Polystyrene latex particles bearing primary amine groups via soap-free emulsion polymerization

Polystyrene latexes were prepared in the presence of an amino-containing functional comonomer, N-(3-aminopropyl)methacrylamide hydrochloride (APMH), via soap-free batch emulsion polymerization initiated by the cationic initiator 2,2′-azobis(2-amidinopropane) dihydrochloride. These latexes were characterized by studying the influence of the ionic comonomers on the polymerization kinetics, particle size, surface charge density and colloidal properties. The synthesized latexes were monodisperse with a final size between 100 and 600 nm depending on the APMH concentration. The initial polymerization rate and the particle number increased in accordance with the Smith–Ewart theory for soap-free styrene emulsion polymerization with a hydrophilic functional comonomer. The final functionalization rate of the particles has been particularly studied with the intention of fitting the prepared latexes to be used in the immobilization of biological molecules for biological sample preparation and diagnostic applications. © 2020 Society of Chemical Industry.