Polyelectrolyte-induced H-aggregation of Merocyanine 540 and its application in metal ions detection as a colorimetric sensor

- H-aggregates of MC 540 was formed with assistance of PEI in aqueous solution.
- The dye aggregation were controlled with MC 540 and PEI concentration along with pH and metal ions.
- The presence of Ni2+, Cu2+, Al3+, Fe3+, Sn4+ prevented forming H-aggregates of MC 540 and triggered its H-dimer structure.
- The conversion of H-aggregates into H-dimer was used for the detection of Ni2+, Cu2+, Al3+, Fe3+, Sn4+ as a calorimetric sensor.