Chloroprene emulsion polymerization experiments have been carried out, using either the colophane or a reactive maleic hemiester as surfactant. In the later case, one may observe a rather rapid nucleation and chiefly an early gel formation even at a temperature as low as 12 ºC. The reasons for that are not quite clear, although the efficiency of the mercaptane  used as transfer agent is reduced, possibly because in that case the optimal pH conditions  are different form those used in the case of colophane  ( 9 instead  of 12 ) . The crystallinity is strongly reduced by the early formation of gel. However an advantage of using  the reactive surfactant  is to reduce the water uptake of the films formed by coalescence of the latex particles.