Three-Dimensional-Printed Polyethylene Glycol Diacrylate-Polyaniline Composites by In Situ Aniline Photopolymerization: An Innovative Biomaterial for Electrocardiogram Monitoring Systems

Three-dimensional (3D) printing technology is one of the additive manufacturing (AM) technologies that brings exciting prospects to the realm of conjugated polymers (CPs) and organic electronics through vastly enhanced design flexibility, structural complexity, and environmental sustainability. However, the use of 3D printing for CPs is still at early stages and remains full of challenges. Therefore, an interesting approach is to produce 3D-printed electrically conductive materials by exploiting the photopolymerization of conjugated monomers directly during the stereolithography process. The idea proposed in this work is to formulate a printable ink containing aniline able to photopolymerize within the insulating printable polyethylene glycol diacrylate (PEGDA) polymeric matrix directly during the 3D-printing process. The produced PEGDA-polyaniline (PANI) composites exhibit suitable morphological and structural features, as well as electrical and electrochemical performances potentially useful for various soft electronics applications. As a proof of concept, the 3D printed PEGDA-PANI samples are employed as a soft electrode in an electrocardiogram (ECG) device, and the efficiency is monitored under real-time conditions. The collected data exhibit reproducible ECG patterns, opening the way to 3D printed PEGDA-PANI electrodes for biosignal monitoring applications.