This study deals with the microstructures of block copolymer and block copolymer/homopolymer blend systems. Self-assembled neat diblock and diblock/homopolymer(s) structures will be formed from chains of various architecture, composition and molecular weight. Emphasis will be placed on novel processing so as to provide large single-crystal-like samples of various desired geometries. The evolution of the microdomain morphology during order-order phase transitions and during mechanical deformation along particular high symmetry directions will be quantitatively followed to obtain information on the fundamentals of phase transitions in block copolymer systems and on their large strain mechanical behavior. The main investigative techniques are roll casting, mechanical testing, optical microscopy, small-angle x-ray scattering, transmission electron microscopy, scanning electron microscopy, digital image analysis, and computer graphics of surfaces. The goal of the research is to contribute to the basic understanding of processing-structure-property relationships, which can provide a basis for development of polymeric materials with improved performance.