Polymerizable surfactants derived from maleic anhydride have been synthesized. The hydrophilic part is obtained by a controlled ethylene oxide polymerization according to a new heterogeneous catalytic process. Some maleates derivatives have been obtained and fully characterized by H-1 and C-13 NMR. Their cmc were also measured. Some of them have been engaged in styrene emulsion polymerization in which monodisperse latex particles have been produced.