Described is a method for the preparation of polymer nanoparticles based on polyethylacrylic acid homopolymer (PEA) by heating partially neutralized aqueous solution of PEA below lower critical solution temperature. Nanoparticles are formed following aggregation of polymer chain as a result of solvent quality deterioration with increasing temperature. Subsequently polymer nanoparticles are stabilized by hydrogen bonds.Described is a method for the preparation of polymer nanoparticles based on polyethylacrylic acid homopolymer (PEA) by heating partially neutralized aqueous solution of PEA below lower critical solution temperature. Nanoparticles are formed following aggregation of polymer chain as a result of solvent quality deterioration with increasing temperature. Subsequently polymer nanoparticles are stabilized by hydrogen bonds.