Influence of carbon dioxide swelling on the closed-loop phase behavior of block copolymers

Kristopher A. Lavery, James D. Sievert, James J. Watkins, Thomas P. Russell, Du Yeol Ryu, Jin Kon Kim

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


The influence of carbon dioxide sorption on the closed-loop phase diagram of polystyrene-block-poly(n-pentyl methacrylate) copolymers, PS-b-PnPMA, was investigated. Differential dilation of the constituent blocks was used to induce microphase separation of the PS-b-PnPMA. With increasing carbon dioxide loading an appreciable expansion in the size of the closed loop was found. At a carbon dioxide activity of 0.1 the upper order-to-disorder transition temperature (UODT) was elevated by more than 20°C, whereas the lower disorder-to-order transition temperature (LDOT) was depressed by the same magnitude. This arises from the entropic nature of the closed-loop miscibility gap in this weakly interacting system, where microphase separation is driven by disparity in free volumes between dissimilar segments of the chain.

Original languageEnglish
Pages (from-to)6580-6583
Number of pages4
Issue number19
Publication statusPublished - 2006 Sept 19

All Science Journal Classification (ASJC) codes

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


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