Biodegradable and Free‐Standing Ag/AZO‐Chitosan Hybrid Nanocomposite: A Sustainable Approach to Piezoelectric Smart Sensor

Abstract This study demonstrates the development of a flexible, self‐supporting piezoelectric Ag/AZO‐Chitosan hybrid nanocomposite, where AZO refers to Al‐doped ZnO. The biocompatible and biodegradable chitosan foil is synthesized by a simple, low‐cost solvent casting method. Incorporation of nanophase Ag/AZO into the chitosan matrix enhances the piezoelectric responses recorded in digital voltmeter, digital storage oscilloscope (DSO), and microcontroller‐based IoT system. Among the tested compositions, the sensor with wt. 20% Ag/AZO in chitosan displays optimal piezoelectric output with a sensitivity of 2.1 mV N −1 . The device reliably integrates economical microcontroller components, enabling real‐time voltage monitoring through mobile and computer interfaces. Unlike conventional electronic sensors, which often contribute to non‐degradable waste, Ag/AZO‐Chitosan sensor is eco‐friendly and water‐dispersible. The disposability tests reveal quicker disintegration in an acidic medium occurring within 30 min and slower (over 27 days) when kept immersed in a phosphate buffer solution (PBS). Overall, this flexible piezoelectric device is environment friendly and pressure sensitive, which possesses design affordability of wearable wireless sensing.