The present invention concerns an aqueous dispersion of multiphase polymer particles in which the polymer particles comprise at least two separate phases, the internal phase being formed by polymerization in the presence of a crosslinking agent, said dispersion further comprising a surfactant chosen from amino acid derivatives. The invention also concerns a film-forming composition comprising said aqueous dispersion of polymer particles. The invention also relates to a film obtained after application of said film-forming composition. This film dries very quickly, is water resistant, and has good adhesion, elasticity and breaking strength properties. The invention also concerns the use of said film for protecting surfaces of the skin or mucous membranes, wounds, injuries and/or skin disorders.