Sensing different micellar microenvironments with solvatochromic dyes of variable lipophilicity

The UV/Vis spectral behavior of three solvatochromic N-alkyl α-pyridones of varying lipophilicity was investigated in aqueous solutions of a block copolymer at variable temperatures. The solvatochromic responses of the three analogues to the distinct microenvironments were compared and interpreted in terms of their different location in the microheterogeneous system. The interpretation was supported by 1H NMR measurements and by molecular dynamics simulations that mimicked the interactions of the dyes with the polymeric micelle in water.

Research highlights
► Analogous solvatochromic pyridones of variable lipophilicity yielded different spectra in aqueous solutions of a block copolymer at variable temperatures.
► The spectral differences were interpreted as arising from their different location inside the micelle.
► 1H NMR studies and molecular simulations supported this interpretation.
► Analogous probes of variable lipophilicity may thus be used to characterize different environments in microheterogeneous media.