Phase separation of polymer thin films and some applications.

摘要

Phase separation of polymer thin film is a common issue in polymer thin film application. The existence of surface and surfactant are understood to play an important role in thin film final topography. In chapter two, the configuration of polymer blend thin film phase separation on cobalt substrate with PMMA phase forming column structure, and PS phase encapsulating the PMMA phase was used as resist mask to transfer the topographical feature to cobalt thin film. Isolated near spherical single and multi domain magnetic islands were obtained. The island made using this method had a broad single domain range from below 1000 to 5000Å. In chapter three, when the polymer blend thin film was in bilayer configuration and diblock copolymer was added on the top layer, we found the confinement can increase the mixing of two homopolymers in highly incompatible polymer blends. By affecting the formation of micelles, the copolymers are forced to the interface between the two homopolymer phases where they reduce the interfacial tension to zero and form a microemulsion. Our findings have two important implications: first, they elucidate the role entropy plays in determining the phase behaviour of confined polymer blends and second, they offer a simple pathway to create thin film coatings with precisely controlled properties and surfaces. In chapter four, the kinetics process of microemulsion formation in confinement configuration has been analyzed. The microemulsion formation proceeded at initial stage by capillary wave, then it followed the growth regime t1/3 and lnt, then followed a more slow growth regime (lnt).56 or (lnt).60 till finally reached equilibrium, when the structure was frozen. In chapter five, we study the evolution of the morphologies of polymer blend thin films on silicon, cobalt, and gold substrates. In asymmetrical system, the substrate surface energy determined the wetting degree of the substrate preferring phases. In chapter six, we present a novel method for producing nanoscale, chemically heterogeneous surface using an Ar ion plasma sputtering source. (Abstract shortened by UMI.)