TY - JOUR A1 - Eisenreich, F. A1 - Kathan, M. A1 - Dallmann, A. A1 - Ihrig, S. P. A1 - Schwaar, Timm A1 - Schmidt, B. M. A1 - Hecht, S. T1 - A photoswitchable catalyst system for remote-controlled (co)polymerization in situ JF - Nature Catalysis N2 - The fundamental properties of a polymeric material are ultimately governed by its structure, which mainly relies on monomercomposition and connection, topology, chain length, and polydispersity. Thus far, these structural characteristics are typicallyset ex situ by the specific polymerization procedure, eventually limiting the future design space for the creation of moresophisticated polymers. Herein, we report on a single photoswitchable catalyst system, which enables in situ remote controlover the ring-opening polymerization of l-lactide and further allows regulation of the incorporation of trimethylene carbonateand δ -valerolactone monomers in copolymerizations. By implementing a phenol moiety into a diarylethene-type structure,we exploit light-induced keto–enol tautomerism to switch the hydrogen-bonding-mediated monomer activation reversiblyON and OFF. This general and versatile principle allows for exquisite external modulation of ground-state catalysis of a livingpolymerization process in a closed system by ultraviolet and visible light and should thereby facilitate the generation of newpolymer structures. KW - Polymers PY - 2018 DO - https://doi.org/10.1038/s41929-018-0091-8 SN - 2520-1158 VL - 1 IS - 7 SP - 516 EP - 522 PB - Nature CY - London AN - OPUS4-45407 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kathan, M. A1 - Kovaricek, P. A1 - Jurissek, Ch. A1 - Senf, A. A1 - Dallmann, A. A1 - Thünemann, Andreas A1 - Hecht, S. T1 - Control of Imine Exchange Kinetics with Photoswitches to Modulate Self-Healing in Polysiloxane Networks by Light Illumination JF - Angewandte Chemie International Edition N2 - Various aldehyde-containing photoswitches have been developed whose reactivity toward amines can be controlled externally. A thermally stable bifunctional diarylethene, which in its ring-closed form exhibits imine formation accelerated by one order of magnitude, was used as a photoswitchable crosslinker and mixed with a commercially available amino-functionalized polysiloxane to yield a rubbery material with viscoelastic and self-healing properties that can be reversibly tuned by irradiation. KW - Polymer KW - Self-healing KW - Rheology KW - Nanotechnology PY - 2016 DO - https://doi.org/10.1002/anie.201605311 SN - 1433-7851 (print) SN - 1521-3773 (online) VL - 55 IS - 44 SP - 13882 EP - 13886 PB - Wiley-VCH Verlag GmbH CY - Weinheim AN - OPUS4-37904 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -