimized photocatalyst conditions. PMMA grafting yields free-standing SAMMs with tunable 1D–2D rod alignment through thick external brushes and partial mesopore infiltration, while flexible PMA causes aggregation and SAMM failure due to thin surface coverage. Quantitative 13C solid-state nuclear magnetic resonance (ssNMR) reveals polymer–MOF ratios consistent with PMMA's dual surface/partial pore filling (perturbed linker peaks and relaxation), while 1H–13C HetCor with spin diffusion shows rapid initial MOF linker cross-peaks from the proximal polymer. Simulations confirm thicker PMMA brushes (∼2× PMA thickness) and significant pore filling, explaining assembly differences when compared to SAMMs derived from other MOFs (e.g., UiO-66). This work establishes polymer rigidity–mesopore interplay as a design principle for MOF–polymer hybrids, providing a foundation for future development of functional, free-standing SAMMs for catalysis, separation, and large-molecule transport applications. The infiltration of polymers in polymer-grafted metal–organic frameworks (MOFs) is investigated and the impact of the formation of free-standing self-assembled MOF monolayers (SAMMs) reported.