Development electrically conductive PAAm/Alg/CNC/rGO/PANI hydrogel composites and investigation their bioelectronic properties

Characterizing the effects of parameters such as the swelling ratio, composition, and applied current frequency of hydrogels is crucial for the development of flexible, stretchable, and electrically conductive hydrogels that are of importance in a variety of biomedical applications. In this study, poly(Acrylamide) (PAAm), alginate (Alg) and crystalline nanocellulose (CNC) based stretchable PAAm/Alg/CNC/rGO hydrogels containing different amounts of reduced graphene oxide (rGO) in their structure were synthesized. To increase the electrical conductivity of these hydrogels, their composites with polyaniline (PANI) were prepared. The chemical composition and morphological characterizations were performed using FT-IR and SEM analysis techniques. Since the amount of PANI formed in the structure of hydrogel composites was directly proportional to the amount of rGO in the structure, swelling, mechanical and electrical conductivity properties changed depending on the amount of rGO. The swelling ratio and mechanical strength of the PAAm/Alg/CNC/rGO/PANI hydrogel composite series varied between 38 and 50 g water/ g polymer and 76.02–375.95 kPa, respectively. The electrical conductivities of their 25% swollen states at 10−4 MHz ranged from 15.4 to 20.20 S/m. Flex sensor, smart hydrogel fingers and electrocardiogram (ECG) electrode applications were tested. The synthesized hydrogel composite systems were quite successful in these biomedical applications as bioelectronic materials.