Synthesis and Characterization of Ion- containing Polymers

Open Access
Author:
Dou, Shichen
Graduate Program:
Materials Science and Engineering
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
December 07, 2006
Committee Members:
  • Ralph H Colby, Committee Chair
  • Janna Kay Maranas, Committee Member
  • Qing Wang, Committee Member
  • Ronald Hedden, Committee Member
Keywords:
  • Polyelectrolyte
  • SAXS
  • rheology
  • ionomers
  • synthesis
Abstract:
Two types of ion-containing polymers are included in this dissertation. The first was focused on the rheology, solvation, and correlation length of polyelectrolyte solutions in terms of charge density, solvent dielectric constant, and solvent quality. The second was focused on the PEO-based polyester ionomers as single ion conductors. A series of polyelectrolytes with varied charge density (0.03 to 0.6) and counterions (Cl- and I-) were investigated in good solvent (EG, NMF, and GC) and poor solvent (DW and F). The concentration dependence of the specific viscosity and relaxation time of polyelectrolytes in solution agrees with Dobrynin’s theoretical predictions at. Effective charge density greatly impacts the viscosity of polyelectolyte semidilute solutions, while residual salt significantly reduces the viscosity of polyelectrolyte solutions at concentrations . For polyelectrolyte solutions with less condensed counterions, the correlation length obtained from SAXS and rheology perfectly matches and agrees with de Gennes prediction. Dobrynin scaling model successfully predicts the rheology of polyelectrolyte solutions in all cases: without salt, with low residual salt, and with high residual salt concentration. PEO-based polyester ionomers were synthesized by melt polycondensation. Mn was determined using the 1H NMR of ionomers. No ion-cluster was observed from the DSC, SAXS, and rheology measurements. Ionic conductivity greatly depends on the Tg, T-Tg and ion content of the ionomers. PEG600-PTMO650 (z)-Li copolyester ionomers show microphase separation and much lower ionic conductivity, compared to that of PE600-Li. PTMO650-Li shows nonconductor behavior.