Tezuka, Y. Topological Polymer Chemistry: Progress of Cyclic Polymers in Syntheses, Properties, and Functions (Word Scientific, 2012).

Miao, Z. et al. Cyclic polyacetylene. Nat. Chem. 13, 792–799 (2021).

Article  CAS  PubMed  PubMed Central  Google Scholar 

Bielawski, C. W., Benitez, D. & Grubbs, R. H. An ‘endless’ route to cyclic polymers. Science 297, 2041–2044 (2002).

Article  CAS  PubMed  Google Scholar 

Haque, F. M. & Grayson, S. M. The synthesis, properties and potential applications of cyclic polymers. Nat. Chem. 12, 433–444 (2020).

Article  CAS  PubMed  Google Scholar 

Laurent, B. A. & Grayson, S. M. An efficient route to well-defined macrocyclic polymers via ‘click’ cyclization. J. Am. Chem. Soc. 128, 4238–4239 (2006).

Article  CAS  PubMed  Google Scholar 

Sun, P., Chen, J., Liu, J. A., & Zhang, K. Self-accelerating click reaction for cyclic polymer. Macromolecules 50, 1463–1472 (2017).

Article  CAS  Google Scholar 

Kapnistos, M. et al. Unexpected power-law stress relaxation of entangled ring polymers. Nat. Mater. 7, 997–1002 (2008).

Article  CAS  PubMed  PubMed Central  Google Scholar 

Pasquino, R. et al. Viscosity of ring polymer melts. ACS Macro Lett. 2, 874–878 (2013).

Article  CAS  PubMed  PubMed Central  Google Scholar 

Doi, Y. et al. Melt rheology of ring polystyrenes with ultrahigh purity. Macromolecules 48, 3140–3147 (2015).

Article  CAS  Google Scholar 

Gambino, T., Martínez de Ilarduya, A., Alegría, A. & Barroso-Bujans, F. Dielectric relaxations in poly(glycidyl phenyl ether): effects of microstructure and cyclic topology. Macromolecules 49, 1060–1069 (2016).

Article  CAS  Google Scholar 

Ziebarth, J. D. et al. Comparison of critical adsorption points of ring polymers with linear polymers. Macromolecules 49, 8780–8788 (2016).

Article  Google Scholar 

Kammiyada, H., Ouchi, M. & Sawamoto, M. A study on physical properties of cyclic poly(vinyl ether)s synthesized via ring-expansion cationic polymerization. Macromolecules 50, 841–848 (2017).

Article  CAS  Google Scholar 

Chen, B., Jerger, K., Frechet, J. M. & Szoka, F. C. Jr. The influence of polymer topology on pharmacokinetics: differences between cyclic and linear PEGylated poly(acrylic acid) comb polymers. J. Control. Release 140, 203–209 (2009).

Article  CAS  PubMed  PubMed Central  Google Scholar 

Nasongkla, N. et al. Dependence of pharmacokinetics and biodistribution on polymer architecture: effect of cyclic versus linear polymers. J. Am. Chem. Soc. 131, 3842–3843 (2009).

Article  CAS  PubMed  PubMed Central  Google Scholar 

Yamamoto, T. & Tezuka, Y. Cyclic polymers revealing topology effects upon self-assemblies, dynamics and responses. Soft Matter 11, 7458–7468 (2015).

Article  CAS  PubMed  Google Scholar 

Arno, M. C. et al. Exploiting topology-directed nanoparticle disassembly for triggered drug delivery. Biomaterials 180, 184–192 (2018).

Article  CAS  PubMed  Google Scholar 

Natansohn, A. & Rochon, P. Photoinduced motions in azo-containing polymers. Chem. Rev. 102, 4139–4175 (2002).

Article  CAS  PubMed  Google Scholar 

Xu, X. et al. The first example of main-chain cyclic azobenzene polymers. Macromol. Rapid Commun. 31, 1791–1797 (2010).

Article  CAS  PubMed  Google Scholar 

Hoskins, J. N. & Grayson, S. M. Synthesis and degradation behavior of cyclic poly(ε-caprolactone). Macromolecules 42, 6406–6413 (2009).

Article  CAS  Google Scholar 

Williams, R. J., Dove, A. P. & O’Reilly, R. K. Self-assembly of cyclic polymers. Polym. Chem. 6, 2998–3008 (2015).

Article  CAS  Google Scholar 

Josse, T., De Winter, J., Gerbaux, P. & Coulembier, O. Cyclic polymers by ring-closure strategies. Angew. Chem. Int. Ed. 55, 13944–13958 (2016).

Article  CAS  Google Scholar 

Chang, Y. A. & Waymouth, R. M. Recent progress on the synthesis of cyclic polymers via ring-expansion strategies. J. Polym. Sci., Part A: Polym. Chem. 55, 2892–2902 (2017).

Article  CAS  Google Scholar 

Wang, T.-W. & Golder, M. R. Advancing macromolecular hoop construction: recent developments in synthetic cyclic polymer chemistry. Polym. Chem. 12, 958–969 (2021).

