Depolarized Scattering from Block Copolymer Grains Using Circularly Polarized Light

Xin Wang, Xiuhong Li, Whitney Loo, Maurice C. Newstein, Nitash P. Balsara, Bruce A. Garetz

Research output: Contribution to journalArticle

Abstract

The grain structure of ordered block copolymer materials affects their viscoelastic, adhesive, optical, and electrical properties. Depolarized light scattering has proven to be an important method for characterizing this grain structure. In this paper, we use both theory and experiments to demonstrate the relationship between grain structure and depolarized light scattering from ordered block copolymer samples performed with crossed circular polarizers. We model the sample assuming it comprises randomly oriented ellipsoidal grains with optic axes coincident with the ellipsoid axes. We show that the scattering pattern obtained using circularly polarized (CP) light is azimuthally symmetric, in contrast to that obtained using linearly polarized (LP) light which exhibits 4-fold angular modulation. The integrated scattered power in the CP case is twice as large as that in the LP case. By simultaneously fitting CP and LP light scattering data, we obtain robust measures of parameters that characterize grain structures. In addition, CP light scattering can, in principle, be used to characterize nonrandom grain orientation distributions.

Original languageEnglish (US)
Pages (from-to)5122-5131
Number of pages10
JournalMacromolecules
Volume50
Issue number13
DOIs
StatePublished - Jul 11 2017

ASJC Scopus subject areas

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

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