(179u) Micellization of Alkyl-Propoxy-Ethoxylate “Graded” Surfactants in Aqueous Solutions: Thermodynamics and Structure

The self-assembly of alkyl-propoxy-ethoxylate surfactants in aqueous solutions has been investigated with a focus on (i) the thermodynamics of micellization (critical micellization concentration; free energy, enthalpy and entropy of micellization) and (ii) the structure of the micelles (overall shape and size; local environment in the micelle core and corona) as affected by the surfactant composition (variation of degree of ethoxylation) and solvent conditions (addition of polar organic solvents). The various results are compared to those for alkyl-ethoxylate and poly(ethylene oxide)-b-poly(propylene oxide) amphiphiles with the aim to elucidate the role of the middle, propoxy, block in the novel alkyl-propoxy-ethoxylate surfactants that exhibit a ?graded? hydrophobic-hydrophilic character.