An inverse latex comprising an oil phase, an aqueous phase, at least one water-in-oil emulsifying system, and a linear, branched or crosslinked cationic polyelectrolyte resulting from the polymerization, for 100 mol %:
- a) of a molar proportion greater than 40% and less than or equal to 99% of monomeric units resulting from at least one cationic monomer,
- b) of a molar proportion greater than or equal to 1% and less than 60% of monomeric units resulting from N-(2-hydroxyethyl) acrylamide, and
- c) optionally of a molar proportion greater than 0% and less than 30% of monomeric units resulting from at least one neutral monomer different than said N-(2-hydroxyethyl)acrylamide, it being understood that this molar proportion is strictly less than that of the monomeric units resulting from N-(2-hydroxyethyl) acrylamide, and
- d) optionally of a molar proportion greater than 0% and less than or equal to 1% of a diethylenic or polyethylenic crosslinking monomer.