Abstract
Cyclohexene, a minimally strained cyclic olefin, presents a long-standing challenge for ring-opening metathesis polymerization (ROMP) due to its inherently low ring strain energy. In this study, we present a rational monomer design framework for cyclohexene-derived monomers that leverages adaptive ring strain modulation via fused five-membered heterocycles—including carbonate, carbamate, acetal, silyl ether, and boronic ester motifs—to enhance polymerizability while enabling closed-loop recycling. Density functional theory (DFT) calculations and experimental thermodynamic analyses reveal how monomer conformation, ethenolysis ring strain energy (ERSE), and substituent effects govern ROMP thermodynamics and ring-closing metathesis depolymerization (RCMD) efficiency. An ERSE threshold of approximately 4.3 kcal/mol is identified as necessary for effective polymerization under mild conditions. Additionally, entropy differences driven by substituent flexibility significantly impact depolymerization temperature and efficiency. The resulting polymers exhibit tunable thermal properties, with glass transition temperatures ranging from −42 to 120°C and efficient depolymerization performance. This study provides practical design principles for the development of sustainable functional polymers with predictable reactivity and recyclability.
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Data availability
Detailed experimental procedures, computational details, characterization data are available from the Supplementary Information. The Cartesian Coordinates of the calculated structures are available from Supplementary Data 1. All data are available from the corresponding author upon request.
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Acknowledgements
This paper is dedicated to Professor Chulbom Lee on the occasion of his 60th birthday. This work was supported by the National Research Foundation of Korea (RS-2023-00277926; NRF-2019R1A6A1A10073887, S.H.H.) and the Korea Research Institute of Chemical Technology (Basic project, S.H.H.) funded by the Korean Government.
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K.C. performed DFT calculations of monomer structures and ERSEs and analyzed their structure–property relationships. K.C., W.C., and M.C. carried out monomer synthesis, polymerization, and polymer characterization. K.C. and B.I. conducted thermomechanical analyses of polymers. S.H.H. conceived and supervised the project. All authors contributed to the writing and revision of the manuscript.
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Choi, K., Choi, W., Chung, M. et al. C6-ROMP Enabled by Structure-Guided Monomer Design for Chemically Recyclable Polymers. Nat Commun (2026). https://doi.org/10.1038/s41467-026-70372-9
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DOI: https://doi.org/10.1038/s41467-026-70372-9
