Séminaire IPCM | Christophe Barner-K. "Photochemically Reactive Particles:..."

 PHOTOCHEMICALLY REACTIVE PARTICLES : FROM SIGLE-CHAIN NANOPARTICLES TO MICROPARTICLES
NANOPARTICLES PHOTOCHIMIQUEMENT RÉACTIVES : DES NANOPARTICULES À CHAÎNE SIGLE AUX MICROPARTICULES

Christopher Barner-Kowollik

The development and understanding of both covalent bond formation as well as dissociation remains a grand challenge in the design of photodynamic material systems. Initially, the lecture will dive into the photophysics of a range of reaction systems devised in our laboratories, exploring how their chemical response varies as a function of varying monochromatic wavelengths, establishing synergistic, antagonistic and orthogonal reactions modes. Surprisingly, the absorption spectrum is a poor indicator for photochemical reactivity, as will be demonstrated by a range of action plots on different reaction systems.  Based on the in-depth insights of our action plot analyses, we will explore how the light-responsive adaptation of polymer materials requires specific wavelengths to induce reversible covalent bond formation and dissociation. Our efforts have been devoted to pioneering a toolbox of photocycloadditions that can be triggered by lower energy visible light, while their cycloreversion functions at the least energetic wavelength, too. The lecture will showcase the latest applications of photochemistry for the generation of photochemically reactive particles, including single-chain nanoparticle (SCNP) system, whose internal structure can be dynamically adjusted by two visible orthogonal colors of light. Examples of visible light reactive SCNP for photocatalysis will be additionally highlighted. Employing sunlight, we will also explore a new platform technology for the formation of polymeric microspheres.

Selected References

1) Mundsinger, K.; Tuten, B.; Wang, L.; Neuhaus, K.; Kropf, C.; O’Mara, M. L.; Barner-Kowollik, C. Angew. Chem. Int. Ed. 2023, e202302995. https://doi.org/10.1002/anie.202302995
2) Kammerer, J. A.; Feist, F.; Ryklin, D.; Barner-Kowollik, C.; Schröder, R. R. Adv. Mat. 2023, 2211074. Delafresnaye, L.; Feist, F.; Hooker, J.; Barner-Kowollik, C. Nat. Comm. 2022, 13, 5132. https://doi.org/10.1038/s41467-022-32429-3
3) Izuagbe, A. E.; Truong, V. X.; Tuten, B.; Roesky, P.; Barner-Kowollik, C. Macromolecules 2022, 55, 9242-9248. https://doi.org/10.1021/acs.macromol.2c01467
4) Irshadeen, I.M.; Walden, S.L.; Wegener, M.; Truong, V.X.; Frisch, H.; Blinco, J.P.; Barner-Kowollik, C. J. Am. Chem. Soc. 2021, 143, 21113 - 21126. https://doi.org/10.1021/jacs.1c09419