Closed-Loop Transition Induced by Homopolymers
SCIE
SCOPUS
- Title
- Closed-Loop Transition Induced by Homopolymers
- Authors
- Kim, E; Ahn, H; Ryu, DY; Joo, W; Kim, JK; Jung, J; Chang, T
- Date Issued
- 2008-12-23
- Publisher
- AMER CHEMICAL SOC
- Abstract
- The phase behavior for the binary mixtures of a polystyrene-block-poly(n-pentyl methacrylate) (PS-b-PnPMA) and homopolystyrenes (PS) with various molecular weights was investigated by depolarized light scattering and small-angle X-ray scattering (SAXS) as a function of PS amount. A homopolymer-free PS-b-PnPMA, prepared by a high performance liquid chromatography (HPLC) technique, showed the entirely disordered (or homogeneous) state within experimental temperature range from the glass transition temperature (T-g) to the thermal degradation temperature (T-d). By adding PS to this PS-b-PnPMA, the closed-loop phase behavior was observed for the binary mixtures where no macrophase separation occurred. With increasing molecular weight (chain length) of PS, the ordered range of the closed-loop extended remarkably and a critical amount of PS increased, resulting in the conservation of only lamellar morphology Lip to the overall PS volume fraction (f(PS)) of 0.70 for a PS, having a chain length ratio (alpha) of 2 with respect to the PS chain length of PS-b-PnPMA.
- Keywords
- X-RAY-SCATTERING; BUTADIENE BLOCK COPOLYMER; MOLECULAR-WEIGHT HOMOPOLYMERS; PHASE-BEHAVIOR; DIBLOCK COPOLYMER; MICROPHASE SEPARATION; MICELLE FORMATION; ORDERED STRUCTURE; BINARY-MIXTURE; BLENDS
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/28954
- DOI
- 10.1021/MA801530F
- ISSN
- 0024-9297
- Article Type
- Article
- Citation
- MACROMOLECULES, vol. 41, no. 24, page. 9875 - 9881, 2008-12-23
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