Solvent quality dependent interactions and phase behavior of polystyrene particles with physisorbed PEO-PPO-PEO

Abstract

This work aims to understand dispersion phase behavior as a function of solvent quality and particle volume fraction for polystyrene (PS) particles stabilized with Pluronic triblock copolymer in 0.5 M NaCl. Measurements of kT interactions between a single colloidal particle and a wall with total internal reflection microscopy (TIRM) indicate a continuous evolution in particle attraction as a function of diminishing solvent quality. The directly measured potential for relatively thin Pluronic layers displays attraction reasonably predicted by Lifshitz theory using only the PS particle properties and neglecting the Pluronic layer properties. The TIRM potential is quantitatively compared with l..