Research Field I

Synthetic polymer science and click-chemistry

Modified  from the reference37 with permission. Copyright 2019©, American Chemical Society.

One traditional focus of our research group is directed to novel polymers, novel monomers and novel synthetic methodologies. Principles of organic synthesis, macromolecular chemistry and catalyst-design are addressed, aiming to precisely engineer a macromolecules’ chemical identity.1, 2-6 To this endeavor precise chain length, low polydispersities, and the desired composition and arrangement of monomers are embedded into the desired architecture. Therefore a major focus is directed on living polymerization methods, where significant effort is placed on living carbocationic polymerization (LCCP), RAFT-polymerization, nitroxide mediated polymerization (NMP), living ring-opening polymerization (ROP), ring-opening metathesis polymerization (ROMP) and anionic polymerization (LAP). Besides endgroup- and side-chain modifications of synthetic polymers and proteins, effort has been placed for “click”-based methodologies in polymer science.

Reproduced from the reference20 by permission of The Royal Society of Chemistry.
Modified with permission from the reference20. Copyright 2015©, WILEY-VCH Verlag GmbH & Co.  KGaA, Weinheim.

Being among the first ever in 20047 to apply CuAAc (copper catalyzed “click”-chemistry) in combination with living polymerization (see our first landmark paper in this field) we have developed and used CuAAc extensively during the past decades (see our selected reviews from 20075, 20084 and 20192 as examples). Based on its extremely high functional group tolerance, its robustness due to autoacceleration-effects8, 9 and chelation-assistance,10 CuAAc is currently the only truly useful click-chemistry in Barry Sharpless definition, widely applied in polymer science. It is this knowledge which ensures fast, efficient, and also reliable transformations before, during and even after polymerization. Novel developments of our research group deal with the “thio-bromo-click”-chemistry”11-13, being advantageous if biomolecules and the conjugation of polymers onto biomolecules is desired.13 Significant effort is spent to generate biohybrid-molecules, where polymer science and proteins/peptides meet, may it be as polymer-peptide-conjugates,12, 13 as polymer-protein-conjugates,14, 15 or as artificial beta-turn-mimetics.16, 17 Recent publications show the expansion of CuAAc to mechanochemically induced chemistries.18

Reproduced from the reference38 with permission. Copyright 2012©, American Chemical Society.

The synthesis of complex supramolecular architectures, able to assemble via hydrogen bonds is a longlasting topic in our group. Based on early work, where end-group-modified polymers were synthesized via LCCP-chemistry,19 the approaching RAFT-, ROP-, ADMET, and ROMP-polymerization-methods have allowed to prepare highly complex polymer architectures. It must be mentioned that now, in combination with CuAAC and “thiobromo-click”-chemistry,12nearly any functional group can be connected onto a desired polymer backbone. Recent examples are related to combinations of RAFT-polymerization bearing complex hydrogen bonds20-24, 25 and ionomers,26 ROMP-6, 7, 27, 28, combinations of ROP (N-carboxyanhydrides, 1,3-oxazolines, caprolactones/caprolactames)17, 29-33 with/without ADMET30, 34-36, NMP10, 8, 37. Only the proper combination of high-resolution mass spectrometry (ESI/MALDI-TOF), often combined with liquid chromatography is then able to proof purity of these samples and resolve their precise structure. Coupled and hyphenated techniques have been developed to this endeavor in our group (ESI/MALDI-TOF – 2D-chromatrography)38 to achieve information on complex architecture and substitution patterns or crossover-chemistries.39 Recent work focusses on complex supramolecular polymers with defined positioning of H-bonding and halogen-N interactions.20, 22, 30, 40

There has been – and still is – a longlasting tradition in living carbocationic polymerization (LCCP) in our research-group, where polyisobutylene (PIB) is prepared by living carbocationic polymerization (LCCP). PIB is one of the few and only polymers only addressable by cationic polymerization. Being one of the few truly biocompatible polymers, defined architectures of PIB-polymers (linear-19, block-41, star-,10, 41-43 endgroup-functionalized44-45, sidegroup-functionalized46, hyperbranched-,47 cyclic48, grafting-from-SiO249) are addressed in our group via LCCP, used for subsequent (biomimetic) materials16, 50-53, self-healing elastomers21, 45, 54, 55and  ionic liquids56-57. We are further developing novel PIB-polymers for advanced applications in biomedicine and technology, as biocompatible polymers, surfaces, and as self-healing materials.Recently we are exploiting PIB as 3D-printable polymer and as slow-release system for drugs.58, 59


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  2. Neumann, S., et al., The CuAAC: Principles, Homogeneous and Heterogeneous Catalysts, and Novel Developments and Applications. Macromolecular Rapid Communications 2019, 1900359, DOI:
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  7. Binder, W. H., et al., Combining Ring-Opening Metathesis Polymerization (ROMP) with Sharpless-Type “Click” Reactions: An Easy Method for the Preparation of Side Chain Functionalized Poly(oxynorbornenes). Macromolecules 2004, 37 (25), 9321-9330, DOI:
  8. Döhler, D., et al., Autocatalysis in the Room Temperature Copper(I)-Catalyzed Alkyne–Azide “Click” Cycloaddition of Multivalent Poly(acrylate)s and Poly(isobutylene)s. Macromolecules 2012, 45 (8), 3335-3345, DOI:
  9. Kargarfard, N., et al., Improving Kinetics of “Click-Crosslinking” for Self-Healing Nanocomposites by Graphene-Supported Cu-Nanoparticles. Polymers 2018, 10 (1), 17, DOI:
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  18. Adam, C., et al., The Role of Terminal Functionality in the Membrane and Antibacterial Activity of Peptaibol-Mimetic Aib Foldamers. Chemistry-a European Journal 2018, 24 (9), 2249-2256, DOI:
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  26. Chen, S., et al., Synthesis and Morphology of Semifluorinated Polymeric Ionic Liquids. Macromolecules 2018, 51 (21), 8620-8628, DOI: Chen, S., et al., Gating effects of conductive polymeric ionic liquids. Journal of Materials Chemistry C 2018, 6 (30), 8242-8250, DOI:
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