Anomaly in SANS χ for polydisperse polystyrene-b-poly(isooctyl acrylate)

Jumi Lee, Hyungju Ahn, Du Yeol Ryu, Kwanwoo Shin, Junhan Cho

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Small-angle neutron scattering (SANS) measurements have been performed on a disordered block copolymer from deuterated polystyrene (dPS) and self-adhesive poly(isooctyl acrylate) (POA) in order to elicit the effective Flory-Huggins χ, which carries the essence of the copolymer phase behavior. The copolymer sample for the measurement was prepared by blending two polydisperse dPS-b-POAs of different molecular weights, where the overall average size of the blend was low enough to ensure to be in the mean-field region but high enough to have discernible scattering intensities. The SANS profiles for the copolymer were fitted to Leibler's scattering function for a polydisperse copolymer system described by Schulz-Zimm distribution. The resultant χ as a function of inverse temperature was shown to have a strong entropic contribution and a weak enthalpic contribution. By adopting Sanchez-Balasz or ten Brinke-Karasz-type simple analysis for specific interactions, it was found that the entropically dominated χ for dPS-b-POA arises from the steric hindrance of long alkyl side groups of POA.

Original languageEnglish
Pages (from-to)2495-2499
Number of pages5
Issue number12
Publication statusPublished - 2012 May 25

Bibliographical note

Funding Information:
This work has been supported by collaborative R&D program with technology advanced country [ 2011-advanced-B-015 ]. J. C. also acknowledges the support from Center for Photofunctional Energy Materials through Gyeonggi Regional Research Center program [ GRRC dankook2011-B04 ].

All Science Journal Classification (ASJC) codes

  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry


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