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Abstract
The potential of sensing devices can be significantly enhanced by utilizing biodegradable polymers with adjustable mechanical, adhesion, and healing properties. In this study, adhesive films made from dopamine (DA) and citric acid (CA) modified polyvinyl alcohol (PVA) are presented. These films are exclusively derived from bio-based materials, following an environmentally friendly and easily reproducible process that is also scalable. They exhibit robust adhesion and easy detachment from various substrates, such as stainless steel (138 – 191 kPa), particularly in the presence of moisture. In contrast to the extended degradation time of pure PVA, the composite films prepared in this study show accelerated degradation under anaerobic conditions. Notably, modified biofilms (P1DA1CA1, P1DA2CA1) exhibit superior degradation compared to conventional plastic PVA, with the exception of P1DA1CA2. The slower degradation in P1DA1CA2 is attributed to the higher acidic concentration contributed by citric acid. The study delves into the morphological changes of the prepared and degraded films using scanning electron microscopy (SEM), and the degradation process is characterized through chromatographic techniques. The study suggests that dopamine (DA) and citric acid (CA) molecules penetrate the interplanar distance of P chains, as supported by powder X-ray diffraction studies, thereby expediting the degradation process. Additionally, the inclusion of CA enhances the stability of DA molecules against oxidation, increases H-bonding, and acts as a plasticizer. These synergistic interactions are further corroborated by Fourier transform infrared (FTIR), SEM, thermogravimetric analysis (TGA), and tensile studies. The introduction of DA and CA imparts self-healing properties to the films due to the presence of multiple H-bonds. Tensile studies reveal that the strength of self-healed samples approaches that of pristine samples. Overall, the findings of this study hold promise for the development of innovative, biodegradable PVA-based self-healing adhesive films with potential applications across various domains.
