PMSE 171 |
| Manipulation of helical nanostructures from chiral diblock copolymers, poly(styrene)-b-poly(L-lactide) (PS-PLLA), by crystallization under confinement has been studied. Various crystalline PS-PLLA nanostructures were obtained by simply controlling the crystallization temperature of PLLA (Tc, PLLA) at which crystalline nanohelices (PLLA crystallization within helical confined microdomain) and stretched nanohelices (stretching of helical nanostructure by crystallization) occurred while Tc, PLLA < Tg, PS (the glass transition temperature of PS) and Tc, PLLA >= Tg, PS, respectively. The PLLA crystallites within the crystalline nanohelical and stretched nanohelical (i.e., crystalline cylindrical) microdomains revealed unique anisotropic character. Detailed investigation of the crystalline orientation associated to crystalline naonohelices and crystallization-induced cylinder was carried out so as to identify the shape effect of self-assembly microdomains on crystallization and the mechanism of crystallization-induced stretching of the helical nanostructure. |
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50 Years after the Discovery of Polymer Single Crystals: A Look Back, Current Discoveries and Future Opportunities
8:30 AM-12:15 PM, Tuesday, August 21, 2007 Westin Boston Waterfront -- Alcott, Oral
Division of Polymeric Materials: Science & Engineering |