Electrodeposited Piezoelectric Chitosan Films: A New Approach Toward a Scalable and Standardized Fabrication of Sensors

The employment of piezoelectric sensors is exponentially increasing in a wide range of applications, from automotive to healthcare, due to their characteristic combination of sensitivity, lightweight, and low cost. The increasing demand for such devices pushes to overcome current fabrication processes’ drawbacks, seeking for more eco‐friendly as well as scalable approaches. In this regard, this work explores for the first time electrodeposition as a method to employ chitosan, a common bio‐based polymer, for fabricating piezoelectric films. In particular, gold‐coated silicon plates, acting as substrate, are immersed in a chitosan solution and subjected to different electrodeposition conditions to obtain thin films. The films are thus characterized to identify the key parameters that influence the fabrication process, influencing in turn the material structure and its piezoelectric properties. Specifically, investigation by polarized light microscopy and X‐ray Diffraction is conducted to assess the semi‐crystalline and partially ordered nature of chitosan, whereas Piezo‐response Force Microscopy is employed to estimate the piezoelectric efficiency of the films. The optimization of the electrodeposition process made it possible to achieve a d 33 piezoelectric coefficient as high as 29.52 pC N −1 , while improving scalability and standardization of fabrication, thereby encouraging a green transition in the sensors’ industry.