(232x) Micellization and Adsorption Properties of Alkyl Polyethylene Glycol Ether Surfactants

We are interested in non-ionic surfactants in terms of their ability to stabilize oil-in-water emulsions or dislodge oil adsorbed on surfaces, on their own, and in a formulation containing other surfactants (ionic and/or non-ionic) and/or nanoparticles. Fundamental information about the surfactant micellization and adsorption behaviors in aqueous solution can be used to assess the compatibility and potential synergism with other surfactants, and the surfactant affinity to oil and mineral surfaces. We consider here a homologous series of surfactants consisting of a single-branch C10-alcohol with varying degrees of ethoxylation, and report results on the onset of micellization (cmc), micellization thermodynamics, local environment in the micelles formed in aqueous solutions, and adsorption on solid surfaces. We examine the effects on micellization of placing propylene oxide segments between the polyoxyethylene headgroup and the alkyl tail of the surfactant [1], and compare the adsorption of low-molecular weight alkyl polyethylene glycol ether surfactants to that of high molecular weight polyoxyethylene-polyoxypropylene surfactants [2-3].

[1] Sarkar, B.; Alexandridis, P. Alkyl propoxy ethoxylate "graded" surfactants in aqueous solutions: Micelle formation and structure. J. Phys. Chem. B 2010, 114 (13), 4485-4494. DOI: 10.1021/jp910939q

[2] Bodratti, A. M.; Sarkar, B.; Song, D.; Tsianou, M.; Alexandridis, P. Competitive adsorption between PEO-containing block copolymers and PEO homopolymers at silica. J. Dispersion Sci. Tech. 2015, 36 (1), 1-9. DOI: 10.1080/01932691.2014.880847

[3] Bodratti, A. M.; Wu, J.; Jahan, R.; Sarkar, B.; Tsianou, M.; Alexandridis, P. Mono- and divalent salts as modifiers of PEO-PPO-PEO block copolymer interactions with silica nanoparticles in aqueous dispersions. J. Dispersion Sci. Tech. 2015, 36 (12), 1806-1815. DOI: 10.1080/01932691.2015.1011273