Tajbaksh Fakhrabadi, Seyed Farzan

► Forschungsgebiet

Nitroxide‑Based Covalent Adaptable Networks for Self‑Healable Polysiloxane Composites
In recent years, increasing concerns over the sustainability and recyclability of polymeric materials have increased the demand for systems that can recover from damage, be reprocessed, and maintain long‑term performance. This project addresses this need by developing self‑healable polymer networks based on dynamic covalent chemistry. The research is carried out within the Research Training Group 3082 Engineering Covalent Bonds in Molecules and Materials (Ec=m²), which focuses on creating materials with tunable and unconventional covalent bonding.
As part of the Ec=m² framework, the project contributes to a broader effort to understand and apply weak and reversible covalent bonds in real materials. The RTG aims to design and model molecular species with controlled bonding behavior and integrate them into polymers as well as 2D and 3D materials. Weak covalent interactions play a central role in this strategy, as they offer opportunities to create adaptable, reprocessable, and more sustainable material systems.
The project specifically focuses on covalent adaptable networks (CANs) that utilize alkoxyamine‑derived nitroxide chemistry as the dynamic bonding motif. These reversible C-ON bonds enable controlled radical exchange and bond rearrangement, allowing the material to relax stress, repair damage, and undergo reprocessing under thermal or magnetothermal activation.
The research involves synthesizing tailored alkoxyamine dynamic moieties, incorporating them into flexible polymeric matrices such as polysiloxane, and embedding iron oxide nanoparticles to enable localized heating through alternating magnetic fields. By tuning the dissociation behavior of the nitroxide bonds, the project aims to create polymer composites with efficient self‑healing capabilities and extended service lifetimes.
A key part of the work is to establish structure–property relationships governing network dynamics, mechanical performance, and healing efficiency. These aspects are investigated using thermal, mechanical, and magnetic characterization methods. Overall, the project contributes both to the development of adaptable polymer materials and to RTG’s broader goals of understanding weak covalent bonds in functional systems.