A waterborne dispersion comprising amphiphilic block copolymer obtained with a controlled radical polymerization process and comprising at least blocks and, whereby block comprises ethylenically unsaturated monomer(s) bearing water-soluble and/or water-dispersible functional groups (monomer(s) (i)), and block comprises ethylenically unsaturated monomer(s) different from monomer(s) (i) (monomer(s) (ii)); and polymer P comprising ethylenically unsaturated monomer(s) different from (i) (monomer(s) (ii)), characterized in that the amount of block copolymer is higher than 1 and lower than 30 wt.%, based on the total weight of monomers used to prepare the block copolymer and polymer P; the acid value of the composition consisting of block copolymer and polymer P is higher than 1 and at most 35 mg KOH per g of the block copolymer-polymer P composition; the block copolymer has a calculated glass transition temperature of higher than 10 °C and lower than 250 °C; and polymer P comprises at least 20 wt.% (relative to the total monomer composition to prepare the polymer P) of a polymer fraction with a calculated glass transition temperature higher than 10°C and lower than 100°C. amphiphilic block copolymer obtained with a controlled radical polymerization process and comprising at least blocks and, whereby block comprises ethylenically unsaturated monomer(s) bearing water-soluble and/or water-dispersible functional groups (monomer(s) (i)), and block comprises ethylenically unsaturated monomer(s) different from monomer(s) (i) (monomer(s) (ii)); and block comprises ethylenically unsaturated monomer(s) bearing water-soluble and/or water-dispersible functional groups (monomer(s) (i)), and block comprises ethylenically unsaturated monomer(s) different from monomer(s) (i) (monomer(s) (ii)); and polymer P comprising ethylenically unsaturated monomer(s) different from (i) (monomer(s) (ii)), characterized in that the amount of block copolymer is higher than 1 and lower than 30 wt.%, based on the total weight of monomers used to prepare the block copolymer and polymer P; the acid value of the composition consisting of block copolymer and polymer P is higher than 1 and at most 35 mg KOH per g of the block copolymer-polymer P composition; the block copolymer has a calculated glass transition temperature of higher than 10 °C and lower than 250 °C; and polymer P comprises at least 20 wt.% (relative to the total monomer composition to prepare the polymer P) of a polymer fraction with a calculated glass transition temperature higher than 10°C and lower than 100°C. the amount of block copolymer is higher than 1 and lower than 30 wt.%, based on the total weight of monomers used to prepare the block copolymer and polymer P; the acid value of the composition consisting of block copolymer and polymer P is higher than 1 and at most 35 mg KOH per g of the block copolymer-polymer P composition; the block copolymer has a calculated glass transition temperature of higher than 10 °C and lower than 250 °C; and polymer P comprises at least 20 wt.% (relative to the total monomer composition to prepare the polymer P) of a polymer fraction with a calculated glass transition temperature higher than 10°C and lower than 100°C.