Dual-stage Healing Mechanism of Dynamic PDMS Vitrimer Thin Films

Materials that combine mechanical robustness with thermo-mechanical processability are of broad interest. Vitrimers are especially attractive because they maintain network connectivity and modulus while exhibiting liquid-like plasticity through dynamic bond exchange. Such liquid-like behavior enables healing phenomena absent in permanent networks and linear polymers. Here, we investigate healing in a dyn-PDMS vitrimer using atomic force microscopy (AFM). AFM tip-induced scratches in thin films reveal lateral material motion and recovery of the original topography at room temperature, indicating unexpected local mobility relative to bulk properties. Successive AFM scans show that this mobility is governed by Laplace-pressure gradients that drive capillary flow. This work provides the first direct visualization and quantification of Laplace-pressure-driven healing in vitrimer thin films. Insights from this study can guide the design of advanced self-healing thin-film materials for thermal-interface and barrier coatings, stretchable electronics, and biomedical devices requiring adaptive behavior with enhanced chemical stability.