Thin cross-linked polymer films with multiple reversible covalent bonds are developed as a
sustainable self-restoring alternative for regular surface coatings prone to fatigue- and micro damage. In this project, novel photo-reversible covalent linking units will be synthesized that can be split and reformed multiple times by different wavelengths of light without appreciable degradation. An innovative network-design will guarantee that small damages will be repaired by a continuous re-shuffling of reversible bonds, while retaining the overall covalent network and thereby the material’s integrity.
To optimize the reversible covalent network’s performance under standard lighting
conditions, the photo-chemical characteristics of the reversible linker will be tuned to fit the solar spectrum by adjusting the chromophore’s substituents. At each step, the material development will be supported by a thorough physicochemical characterization, aiming at building-up fundamental knowledge relating to the photoreversible and thermoreversible reactions, the self-restoring process, the interactions between the materials, and structureprocessing-property relations. Advanced thermal analysis methods, including photo-DSC, AFM-based nanothermal analysis, and chip-based photo-nanocalorimetry, will be further developed to study the thermodynamics and kinetics of the photo- and thermoreversible reactions of the polymer matrix, and the (local) progress of the self-restoring reactions in thin films. Spectroscopic methods like UV-Vis spectroscopy, fluorescence spectroscopy, and infrared-spectrocopic ellipsometry will be applied for chromophore characterization and for following the reversible reactions on a molecular scale.