Ti-Cu dry electrodes for biomedical sensing: Tribocorrosion performance under simulated skin conditions

Monitoring electromyographic (EMG) activity is crucial for diagnosing musculoskeletal disorders and understanding neuromuscular systems. Dry electrodes represent a significant advancement over traditional wet electrodes by eliminating the need for gels, thereby extending lifespan, simplifying skin preparation, and facilitating prolonged remote monitoring. However, challenges such as higher impedance and susceptibility to motion artifacts, along with issues of user discomfort and signal distortion, persist with existing metal-coated or entirely metal dry electrodes. This study explores an alternative approach using Ti-Cu thin films deposited on polymeric substrates to enhance electrical, electrochemical, and tribo-electrochemical properties. The research specifically investigates the corrosion and tribocorrosion behaviour of these Ti-Cu thin films in an artificial sweat environment, comparing them to pure Ti and Cu films. Chemical, microstructural, topographical, and electrical characterizations were conducted, alongside evaluations of electrochemical and tribo-electrochemical behaviour. The results indicate that while all films showed rupture under sliding, TiCu 0.34 thin films exhibited superior corrosion resistance due to their unique microstructure. This study suggests that TiCu 0.34 electrodes may offer a promising balance between corrosion resistance and electrical performance for wearable applications, although improvements in adhesion are necessary to withstand mechanical loads.