Spectroscopic investigations of gemini surfactants with Reichard's ET-30 dye

The solutions of gemini surfactant 1,3-bis(N-hexadecyl-N,N-dimethylammonium)propane dibromide (1) and 1,4-bis(N-hexadecyl-N,N-dimethylammonium)butane dibromide (2) were studied with a solvatochromic probe, 2,6-diphenyl-4-(2,4,6-triphenyl-1-pyridinio)phenoxide, better known as Reichard's ET-30 dye (3). The solution polarity (ET) was calculated from the wavelength maximum of the lowest-energy, intramolecular charge-transfer π-π* absorption band of 3. The obtained results indicate the presence of small clusters, formed by the association between the surfactants and 3.