Article  CAS  Google Scholar 

Yoon, K. Y. et al. Scalable and continuous access to pure cyclic polymers enabled by ‘quarantined’ heterogeneous catalysts. Nat. Chem. 14, 1242–1248 (2022).

Article  CAS  PubMed  Google Scholar 

Boydston, A. J., Xia, Y., Kornfield, J. A., Gorodetskaya, I. A. & Grubbs, R. H. Cyclic ruthenium-alkylidene catalysts for ring-expansion metathesis polymerization. J. Am. Chem. Soc. 130, 12775–12782 (2008).

Article  CAS  PubMed  PubMed Central  Google Scholar 

Sarkar, S. et al. An OCO3− trianionic pincer tungsten(VI) alkylidyne: rational design of a highly active alkyne polymerization catalyst. J. Am. Chem. Soc. 134, 4509–4512 (2012).

Article  CAS  PubMed  Google Scholar 

Gonsales, S. A. et al. Highly tactic cyclic polynorbornene: stereoselective ring expansion metathesis polymerization of norbornene catalyzed by a new tethered tungsten-alkylidene catalyst. J. Am. Chem. Soc. 138, 4996–4999 (2016).

Article  CAS  PubMed  Google Scholar 

Roland, C. D., Li, H., Abboud, K. A., Wagener, K. B. & Veige, A. S. Cyclic polymers from alkynes. Nat. Chem. 8, 791–796 (2016).

Article  CAS  PubMed  Google Scholar 

Wang, T. W., Huang, P. R., Chow, J. L., Kaminsky, W. & Golder, M. R. A cyclic ruthenium benzylidene initiator platform enhances reactivity for ring-expansion metathesis polymerization. J. Am. Chem. Soc. 143, 7314–7319 (2021).

Article  CAS  PubMed  Google Scholar 

McGraw, M. L., Clarke, R. W. & Chen, E. Y.-X. Synchronous control of chain length/sequence/topology for precision synthesis of cyclic block copolymers from monomer mixtures. J. Am. Chem. Soc. 143, 3318–3322 (2021).

Article  CAS  PubMed  Google Scholar 

McGraw, M. L. et al. Mechanism of spatial and temporal control in precision cyclic vinyl polymer synthesis by Lewis pair polymerization. Angew. Chem. Int. Ed. 61, e202116303 (2022).

Article  CAS  Google Scholar 

Song, Y., He, J., Zhang, Y., Gilsdorf, R. A. & Chen, E. Y.-X. Recyclable cyclic bio-based acrylic polymer via pairwise monomer enchainment by a trifunctional Lewis pair. Nat. Chem. 15, 366–376 (2023).

Article  CAS  PubMed  Google Scholar 

Culkin, D. A. et al. Zwitterionic polymerization of lactide to cyclic poly(lactide) by using N-heterocyclic carbene organocatalysts. Angew. Chem. Int. Ed. 46, 2627–2630 (2007).

Article  CAS  Google Scholar 

Guo, L., Lahasky, S. H., Ghale, K. & Zhang, D. N-heterocyclic carbene-mediated zwitterionic polymerization of N-substituted N-carboxyanhydrides toward poly(alpha-peptoid)s: kinetic, mechanism, and architectural control. J. Am. Chem. Soc. 134, 9163–9171 (2012).

Article  CAS  PubMed  Google Scholar 

Brown, H. A. & Waymouth, R. M. Zwitterionic ring-opening polymerization for the synthesis of high molecular weight cyclic polymers. Acc. Chem. Res. 46, 2585–2596 (2013).

Article  CAS  PubMed  Google Scholar 

Piedra-Arroni, E., Ladaviere, C., Amgoune, A. & Bourissou, D. Ring-opening polymerization with Zn(C6F5)2-based Lewis pairs: original and efficient approach to cyclic polyesters. J. Am. Chem. Soc. 135, 13306–13309 (2013).

Article  CAS  PubMed  Google Scholar 

Reisberg, S. H., Hurley, H. J., Mathers, R. T., Tanski, J. M. & Getzler, Y. D. Y. L. Lactide cyclopolymerization kinetics, X-ray structure, and solution dynamics of (tBu-SalAmEE)Al and a cautionary tale of polymetalate formation. Macromolecules 46, 3273–3279 (2013).

Article  CAS  Google Scholar 

Asenjo-Sanz, I., Veloso, A., Miranda, J. I., Pomposo, J. A. & Barroso-Bujans, F. Zwitterionic polymerization of glycidyl monomers to cyclic polyethers with B(C6F5)3. Polym. Chem. 5, 6905–6908 (2014).

Article  CAS  Google Scholar 

Hong, M. & Chen, E. Y.-X. Completely recyclable biopolymers with linear and cyclic topologies via ring-opening polymerization of gamma-butyrolactone. Nat. Chem. 8, 42–49 (2016).

Article  CAS  PubMed  Google Scholar 

Zhu, J. B., Watson, E. M., Tang, J. & Chen, E. Y.-X. A synthetic polymer system with repeatable chemical recyclability. Science 360, 398–403 (2018).

Article  CAS