Nanocellulose-Based Natural Polyphenol-Modified Flexible Sensing Aerogel

This paper presents an approach to enhancing nanocellulose aerogels as flexible piezoresistive sensor substrates by constructing polyphenol–metal networks within the aerogel structure. Specifically, tannic acid (TA), a plant-based polyphenol, is utilized to improve the aerogel's mechanical properties, such as compressive strength and elasticity, which are essential for durability in sensor applications. The integration of multiwalled carbon nanotubes (MWCNTs) with nanocellulose further bolsters the aerogel's electrical conductivity, with TA playing a key role in stabilizing the dispersion of MWCNTs within the nanocellulose matrix. The resulting aerogel, prepared through freeze-drying, exhibits significant improvements: a compressive strength of 316.7 kPa under 50% deformation, which is 3 times that of a pure nanocellulose aerogel, an impressive 80% elastic recovery rate, and a consistent performance under cyclic compression for 3600 s. This work offers a sustainable and straightforward approach to creating flexible sensor substrates with enhanced mechanical resilience and stable electrical properties, aligned with green material sourcing and scalability.