A Biomimetic Solvatochromic Chip With Optimized Chemical Diversity for On-Site Liquid Identification

Colorimetric sensors for instant and on-the-spot identification of organic liquids have been actively developed across diverse fields such as chemical hazard inspection, manufacturing process monitoring, and beverage safety. Multi-target sensing scenarios often necessitate large-scale sensor arrays, which inevitably increase the fabrication complexity, complicate visual interpretation, and exacerbate data redundancy. Here, we present a biomimetic photonic-gustatory chip (BiPC) comprising a polyacrylate-based solvatochromic disk (PSD) array. The elastic photonic crystal PSDs generate distinct color patterns when swelled by organic solvents. To fully unlock the sensing potential, a Hansen solubility parameter (HSP) framework was developed to assess the overall swelling cross-reactivity toward target liquids, facilitating the design of a compact PSD array with HSP-guided chemical diversity and maximized inter-solvent response distinctiveness. Using intuitive pattern recognition, an HSP-optimized four-PSD array effectively differentiates solvent types and mixing ratios, homologues and isomers, as well as alcoholic beverages. Furthermore, we developed a smartphone application that integrated image capture with deep-learning-assisted cloud computing for on-site solvent identification, achieving high accuracy (97.1% across 80 liquid classes) within 30 s. The HSP framework is generalizable to the design of compact sensor arrays for various field-deployable liquid sensing scenarios.