Flexible 3D‐Printed Cellulosic Constructs for EMI Shielding and Piezoresistive Sensing

Abstract Advances in materials science and sustainability have positioned cellulose nanofibers (CNFs) as an important nanomaterial for creating complex 3D architectures through 3D printing techniques. However, the inherent limitations of 3D‐printed CNF‐based materials, such as poor electrical conductivity and restricted mechanical flexibility, pose barriers to their application in next‐generation electronics. The research addresses these challenges by integrating CNF‐based 3D printed frameworks with a conductive polymer via a process known as “cold chemical vapor polymerization” (CCVP). The procedure initiates with the direct ink writing (DIW) of the CNF hydrogel, which then undergoes saturation with Fe ³⁺ ions and freeze‐drying to produce ion‐embedded CNF frameworks. Subsequently, interconnected conductive pathways of poly(3,4‐ethylenedioxythiophene) (PEDOT) are generated within these structures using CCVP. This methodology allows for precise customization of electrical conductivity, resulting in the production of highly conductive (546 S m ⁻¹ ) and mechanically flexible (70% compressible) patterned constructs. This advancement is highlighted by the development of grid‐based structures designed for electromagnetic interference (EMI) shields. These innovative shields demonstrate an absorbance of 0.71 and a specific EMI shielding effectiveness of 3406.45 dB cm ² g ⁻¹ . Furthermore, these aerogels function as highly sensitive piezoresistive sensors, demonstrating the versatility of this sustainable approach for advancing wearable electronics and multifunctional technologies.