Crystalline polymer ultrathin films from mesoscopic precursors.

Thin and ultrathin crystalline polymer films are of funda mental scientific as well as practical interest concerning their structures and properties. 6] For the preparation of ultrathin ( 0.1 mm) films the polymer is applied to the substrate in a non ordered state, usually as a dilute solution in an organic solvent. To overcome the intra and intermolecular interac tions responsible for crystalline order in the solid polymer, and render it soluble, high temperatures are often required. Crystalline order only forms on the substrate during solvent removal or cooling. As a different approach to ultrathin films of crystalline polymers we report on their preparation at room temperature from aqueous dispersions of prefabricated polymer nanocrystals functioning as building blocks (Scheme 1). The very small particle size, in combination with the basic phenomenon that the amorphous regions are located at the surface exclusively in polymer single crystals, results in an efficient interaction between particles in films.