| 초록 |
Ordering of cylindrical microdomains in a low molecular weight polystyrene-block-polyisoprene (SI diblock) copolymer was investigated using small-angle-X-ray scattering (SAXS) and rheology. The SI diblock copolymer was found to have (i) hexagonally-packed cylindrical microdomains of polystyrene phase in a polyisoprene matrix in the ordered state, and (ii) an order-disorder transition temperature (TODT) of ca. 90oC. To investigate the ordering process from the disordered state, a specimen was quenched rapidly from the disordered state to a temperature below its TODT, and then the time evolution of the SAXS intensity and dynamic moduli (G’ and G") (i.e. the ordering process) was monitored. We have found that the ordering process in the block copolymer, when quenched to an ordered state close to its TODT, takes very slowly. Specifically, we found that when a specimen was quenched rapidly from 100 (10oC above TODT) to 80oC (10oC below TODT), the ordering into the hexagonally-packed cylinders occurs via a nucleation-growth process and the attainment of the equilibrium microdomain morphology took about 6 h when monitoring G’ and G" and about 8 h when monitoring SAXS intensity.
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