Research Field 2

Michael, P., et al. Macromolecular Rapid Communications 2018, 1800376, DOI: https://doi.org/10.1002/marc.201800376.

Strategies for visualizing stress within polymeric materials are of growing interest during the past decade. Stress-sensing materials, triggered by a mechanoresponsive catalytic system based on latent copper(I)bis(N-heterocyclic carbene) mechanophores, are reported. The activation for network-based mechanocatalysts, observing “click” conversions up to 44%, while chain-extended and linear mechanocatalysts activate is detected. The developed catalysts enable “irreversible” mechanochromic systems for stress-sensing devices. Reproduced with permission. Copyright 2018©, WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Campanella, A., et al. Macromolecular Rapid Communications 2018, 1700739, DOI: http://dx.doi.org/10.1002/marc.201700739.

Adaption and self-healing are two major principles in material science, often coupled with the placement of supramolecular moieties within a material. Basic physicochemical aspects as well as new material developments in the field are described, published after a recent review in Macromolecular Rapid Communications in 2013. Reproduced with permission. Copyright 2018©, WILEY-VCH Verlag GmbH & Co. KGaA,

Chen, S., et al. Angewandte Chemie International Edition 2017, 56 (42), 13016-13020, DOI: http://dx.doi.org/10.1002/anie.201707363.

We report significant changes in the association behavior of covalent H-bonds by the phase of attached polymer chains. Depending on the aggregation state, we observed either intact H-bonds despite segregation of the phases, or macrophase separation with a larger amount of H-bonding dissociation. Reproduced with permission. Copyright 2017©, WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chen, S., et al. Chemical Communications 2017, 53 (62), 8699-8702, DOI: http://dx.doi.org/10.1039/C7CC04683A

H-Bonded semifluorinated dendritic polymer networks are generated by association of macromolecules, driven by the weak diaminopyridine (DAP) and thymine (THY) couple. Reproduced with permission of The Royal Society of Chemistry.

Yan, T., et al. Scientific Reports 2016, 6, 32356, DOI: https://doi.org/10.1038/srep32356

Reversible polymeric networks can show self-healing properties due to their ability to reassemble after application of stress and fracture. A combination of linear and nonlinear rheological measurements clearly identifies the terminal relaxation process as being responsible for the process of self-healing. Reproduced with permission. Copyright© 2016, Springer Nature.

Chen, S., et al. Accounts of Chemical Research 2016, 49 (7), 1409-1420, DOI: http://dx.doi.org/10.1021/acs.accounts.6b00174

Hydrogen bonds (H-bonds) constitute highly relevant structural units of molecular self-assembly. They bridge biological and synthetic sciences, implementing dynamic properties into materials and molecules, not achieved via purely covalent bonds. We here discuss the phase segregation of H-bonding polymers in both the solution and solid state, wherein the molecular recognition elements are based on multiple H-bonding moieties. Our studies prove that phase segregation in H-bonding polymers is an important principle, capable to generate nanostructures and dynamic properties not achieved in covalently linked polymers. The results discussed illustrate that a rational architectural design within H-bonding polymer systems in interplay with phase segregation in both the amorphous and crystalline state opens perspectives to develop artificial supramolecular systems approaching the level of complexities and properties present in nature’s biomaterials. Reproduced with permission. Copyright 2016©, American Chemical Society.

Michael, P., et al. Angewandte Chemie International Edition 2015, 54 (47), 13918-13922, DOI: http://dx.doi.org/10.1002/anie.201505678

Triggering CuAAC reaction by mechanical force enables site- and stress-specific “click” reactions. We introduce the design and realization of a homogeneous Cu catalyst able to activate through mechanical force when attached to suitable polymer chains. Based on an N-heterocyclic copper(I) carbene with attached polymeric chains of different flexibility, the force is transmitted to the central catalyst, thereby activating a CuAAC in solution and in the solid state. Reproduced with permission. Copyright 2015©, WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.