Dr. Sourabh Kumar

Alumni

Sourabh successfully defended his Thesis in July 2023.

Project

When polymers are exposed to mechanical stress, the structural and spectroscopic properties of the materials change, which can be used for the change in color of materials under stress or for self-healing. Many effects that emerge during mechanical deformation have not yet been understood: What are the factors that lead to material failure in a certain part of the polymer, while other parts stay intact? How can the color response be optimized to achieve a significant color change well before material failure occurs? How can self-healing processes be optimized? To answer these questions, computational methods for the description of molecules under mechanical stress are developed and applied.

Publications

1. L. J. Mier, G. Adam, S. Kumar, T. Stauch, "The Mechanism of Flex-Activation in Mechanophores Revealed By Quantum Chemistry", ChemPhysChem 2020, 21, 2402-2406.
2. S. Kumar, T. Stauch, "The activation efficiency of mechanophores can be modulated by adjacent polymer composition", RSC Adv. 2021, 11, 7391-7396.
3. S. Kumar, F. Zeller, T. Stauch, "A Two-Step Baromechanical Cycle for Repeated Activation and Deactivation of Mechanophores", J. Phys. Chem. Lett. 2021, 12, 9740-9474.

4. S. Kumar, R. Weiß, F. Zeller, T. Neudecker, “Trapping the Transition State in a [2,3]- Sigmatropic Rearrangement by Applying Pressure”, ACS Omega 2022, 7, 45208-45214.

5. S. Kumar, B. Demir, A. Dellwisch, L. Colombi Ciacchi, T. Neudecker, “Multiscale Mechano- chemical Modeling of Spiropyran-Merocyanine Isomerization in Linear PMMA Polymers”, Macromolecules 2023, 56, 8438-8447.

6. S. Kumar, "In Silico investigations of mechanophore activation in polymers", Dissertation, University of Bremen, 2023, DOI: 10.26092/elib/2357

7. Y. Appiarius, S. Míguez-Lago, P. Puylaert, N. Wolf, S. Kumar, M. Molkenthin, D. Miguel, T. Neudecker, M. Juríček, A. C. Campaña, A. Staubitz, “Boosting quantum yields and circularly polarized luminescence of penta- and hexahelicenes by doping with two BN-groups”, Chem. Sci. 2023, DOI: 10.1039.D3SC02685J

8. S. Aydonat, D. Campagna, S. Kumar, S. Storch, T. Neudecker, R. Göstl, “Accelerated mechanochemical bond scission and stabilization against heat and light in carbamoyloxime mechanophores”, ChemRxiv2024, DOI: 10.26434/chemrxiv-2024-5tfzd