Dissolution behavior in water of a model hydrophobic alkali-swellable emulsion (HASE) polymer with C₂₀H₄₁ groups

Abstract

The dissolution behavior of a hydrophobic alkali-swellable emulsion (HASE) in water was examined by dynamic light scattering and pyrene fluorescence probe experiments. The HASE polymer was obtained by the copolymerization of ethyl acrylate (EA), methacrylic acid (MAA), and a macromonomer containing a C 20 H 41 group separated from the polymer backbone by 32 ethylene oxide units. The behavior of the copolymer was followed as a function of the neutralization degree α = [NaOH]/[COOH] of the MAA component. Particles swell with increasing α until α = 0.4 after which polymer dissolution begins. At low α, pyrene, added as a probe to the solution, dissolves in the EA-MAA copolymer phase; whereas at high α, pyrene is largely localized in C 20 H 41 micelles. Pyrene fluorescence measurements show that the striking viscosity increase of the solution with increasing α correlates with polymer dissolution and intermolecular network formation. Key words: associative polymer, hydrophobic substituents, polymeric micelles.