Effect of monomer sequencing on the phase behavior of novel block copolymer/homopolymer blends
- North Carolina State Univ., Raleigh, NC (United States)
- Univ. of California, San Francisco, CA (United States); and others
Blends consisting of a block copolymer and a parent or block-specific homopolymer exhibit macrophase or microphase separation, depending on (i) the homopolymer chain length relative to that of the host block, (ii) the bulk composition of the blend, and (iii) the state of the copolymer. Recent studies of copolymer/homopolymer blends composed of block, random or alternating copolymers have shown that monomer sequencing plays a crucial role in phase behavior and morphological development. In this work, we examine this effect more closely by probing local segment interactions in both the ordered and disordered block copolymer regimes. In the disordered regime, the effects of blend concentration and molecular weight disparity were analyzed using a poly[(styrene-r-isoprene){prime}-b-(styrene-r-isoprene){double_prime}] (S/I) {prime}-b-(S/I){double_prime} copolymer and three homopolystyrenes of varying molecular weight. To probe segmental interactions in the ordered regime, a series of poly[styrene-b-(styrene-r-isoprene)-b-isoprene] S(S/I)I triblock copolymers has been blended with a single low-molecular-weight homopolystyrene. The phase behavior of all these blends has been examined with transmission electron microscopy (TEM). Electron microtomography was also used to produce the first relatively high-resolution 3-D reconstruction of the L{sub 3} morphology in a copolymer-dilute blend.
- OSTI ID:
- 603004
- Report Number(s):
- CONF-961108-; TRN: 98:001968-0099
- Resource Relation:
- Conference: Annual meeting of the American Institute of Chemical Engineers (AIChE), Chicago, IL (United States), 10-15 Nov 1996; Other Information: PBD: 1996; Related Information: Is Part Of 1996 First joint topical conference on processing, structure and properties of polymeric materials; PB: 594 p.
- Country of Publication:
- United States
- Language:
- English
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