Micelle formation of poly(ethylene oxide-b-sodium 2-(acrylamido)-2-methyl- 1-propane sulfonate-b-styrene) and its interaction with dodecyl trimethyl ammonium chloride and dibucaine

Micelles of a new ABC triblock copolymer, poly(ethylene oxide-b-sodium 2-(acrylamido)-2-methyl-1-propanesulfonate-b-styrene) (PEO-b-PAMPS-b-PS), were prepared in aqueous solutions. The physicochemical properties of the micelle were investigated by combining different techniques: dynamic light scattering, fluorescence spectroscopy, scanning electron microscopy, and transmission electron microscopy (TEM). The micelles have a spherical morphology with a hydrophobic PS core, a hydrophilic and anionic PAMPS shell, and a hydrophilic and nonionic PEO corona as revealed by TEM measurements. The interactions of dibucaine (DC) and dodecyl trimethyl ammonium chloride (DTAC) with PEO-b-PAMPS-b-PS were also studied. The binding of cationic DC and DTAC to the anionic PAMPS shell was confirmed by zeta-potential measurements. It is elucidated that hydrophobic interactions contribute to the binding of DTAC and DC to the polymer, although electrostatic interactions play a primarily important role. © 2010 The Royal Society of Chemistry.