Investigation of functional polymeric films for self-healing smart materials

This doctoral thesis aims to develop and characterize functional polymeric films for self-healing smart materials. For this purpose, ultra-thin films were prepared on various substrates using the Layer-by-Layer (LbL) method, and their healing behaviors were investigated in the presence of amphoteric healing agents (gelatin and BSA). The effects of the structural properties and free volume parameters of the films on their self-healing capabilities were evaluated. The relationship between healing behavior and free volume was examined using PALS analysis, and the effect of healing agents on the healing performance of the films was observed. Additionally, it was found that hydrophobic surfaces limited the spread of healing agents, while hydrophilic surfaces allowed better distribution of these agents, thereby accelerating the healing process. The films were observed using stereo microscopy and SEM, and it was found that films with higher free volume exhibited faster healing behavior. As the number of layers increased, healing accelerated, with 50 and 100 bilayer PEI-PAA films fully healing within 5 minutes. Films prepared with pH 10.5 PEI and pH 3 PAA began to show healing within 20 minutes in the presence of 2% gelatin and were completely repaired after 60 minutes. SEM analysis revealed that PEI-PAA films exhibited a homogeneous surface, while CHI-DSS films showed surface defects. The mechanical properties of the films were examined using DMA analysis, and it was confirmed that the films treated with gelatin were successfully healed. Overall, this study provides significant scientific and industrial contributions to enhancing the self-healing potential of functional polymeric films.