Effective interaction parameter for homologous series of deuterated polystyrene-block-poly(n-alkyl methacrylate) copolymers

Du Yeol Ryu, Changhak Shin, Junhan Cho, Dong Hyun Lee, Jin Kon Kim, Kristopher A. Lavery, Thomas P. Russell

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The effective interaction parameters, (χ F ) of the homologous series of deuterated polystyrene-block-poly(n-alkyl methacrylate) copolymers (dPS-b-PA n MA) from methyl (n = 1) to hexyl (n = 6) side groups have been investigated by small-angle neutron scattering and a Hartree (fluctuation correction) analysis. While χ F for dPS-b-PA n MA with n = 1 and 6 is a typical decreasing function of temperature, it is shown that χ F for n from 2 to 4 changes to a monotonic increase with temperature, revealing growing upward convexity. This action culminates in a maximum of χ F for n = 5, which suggests an immiscibility loop-type behavior. Using the Hartree analysis for compressible diblock copolymers, the effect of directional interactions and the compressibility difference between the constituent blocks on χ F is discussed. The ordering transition temperatures, their pressure dependences, and χ F for the homologous block copolymer series are shown to be in good agreement with the experimental values.

Original languageEnglish
Pages (from-to)7644-7655
Number of pages12
Issue number21
Publication statusPublished - 2007 Oct 16


All Science Journal Classification (ASJC) codes

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

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