Closed-loop transition induced by homopolymers

Kim Eunhye, Ahn Hyungju, Yeol Ryu Du, Joo Wonchul, Kon Kim Jin, Jung Jueun, Chang Taihyun

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


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 (Tg) to the thermal degradation temperature (Td). 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 up to the overall PS volume fraction (fps) of 0.70 for a PS, having a chain length ratio (α) of 2 with respect to the PS chain length of PS-b-PnPMA.

Original languageEnglish
Pages (from-to)9875-9881
Number of pages7
Issue number24
Publication statusPublished - 2008 Dec 23

All Science Journal Classification (ASJC) codes

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry


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