Enthalpic effect of polyacrylonitrile on the concentrated solutions in dimethyl sulfoxide: Strong thixotropic behavior and formation of bound solvents

Youngho Eom, Hyejin Ju, Byoung Chul Kim, Han G. Chae

Research output: Contribution to journalArticle

Abstract

The effect of dipole–dipole interaction by nitrile groups of PAN on the bound state of solvent molecules and the concentrated solution properties in DMSO was investigated. Variation of a solution viscosity exhibited three overlap concentrations, C1*, C2*, and C3*, at 2.7, 8.6, and 16.3 wt%, respectively, representing the transition of concentration regions in the order of dilute, unentangled-semi dilute, entangled-semi dilute, and concentrated regions. The two-dimensional mapping of FT-IR analysis and dielectric measurement confirmed that the intermolecular interaction of PAN was suddenly enhanced at the C*s, inducing polarization to DMSO. In the ice-melting process of PAN solutions, two different melting peaks (Tm2 and Tm3) of DMSO newly appeared at each C2* and C3*, suggesting the different types of bound solvents. In the concentrated solutions, the saturated dielectric constant and the strongly delayed evaporation of the solvent even at the boiling point of DMSO along with strong thixotropic behavior were indicative of the stronger confinement state of bound DMSO than in the semidilute solutions.

Original languageEnglish
Pages (from-to)1080-1089
Number of pages10
JournalJournal of Polymer Science, Part B: Polymer Physics
Volume57
Issue number16
DOIs
StatePublished - 2019 Jan 1

Keywords

  • bound solvent
  • enthalpic effect
  • polarization
  • polyacrylonitrile solution
  • thixotropy

Fingerprint Dive into the research topics of 'Enthalpic effect of polyacrylonitrile on the concentrated solutions in dimethyl sulfoxide: Strong thixotropic behavior and formation of bound solvents'. Together they form a unique fingerprint.

  • Cite this