Structure of poly(ionic liquid)s in solutions: a small angle scattering study

ChemRxiv

Abstract

We investigate the phase behaviour and scattering properties of a polymerised ionic liquid (poly(1-butyl- 3-vinylimidazolium bis(trifluoromethanesulfonyl)imide)) in 24 solvents of varying dielectric constants and solubility parameters. The polymer is found to be soluble in polar aprotic solvents and insoluble in non- polar or highly protic solvents. Three types of behaviour can be observed: in high permittivity solvents, the correlation length is inversely proportional to the square root of the polymer concentration c, and the proportionality constant decreases with solvent dielectric constant if the Bjerrum length is larger than ≃ 1 nm. For solvents with modest dielectric constants (ε ≃ 18 − 30), the correlation length scales as ξ ∝ c−1/3, suggesting a pearl-necklace conformation. Finally, in THF, the scattering pattern follows the Ornstein- Zernike behaviour. The scaling of the correlation length and zero-angle scattering intensity are similar to those of neutral polymers in good solvents. The solvophobic polyelectrolytes.

Authors 8

1. Carlos G. Lopez

   Pennsylvania State University

   Affiliation as printed

   Pennsylvania State University

2. Atsushi Matsumoto

   University of Fukui

   Affiliation as printed

   University of Fukui

3. Anish Gulati Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University

4. Yuna Mizutani

   Okayama University

   Affiliation as printed

   Okayama University

5. Yume Tao

   Okayama University

   Affiliation as printed

   Okayama University

6. Kakeru Fujii

   Okayama University

   Affiliation as printed

   Okayama University

7. Walter H. Richtering Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University

8. Takaichi Watanabe

   Okayama University

   Affiliation as printed

   Okayama University