Surface-active block copolymers prepared by controlled radical polymerization

A subject-matter of the present invention is a surface-active block copolymer comprising at least one hydrophilic block and at least one hydrophobic block which is prepared by a "living" or "controlled" preparation process, the said copolymer exhibiting a number-average molecular mass of between 1 000 and 50 000, preferably between 2 000 and 20 000, more preferably still between 4 000 and 16 000, a glass transition temperature of the hydrophobic block of less than 30° C., preferably of less than 25° C., and greater than -100° C., and a surface tension of less than 60 millinewtons per metre (mN/m), preferably of less than 50 mN/m, measured at a concentration in demineralized water of less than or equal to 10-4 mol/l, and the transfer agent optionally having been rendered inert with respect to the said radical polymerization. The copolymers obtained can be used in particular in detergency or in paints, adhesives and building materials.