Controlled folding of synthetic polymer chains through the formation of positionable covalent bridges


Covalent bridges play a crucial role in the folding process of sequence-defined biopolymers. This feature, however, has not been recreated in synthetic polymers because, apart from some simple regular arrangements (such as block co-polymers), these macromolecules generally do not exhibit a controlled primary structure—that is, it is difficult to predetermine precisely the sequence of their monomers. Herein, we introduce a versatile strategy for preparing foldable linear polymer chains. Well-defined polymers were synthesized by the atom transfer radical polymerization of styrene. The controlled addition of discrete amounts of protected maleimide at precise times during the synthesis enabled the formation of polystyrene chains that contained positionable reactive alkyne functions. Intramolecular reactions between these functions subsequently led to the formation of different types of covalently folded polymer chains. For example, tadpole (P-shaped), pseudocyclic (Q-shaped), bicyclic (8-shaped) and knotted (α-shaped) macromolecular origamis were prepared in a relatively straightforward manner.

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Figure 1: Covalent folding of linear synthetic polymer chains.
Figure 2: Characterization of the covalent folding process.


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The Fraunhofer Society is acknowledged for financial support. J.F.L. thanks the European Research Council for support (Project SEQUENCES). J.F.L. thanks A. Laschewsky (Universität Potsdam), C. Wieland (Universität Potsdam), P.J. Lutz (ICS Strasbourg) and M. Maaloum (Université de Strasbourg) for discussions.

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J.F.L designed the experiments, analysed the data and wrote the paper. B.V.K.J.S. and N.F. performed the experiments and analysed the data. J.F. contributed analysis tools. All authors discussed the results and commented on the manuscript.

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Correspondence to Jean-François Lutz.

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The authors declare no competing financial interests.

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Schmidt, B., Fechler, N., Falkenhagen, J. et al. Controlled folding of synthetic polymer chains through the formation of positionable covalent bridges. Nature Chem 3, 234–238 (2011).

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