Bio‐Based Polymer Gels: Molecular‐Macroscopic Functional Design and Promising Applications in Wearable Flexible Sensing

Wearable flexible sensors are core devices for achieving human health monitoring, human-computer interaction, and virtual reality. However, traditional rigid components struggle to fit well with the dynamic skin surface. Bio-based polymer gels (BPGs) combine the advantages of natural-sourced materials, such as flexibility, biocompatibility, and degradability. They can also achieve functionalization and performance regulation through polymer molecular-scale design and gel network structure design, making them ideal candidates for breaking through the "rigid-flexible" bottleneck and future intelligent development. This paper deeply explores the structure-performance relationships of biopolymers such as cellulose, chitin, and gelatin, the molecular-to-macroscopic functional design strategies of BPGs, and their cutting-edge applications in multi-modal flexible sensors for strain, temperature, humidity, etc. Finally, prospects and development directions are proposed for challenges. such as functional integration and performance improvement of gels, aiming to provide design ideas and guidance for next-generation functional gels and green flexible electronics.