Starch-Based Eco-Friendly Electrolyte from Manihot esculenta for the Anodic Synthesis of Nanostructured TiO₂ Films

Developing sustainable synthesis routes for biomedical coatings is crucial to reducing toxic waste and minimizing the environmental footprint of implantable devices. Titanium dioxide (TiO₂) nanostructured films, widely investigated for biomedical and environmental applications due to their biocompatibility, high surface area, corrosion resistance, and catalytic properties, are typically synthesized using ethylene glycol-based electrolytes (EBE). However, the toxicity and persistence of ethylene glycol (EG) raise significant environmental and safety concerns. This study introduced a greener alternative to conventional EBE by employing eco-friendly colloidal suspensions of Manihot esculenta starch. The environmental performance of the proposed electrolyte was quantitatively assessed using AGREEprep metrics, yielding a significantly higher greenness score (0.56) compared to EBE (0.29). Structural and morphological analyses by FE-SEM, XRD, and Raman spectroscopy confirmed the successful formation of nanoporous TiO₂ films, with electrolyte composition playing a decisive role in pore organization. Subsequent thermal annealing promoted the crystallization of the initially amorphous oxide into the anatase phase, a feature desirable for biomedical applications. Electrochemical testing in artificial saliva demonstrated that the corrosion resistance of starch-derived TiO₂ films can be tuned by starch concentration, reaching values comparable to or exceeding those obtained with EBE. These results highlight the feasibility and advantages of starch-based electrolytes, establishing a sustainable and practical pathway for fabricating TiO₂ films tailored for biomedical applications.