Method for the gradual release of polymer chains within a liquid release medium, said method comprising a step where said medium is brought into contact with solid objects, typically granular objects, formed by polymer chains soluble in the medium and carrying hydrophobic side groups ensuring hydrophobic/hydrophobic physical crosslinking between said polymer chains within said solid objects, wherein the medium is an aqueous medium where the released polymer chains are water-soluble, wherein the solid objects employed in step result from a step of micellar radical polymerization in which the following are brought into contact, within an aqueous medium: - ethylenically unsaturated monomers, dissolved or dispersed in said aqueous medium; - ethylenically unsaturated hydrophobic monomers, in the form of a micellar solution, namely containing, in the dispersed state within the medium, micelles comprising these hydrophobic monomers, said monomers being, in all or part, monomers carrying hydrophobic chains suitable for ensuring the desired hydrophobic/hydrophobic physical crosslinking in the solid objects employed in step; - at least one radical polymerization initiator, which is preferably water-soluble or water-dispersible; and - at least one radical polymerization control agent, the radical polymerization control agent being a compound comprising at least one thiocarbonylthio -S(C=S) group, for example a xanthate; wherein the monomers employed in step contain monomers (mR) comprising at least two ethylenic unsaturations separated by at least one cleavable group, the cleavable group being selected from divalent -ester-; -amide-; -ether-; -ether phosphate-; -ether sulfate-; - carbonate- and -carbamate- groups; and wherein the molar ratio (mR)/, which corresponds to the amount of crosslinking monomers (mR) with respect to the total amount of hydrophilic monomers, is greater than 2%. wherein the medium is an aqueous medium where the released polymer chains are water-soluble, wherein the solid objects employed in step result from a step of micellar radical polymerization in which the following are brought into contact, within an aqueous medium: - ethylenically unsaturated monomers, dissolved or dispersed in said aqueous medium; - ethylenically unsaturated hydrophobic monomers, in the form of a micellar solution, namely containing, in the dispersed state within the medium, micelles comprising these hydrophobic monomers, said monomers being, in all or part, monomers carrying hydrophobic chains suitable for ensuring the desired hydrophobic/hydrophobic physical crosslinking in the solid objects employed in step; - at least one radical polymerization initiator, which is preferably water-soluble or water-dispersible; and - at least one radical polymerization control agent, the radical polymerization control agent being a compound comprising at least one thiocarbonylthio -S(C=S) group, for example a xanthate; - ethylenically unsaturated monomers, dissolved or dispersed in said aqueous medium; - ethylenically unsaturated hydrophobic monomers, in the form of a micellar solution, namely containing, in the dispersed state within the medium, micelles comprising these hydrophobic monomers, said monomers being, in all or part, monomers carrying hydrophobic chains suitable for ensuring the desired hydrophobic/hydrophobic physical crosslinking in the solid objects employed in step; - at least one radical polymerization initiator, which is preferably water-soluble or water-dispersible; and - at least one radical polymerization control agent, the radical polymerization control agent being a compound comprising at least one thiocarbonylthio -S(C=S) group, for example a xanthate; wherein the monomers employed in step contain monomers (mR) comprising at least two ethylenic unsaturations separated by at least one cleavable group, the cleavable group being selected from divalent -ester-; -amide-; -ether-; -ether phosphate-; -ether sulfate-; - carbonate- and -carbamate- groups; and wherein the molar ratio (mR)/, which corresponds to the amount of crosslinking monomers (mR) with respect to the total amount of hydrophilic monomers, is greater than 2%.