Surface characterization of hydrophilic functional polymer latex particles

Abstract
Surface characteristics of styrene/acrylamide/acrylic acid copolymer and styrene/2‐hydroxyethyl methacrylate/acrylic acid copolymer latexes prepared without emulsifier using potassium persulfate as initiator and their colloidal stabilities were investigated. The negative ζ‐potentials decreased with increasing the amount of acrylamide and 2‐hydroxyethyl methacrylate copolymerized. In spite of the increase in surface charge density, the negative ζ‐potentials decreased through the maximum with increasing pH. The colloidal stabilities for NaCl concentration were remarkably enhanced with increasing both pH and the amount of acrylamide and 2‐hydroxyethylmethacrylate. These results suggest that the contration and expansion of water‐soluble polymer layer surrounding the particles play an important role in the surface properties.