Poly(Vinyl Alcohol)-Saccharide Hydrogels with Size-Tunable Plasticization-to-Reinforcement for Flexible Sensors

This study demonstrates a molecular size-dependent strategy to regulate the network structure of poly(vinyl alcohol) (PVA) hydrogels using a series of saccharides with increasing molecular size—glucose, maltose, raffinose, soluble starch, and amylose. FTIR, XPS, XRD, and TG analyses reveal that increasing saccharide size shifts the network from plasticization to reinforcement, which is further confirmed by mechanical testing and rheological analysis. Small-molecule saccharides disrupt hydrogen bonds and enhance chain mobility, while macromolecular starches promote network regularity through strong hydrogen bonding and crystallization induction. This structural tunability ndows the resulting hydrogels with integrated functionalities: tensile strain increases from 640% to 1500%, self-healing efficiency reaches up to 90.6%, and high-fidelity electrocardiogram (ECG) signal acquisition is achieved with a signal-to-noise ratio of 39.84 dB, comparing favorably with commercial electrodes. This work establishes a structure–property relationship linking saccharide molecular size to network architecture and provides a versatile material platform for next-generation flexible wearable sensors and bioelectrodes.