The present invention relates to surface-modified effect pigments based on flake-form substrates which are distinguished by the fact that they are sheathed with one or more layers of immobilized LCST and/or UCST polymers. The invention furthermore relates to a process for the production of the surface-modified effect pigments and to the use thereof in surface coatings, water-borne coatings, powder coatings, paints, printing inks, security printing inks, plastics, concrete, in cosmetic formulations, in agricultural sheeting and tarpaulins, for the laser marking of papers and plastics, as light protection, as pigment for corrosion protection and for the preparation of pigment compositions and dry preparations.