A Reactive, pH‐Responsive, Cleavable Surfactant for Thiol‐ene Emulsion Polymerization to Make Latex Degradable and Redispersible

ABSTRACT A synthesis of a multifunction surfactant monomer (surfmer) is reported for the emulsion polyaddition of dithiol and diene monomers. Such compound features two reactive thiols, a cleavable thioester moiety and a pendant carboxylic acid. It was obtained by the reaction of 1,6‐hexanedithiol with maleic anhydride. After partial deprotonation of the acid group, this surfactant monomer (surfmer) acts as an effective stabilizer for emulsion polymerization of 1,6‐hexanedithiol with diallyl phthalate or 1,7‐octadiene. The surfactant is soluble in the monomer phase and causes a significant decrease of the water/monomer interfacial tension. The resulting linear poly(thioether) latexes were studied as regards molar mass, particle size and composition. Their properties were compared to those of a conventional latex stabilized by a static surfactant, sodium dodecyl sulfate. After flocculation at low pH, the surfmer‐stabilized latexes can be redispersed in a basic aqueous solution. In the presence of butylamine, the dried latexes are fully or partially degraded owing to thioester units along the polymer backbone.