Abstract
Microscopic sequences of synthetic polymers play crucial roles in the polymer properties, but are generally unknown and inaccessible to traditional measurements. Here we report real-time optical sequencing of single synthetic copolymer chains under living polymerization conditions. We achieve this by carrying out multi-colour imaging of polymer growth by single catalysts at single-monomer resolution using CREATS (coupled reaction approach toward super-resolution imaging). CREATS makes a reaction effectively fluorogenic, enabling single-molecule localization microscopy of chemical reactions at higher reactant concentrations. Our data demonstrate that the chain propagation kinetics of surface-grafted polymerization contains temporal fluctuations with a defined memory time (which can be attributed to neighbouring monomer interactions) and chain-length dependence (due to surface electrostatic effects). Furthermore, the microscopic sequences of individual copolymers reveal their tendency to form block copolymers, and, more importantly, quantify the size distribution of individual blocks for comparison with theoretically random copolymers. Such sequencing capability paves the way for single-chain-level structure–function correlation studies of synthetic polymers.
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Data availability
All data are available in the main text or the Supplementary Information. Raw data supporting the findings of this study are available upon reasonable request. Source data are provided with this paper.
Code availability
MATLAB codes are included in Supplementary Software 1.
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Acknowledgements
This research was supported by the Army Research Office (grant no. W911NF-18-1-0217). R.Y. acknowledges support from a Cornell Presidential Postdoctoral Fellowship. This work made use of the NMR and Chemistry Mass Spectrometry Facilities at Cornell University, which is supported, in part, by the National Science Foundation (NSF) under award CHE-1531632. The research was carried out using Cornell Center for Materials Research Shared Facilities supported by the NSF (grant no. DMR-1719875).
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Contributions
R.Y. improved the experimental design, performed imaging experiments and bulk polymerization, coded software, analysed data and performed simulations. X.S. designed, synthesized and characterized the caged monomers, characterized the monomer uncaging and polymerization reactivity, and performed early imaging experiments. X.M. developed the data analysis pipeline, coded software and analysed data. F.S.A. synthesized and characterized the catalyst labelling reagent. S.B. contributed to the bulk polymerization experiment and NMR characterization. C.L. contributed to early-stage data analysis. G.W.C. contributed to discussions. R.Y. and P.C. wrote the main text. R.Y., X.S., X.M., F.S.A. and P.C. wrote the Supplementary Information. P.C. conceived and directed the research.
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Cornell University has filed a US patent application (no. 18/144,022) with P.C., R.Y., X.S. and X.M. as inventors, based on this research, including the methodology and potential applications. The remaining authors declare no competing interests.
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Nature Chemistry thanks Johan Hofkens and the other, anonymous, reviewer for their contribution to the peer review of this work.
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Supplementary Information
Supplementary Figs. 1–43, Discussion, Tables 1–3 and Schemes 1–6.
Supplementary Software 1
Software for data analysis and simulation.
Source data
Source Data Fig. 1
Normalized spectra (1g-h) and time-intensity raw data (1i).
Source Data Fig. 2
Positions of marker particles/catalysts (2a,e,i,j); background-subtracted fluorescence trajectory (2b-c,f,g); raw data of histograms (2d,h).
Source Data Fig. 3
Statistical source data and averaged data for kinetics (3a-b,e-f), raw data for histograms (3c-d).
Source Data Fig. 4
Positions of marker particles/catalysts (4a); background-subtracted fluorescence trajectory (4b); raw data for histograms (4d); statistical source data or averaged data (4e-j).
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Ye, R., Sun, X., Mao, X. et al. Optical sequencing of single synthetic polymers. Nat. Chem. 16, 210–217 (2024). https://doi.org/10.1038/s41557-023-01363-2
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DOI: https://doi.org/10.1038/s41557-023-01363-2
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