Polyaniline-based materials for smart biocompatible non-invasive medical and humidity sensors and flexible all-in-one supercapacitors

Conductive polymers as polyaniline (PANI) can represent a simple and affordable answer to the necessity of flexible electronics. PANI in particular shows a peculiar doping/dedoping process, with high conductivity and tuneability, but lacks mechanically due to its fragility. However, different supports can enhance the mechanical properties of PANI, donating resilience, tenacity, and flexibility. The fabrication of different biocompatible devices based on PANI composite materials is here presented, respectively a paper-like sensor for humidity[1] and an all-in-one supercapacitor (SC).[2] PANI was polymerized with poly (2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPSA) for a more mechanically stable structure and enhanced conductivity, achieving PANI emeraldine state. Thus, when blended with cellulose fibres, the hygroscopicity of PANI provides a humidity-related conductivity increase. Consequentially, another interesting application as breath sensor and ECG was explored.[1] The application in energy storage field is then investigated with the insertion of PANI-PAMPSA in polyvinyl alcohol (PVA) hydrogel systems. PVA powder was dissolved in PANI-PAMPSA solution, inducing a physical crosslinking through freeze-thaw cycles and providing a self-healing ability to the device.[3] This all-in-one SC, completed with PVA-H2SO4 hydrogel interlayer and graphene-based electrodes, shows flexibility and durability, and it operates during and after physical deformation.[2] REFERENCES [1] I. Ragazzini et al., Carbohydrate Polymers, vol. 316, p. 121079, Sep. 2023. [2] A. Giovagnoli, G. D'Altri et al., Gels, vol. 10, no. 7, p. 458, Jul. 2024. [3] G. D’Altri et al., ACS Omega, vol. 9, no. 6, pp. 6391–6402, Feb. 2024.