Phase Behavior of a Weakly Interacting Polystyrene and Poly(n-hexyl methacrylate) System: Evidence for the Coexistence of UCST and LCST
✍ Scribed by Hyungju Ahn; Sudhakar Naidu; Du Yeol Ryu; Junhan Cho
- Publisher
- John Wiley and Sons
- Year
- 2009
- Tongue
- English
- Weight
- 383 KB
- Volume
- 30
- Category
- Article
- ISSN
- 1022-1336
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✦ Synopsis
Abstract
The phase behavior of a weakly interacting binary system composed of deuterated polystyrene (dPS) and poly(n‐hexyl methacrylate) (P__n__HMA) was investigated by the turbidity measurement for the binary blend, and by small angle X‐ray scattering (SAXS) and depolarized light scattering for the block copolymers. For the binary dPS/P__n__HMA blend, a new phase diagram involving both the upper critical solution transition (UCST) and lower critical solution transition (LCST) was observed by the delicate control of molecular weights between dPS and P__n__HMA. Whereas for the block copolymers such as dPS‐block‐P__n__HMA and PS‐block‐P__n__HMA, an order‐to‐disorder transition (ODT) on heating was observed within the experimental temperature range depending on the molecular weight. This coexistence of both a UCST and LCST in the dPS/P__n__HMA blend consequently represents the experimental evidence that the corresponding (d)PS‐b‐P__n__HMAs possess not only ODT, but also lower disorder‐to‐order transition (LDOT) character driven by a compressibility difference, although the latter is hindered by thermal degradation.
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