Preferential Wetting Effects on Order-to-Disorder Transition in Polystyrene-b-poly(2-vinylpyridine) Films: A Reconsideration on Thickness Dependence

Yeongsik Kim, Daeseong Yong, Wooseop Lee, Seongjun Jo, Hyungju Ahn, Jaeup U. Kim, Du Yeol Ryu

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

We present a compelling evidence for thickness dependence on the order-to-disorder transition (ODT) behavior in cylinder- and lamella-forming polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) films. Such an asymmetric wetting condition that confines the films with selective interactions of the PS/air and P2VP/substrate interfaces generates a parallel orientation of cylindrical and lamellar microdomains. We evaluated thickness-dependent phase transition as a function of interlattice distance (L0) using ex situ grazing incidence small-angle X-ray scattering (GISAXS) and transmission electron microscopy (TEM). Below an onset thickness (t0) above which the ODT temperatures (TODTs) of the films are independent of film thickness, the TODTs of cylinder- and lamella-forming PS-b-P2VP films remarkably increase as the film thickness decreases. Our results confirmed that preferential wetting at the PS/air and P2VP/substrate interfaces in very thin films substantially leads to an ordered state over accessible temperature range up to ∼260 °C. More interestingly, the t0 of lamellar morphology (∼22L0) is thicker than that of cylindrical morphology (∼10L0), indicating that the interfacial interactions are more influential to a 1D multilayer structure of lamellar microdomains than a 2D hexagonally packed order of parallel cylinders. Our theoretical calculation utilizing the self-consistent field theory (SCFT) of a discrete bead-spring model with finite-range interactions exhibited the similar thickness dependence of ODTs for cylinder- and lamella-forming PS-b-P2VP films confined in such an asymmetric wetting condition.

Original languageEnglish
Pages (from-to)8550-8560
Number of pages11
JournalMacromolecules
Volume51
Issue number21
DOIs
Publication statusPublished - 2018 Nov 13

All Science Journal Classification (ASJC) codes

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

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