New Urea-Based Surfactants Derived from α,ω-Amino Acids

New anionic urea-based surfactants derived from α,ω-amino acids and in particular from β-alanine were synthesized and their solution properties characterized by electrical conductivity, equilibrium surface tension, and steady-state fluorescence spectroscopy techniques. Double-chain surfactants and the single-chain surfactant containing a sulfate head group exhibited the lowest critical micelle concentration (cmc) values and superior efficiency in lowering surface tension. All surfactants promoted adsorption relative to micellization, and micellar parameters were sensitive to the hydrophobicity of the amino acid residue. The polarity of the interfacial region, measured with the solvatochromic probe E T(30) (Reichardt’s betaine dye), was similar to sodium dodecyl sulfate (SDS) micelles.