Actual Visualization of Mechanical Mapping via Hofmeister Effect-Regulated Elastic Structure-Colors

Finite element analysis (FEA) is widely used for mechanical mapping in flexible sensors but lacks direct experimental validation and real-time visualization, limiting its analytical reliability. Here, we report an elastic structure-color hydrogel that enables quantitative visual mechanical mapping by integrating Hofmeister effect-regulated mechanical tunability with the structural sensitivity of photonic crystal arrays. Pressure-induced deformation is transduced into optical signals, exhibiting a blue shift from 652 to 589 nm over 0-30 kPa and a linear stress-optical response under 4-18 kPa (R² = 0.992). FEA simulations of electric-field redistribution agree well with experimental results, establishing a bidirectional simulation-experiment validation framework. The system achieves high-resolution spatial pressure mapping and 99.2% classification accuracy in biomechanical analysis. Additionally, the platform enables qualitative and quantitative drug analysis, demonstrating its versatility. This work establishes a virtual-real closed-loop analytical strategy for multimodal, quantitative sensing in flexible sensor technologies.