Hofmeister Ion-Specific Layer-by-Layer Selective Ion Sensors

PROBLEM: An LbL ion sensor must distinguish its target from Hofmeister neighbours that alter water structure and surface interaction in similar ways, and background salts can shift the sensor baseline even when the target is unchanged. A calibration in one background composition does not transfer to another.

SOLUTION: IBM Cloud Ideas would host a proposal capability for Hofmeister-aware LbL sensors, requiring DFT selectivity predictions, multi-ion calibration matrices, layer history, and background-composition records in each submission. Reviewers could check that selectivity was evidenced across the relevant ion series, not in a single salt.

EVIDENCE BASIS: DOCUMENTED — Hofmeister / ion-specific effects, ions ordered by effect on water structure and protein/surface interactions; Source: 1888 series, modern molecular basis. DFT via Kohn–Sham equations (Hohenberg–Kohn 1964, Kohn–Sham 1965, Nobel 1998) predicts surface-group binding; biosorption batch isotherms are textbook DOCUMENTED. LbL assembly is a room-temperature water-based alternating-layer method.