Miktoarm star block copolymers : effects of molecular architecture on morphology /

MIKTOARM STAR BLOCK COPOLYMERS: EFFECTS OF MOLECULAR ARCHITECTURE ON MORPHOLOGY FEBRUARY 2002 LIZHANG YANG, B.S., BEIJING UNIVERSITY M.S., UNIVERSITY OF MASSACHUSETTS AMHERST PH.D., UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Samuel P. Gido Three aspects of the effects of molecular architecture on block copolymer and block copolymer / homopolymer blends morphological behavior have been investigated. In the Chapter 2 and 3, the morphological behaviors of "Model" graft block copolymer / homopolymer blends was discussed. The morphological behaviors for two distinct types of graft architectures were investigated. The first type, LS block copolymers, which have 2 low polydispersity (PD1) polyisoprene arms and one low PDI polystyrene arm joint at a single junction point, has an asymmetry, non-linear molecular architecture. The second type, I2S 2 block copolymers, which have 2 low PDI polyisoprene arms and two low PDI polystyrene arms joint at a single junction point, has a symmetry, non-linear molecular architecture. In the blend study, a slow co-casting procedure was developed to get single crystal structure of Gyroid morphology. The amazing scattering patterns of this sample provide the best evidence for Gyroid morphology observed so far.